Brian:
??? I will agree that the 860 is on the minimal side, but I'm not
a family man, and sail single handed normally.? The voyager is
absurdly huge for my needs.? My direction is less rather than
more, which perhaps is a mistake..... but it is my normal mode of
existence.?? I live "small" because I live "out of a house", not
"in a house"...... does that make any sense???? My entire thrust
is toward smaller and simpler, and lighter.? It all points to less
cost at every level, and my budget is limited, and what I have I
want to spend cruising, not on up front costs or continued
maintenance costs.???
??? The 860 appeals to me in many ways.? I feel Bernd made all the
right choices, though the scale is just a tad small.?? The 980
variant, which he does not offer as a plans set, or Pete's 10
meter variant, just about nail it for me.?? I don't want a 40'
boat.???
??? In "real life", we must compromise....... we can't have
everything we want....... I don't live in the "big rock candy
mountain" fantasy land with the lemonade springs and the cigarette
trees, and the little streams of alcohol trickling down the rock,
where the sun shines every day and the bluebird sings....
etc.........????
??? The reality is that what works for me, probably will not work
for you, and vice versa, we have different priorities.? What I do
NOT want is to be pushed into a bigger and bigger boat.?? It's
been said again and again..... and it is right.........?? The
biggest mistake people make is to buy too big a boat, the second
biggest mistake is to buy to small a boat......for their
needs.???? In the multihull world, I'm seeking the "right"
boat....... it isn't a 40 footer.
??? Talk is cheap, so they say..... In all likelyhood, I'll never
own one of Bernd's designs, as much as I admire his work.?? I
don't plan to build a boat on that scale........ I'm currently
building my fourth small boat, and plan to build number 5 not long
after..... a simple stitch and glue dinghy.?? I'd lay down the
cash and sail Oryx away in a heartbeat, if it wouldn't wipe out
most of my cruising budget... Pete has it for sale.?? I'm a "penny
ante" player, not a high roller.?? Everything about the 860
appeals to me, except that the size is just a tad small.
??? Pete Hill of course brought Bernd's designs to my attention
with Oryx.? I've followed Pete, Annie, and Carly since the days of
Badger..... before that I had dismissed small cats as completely
impractical, though a few designers like Richard Woods, and Roger
Simpson, were at least interesting.?? I never fell under the spell
of Warram, but living in a temperate climate that should be
understandable.
??? It's obviously a tough business.... when you go really large,
things start to work well on a cat.? I don't need or want a "condo
cat".???? There really is no "free lunch" here.
????????????????????????????????????????????????????? H.W.
On 11/24/2017 10:11 AM, bryanandmarycox@... [k-designs]
wrote:
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?
Hi?
as a small multihull sailor (Duo480 Jigsaw) I am all
too well of the drop in performance of a multihull when it
is loaded up with extras. However I just day sail mostly,
and yet carrying a motor, anchors, chain, cooler bins,
makes a huge difference to the performance.?
I believe this was Andrew's main point. The KD860
itself is more than capable of sailing off shore, but when
you add in the weight of the extra equipment and supplies
needed for extended off shore cruising then the weight
limits are reached very quickly. This is the heart of the
matter and the design is irrelevant . For a multihull, a
boat of less than 9 metres is just too small to carry the
load efficiently, and it doesnt matter who the designer
is. That is my very firm belief.
I am a great fan of the KD860, and if I were to build a
bigger boat this would be the one. But I would not plan on
sailing it from here in New Zealand to Hawaii or anything
like that, for the above reasons. As for the other factors
mentioned, eg sails: I dont understand junk rigs so I
would never choose them. Our local harbour has a very
strong tidal movement so I would consider a dagger board
instead of the AV panels.
Actually, as I have found with the Duo 480, and also
the KD650 on which I have sailed often, the asymmetric
hulls work really well, and so I would suggest to you why
not go for the Voyager, and then your concerns about off
shore capability would be not a factor.
regards
?Bryan
|
Hi? as a small multihull sailor (Duo480 Jigsaw) I am all too well of the drop in performance of a multihull when it is loaded up with extras. However I just day sail mostly, and yet carrying a motor, anchors, chain, cooler bins, makes a huge difference to the performance.?
I believe this was Andrew's main point. The KD860 itself is more than capable of sailing off shore, but when you add in the weight of the extra equipment and supplies needed for extended off shore cruising then the weight limits are reached very quickly. This is the heart of the matter and the design is irrelevant . For a multihull, a boat of less than 9 metres is just too small to carry the load efficiently, and it doesnt matter who the designer is. That is my very firm belief.
I am a great fan of the KD860, and if I were to build a bigger boat this would be the one. But I would not plan on sailing it from here in New Zealand to Hawaii or anything like that, for the above reasons. As for the other factors mentioned, eg sails: I dont understand junk rigs so I would never choose them. Our local harbour has a very strong tidal movement so I would consider a dagger board instead of the AV panels.
Actually, as I have found with the Duo 480, and also the KD650 on which I have sailed often, the asymmetric hulls work really well, and so I would suggest to you why not go for the Voyager, and then your concerns about off shore capability would be not a factor.
regards ?Bryan
|
Bernd:
??? I'm not at all what this is intended to mean..........
On 11/24/2017 05:44 AM, Bernd@... [k-designs] wrote:
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?
right, anyway with a load factor of 1 : 2 it is more as
okay as customers who made and make ocean passages
reported to me
|
Andrew:
??? This is exactly the problem I'm wrestling with.?? Multihulls
have limited load carrying capacity, and as Bernd mentioned I've
been looking at some of Jim Brown's Searunners, and to get the
same payload means going with the 37 footer........ that's a BIG
boat.?? The problem of course is what constitutes "payload" and
"dry weight" is something I believe varies significantly from
designer to designer, and as Bernd pointed out, it's easy to over
build, and people have a tendency to doll boats up with pretty
stuff that is not particularly valuable, but adds to weight.?? I
am beginning to realize that virtually all small multihulls are
overloaded when making passages.?
??? The only way I can see to judge real world weight and payload
for an individual boat meaningfully, would be to have the boat
sitting in the water as equipped..... rig, anchors and rode, and
other known items, then load it using plastic drums of water or
sand bags, etc until it was sitting at LWL.?? This would give a
real world working payload...... each drum of water would work out
to about 215 kg, and they could be properly distributed and filled
using a pump and siphoned out.??? I consider something like this a
reasonable first step before even doing a survey.? Can it
realistically do what I want to do is the first question.??
??? I'm mostly a single hander....... it's my nature, I enjoy
solitude, however it's only logical on a long passage, say the
Canaries to Barbados, or Panama to the Pacific Islands to take on
a crew member.? That alone adds up to about 250 lbs of human flesh
and gear, plus 4.2 pounds of water per day, and probably 3 pounds
of food....... Let's say 500 total additional pounds for a
crossing including a safety margin.??? As Bernd points out a
watermaker makes sense when looking at 250 pounds of water plus
containers..... a human powered water maker would be great.... You
want a fresh water shower... start pedaling!?? A water maker also
makes it possible to reduce the weight of food stores.?? Things
like beans, rice, noodles, dried foods, etc, all require water to
prepare, and are all light weight high energy foods.?? You can
only reduce spares by having fewer systems / simpler systems.? The
junk rig with it's free standing mast(s) eliminates all standing
rigging.? It doesn't require winches, or a mast with a track and
slides, it doesn't require a traveler or a vang, and it only has a
single sail per mast.? Tacking is almost a simple as making a lane
change in your car.? You can reef with a cup of coffee in one hand
without spilling it.? Blondie Hassler crossed the Atlantic in
Jester wearing bedroom slippers...... or so he claimed.??? In my
book, simple is best, even if it means sacrificing a bit of
convenience, and speed.??? Simpler ultimately ends up being
lighter in most cases.?? How much stuff can I NOT have??? Pumped
water and flush toilets are at the top of the list to eliminate.??
A plastic jug with a spigot on a shelf is "running water".?? A
black plastic bag hanging in the sun.... solar shower / water
heater.??? Propane bottles weigh nearly as much as the fuel in
them, and are an absurd cooking fuel for a light weight boat.??
I've seen photos of big heavy wooden tables in the saloon on these
boats........? absurd dead weight that takes displaces payload.??
Looking at the interior photos of cats, one sees all kinds places
where weight could be removed or reduced.??
????????????????????????????????????????????????????????????????????????????????????
H.W.
On 11/23/2017 05:16 PM, andrewklees@... [k-designs]
wrote:
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?
Hi. the boat was designed to be offshore capable and Is
I'm my opinion. However a catamaran of this size is on the
cusp of what you can get away with for extended cruising
and live aboard use. I Think Richard woods intimates this
for his cruising designs in the 8 -9m size as well.
The problem with catamarans is, you have all the space
in the world to put stuff, but not the ability to cary it
(safely). As opposed to a monohull, where it will take the
weight but no space to put it. Having 2 hulls (that are
slender enough to perform as a sailing boat) does not add
up to great payload capacity
Plenty of people put all there cruising gear in small
catamarans, but look were the water line ends up. On
pictures of Oryx the water line is well above the
transoms. The designed fully loaded waterline is supposed
to be with the transoms just clear of the water for the
KD860. You can pile as much stuff as you like into a small
catamaran and it won't sink, but will it still be sea
worthy?
When you add up the weight of all the gear that you
would take for long
term cruising, it becomes significant.
for example.-
Main anchor and rode, spare anchor and rode, fenders
and fender boards, shore lines, engine spares, boat repair
spares, safety gear, sufficient battery capacity and
charging ability to run an autopilot 24h/day, dingy and
oars, fuel , water, food, people, peoples clothes and
personal items, nav charts and books guides etc, rigging
spares, spare autopilot or parts, droge and or sea anchor
+ warps, stuff to cook on and eat off, first aid gear. And
it just goes on and on.
So the simple thing to do, is do a calculation on your
expected payload that you require, and get a boat designed
to carry it, the Kd860 may or may not be the boat for your
application.
In my situation, I wanted the smallest boat that I
could , single hand, do extended coastal cruising, do occasional?offshore
passages, afford to build and maintain. And in that
respect the KD860 is perfect. For living aboard as a
couple and long term cruising on a budget, I think the
voyager design would be the choice.?
Cheers…... Andrew.
|
|
|
right, anyway with a load factor of 1 : 2 it is more as okay as customers who made and make ocean passages reported to me
|
Hi Andrew
?Thanks for your throughts about the KD 860 after your very negative end statement of your last letter. Multihulls are load sensitive of course, because ascelleration in a squall is there only devence. The KD 860 is here no exeption. But the boat is extreme stable by design. See the dynamic stability calculation which is extrem conservative. Because I calculate with a safety factor of + 90%!!!!! I add the dynamic stability diagram. When you look at this interesting facts are obviouse. The maximum rigthing moment is 5400kg with the sail area of 37m2. At an angle of 55 degree(windforce 30 knots full sail) ?there is a recovery hump with an righting moment of still 1300kg, which gives you time to release the mainsheet and bear away. As a small reminder, never luff a multihull in such an situation, the rotational added moment ( weigth of the rigg) would turm the boat over. Nobody in his right mind would sail in a wind of 30 knots with full sail, also a small sail as this of the KD 870. It is per design no racing boat. This is reflected as you observed with the low apect ratio of the hulls which is in this case 1 : 8. Normally I design not under 1 : 12. Here we have also the reason the boat has a good load factor. Which makes the boat cabable for longer yournay.? About 17 % of my clients are members of these group. Logical it is an English language group. I have clients in Swasiland the can read drawings but not the language. My Japanese friends have the same problem. 7? KD 860 are used as life on board boats because of the relative high load factor.. Some solo, others as couble, All of them made long passages without any problem. Two are now sailing around the world. I get sometimes a letter, because the are not interested in the Internet, the are happy to be away from just this part of or sillivication (no mistake). Speed, as mentioned it is no racer, the report etmals of 180 to 200 miles. This is a medium speed of 7 knots. Our Pelican was very fast and 16 knots was not unusual. But lucky we have a brake on multis, shorten sail. Above 11 knots any cutlery starts to rattle. When I, or my wife where cooking, we slowed the boat alwise down. In conversations with other sailes, the where done the same. A time ago I was reading an article in french "Multoque". The where sailing a "Tectron" from Canada to France. When cooking the did the same. Racing is a differnt story, I know in the days of the first multihull races. The had a lot of cakes on board for food. Nothing to cook and sufficient calories for the hard work. I will go into the load capacity and what to have on boart (anchor etc) in my answer to H.M. Thanks for your througths, which is at least more, as your statement in your last letter that the KD 860 is not suitable.
Bernd ?
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> Distance waterline bridge deck as shown 600 and 700mm from the cockpit.
It isn't right. At KD860 project it's 500 and 600mm
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Re: electric motor experiments
?An RC propeller actually works very well in water.? For decades the APC brand of RC propellers were the choice of human powered watercraft not only for high efficiency in low rpm water drive applications but because there was so many sizes and pitches to experiment
with.
Mike M
toggle quoted message
Show quoted text
From: k-designs@... <k-designs@...> on behalf of hanszilver@... [k-designs]
Sent: Thursday, November 23, 2017 12:25 PM
To: k-designs@...
Subject: [k-designs] Re: electric motor experiments
?
?
Hi Bernd,
I actually also looked in these kind of things, but it seems the flex cable gives too much friction, and is probably not strong enough for a 400 Watt electric motor.?
I'm not sure why you think the RC propeller is not good. It works better than a standard prop (the spoed is 6 instead of 4 from a? trolling motor prop), being efficient at the cost of weed shedding and robustness.? For the tiny amount of power available
my?motor does well.
I think the problem with electric boatmotors is that the power (in a? small outboard kind of setup like mine)? is very limited. And if you use "normal" kind of power (say 2 Kw or more) you need big, heavy and? expensive
batteries. The electromotor itself is relatively inexpensive.
I have thought about a longtail kind of thing like you proposed in a private mail, but chose to use a simple, more or less standard setup because of the noise (motor not silenced under water) and the "lack of power unless
you? really go for it and buy a big batterie". The motor setup would then be more expensive as my whole boat, and that is not in balance.
Greetings from Hans
|
Hi. the boat was designed to be offshore capable and Is I'm my opinion. However a catamaran of this size is on the cusp of what you can get away with for extended cruising and live aboard use. I Think Richard woods intimates this for his cruising designs in the 8 -9m size as well. The problem with catamarans is, you have all the space in the world to put stuff, but not the ability to cary it (safely). As opposed to a monohull, where it will take the weight but no space to put it. Having 2 hulls (that are slender enough to perform as a sailing boat) does not add up to great payload capacity Plenty of people put all there cruising gear in small catamarans, but look were the water line ends up. On pictures of Oryx the water line is well above the transoms. The designed fully loaded waterline is supposed to be with the transoms just clear of the water for the KD860. You can pile as much stuff as you like into a small catamaran and it won't sink, but will it still be sea worthy? When you add up the weight of all the gear that you would take for long term cruising, it becomes significant. for example.- Main anchor and rode, spare anchor and rode, fenders and fender boards, shore lines, engine spares, boat repair spares, safety gear, sufficient battery capacity and charging ability to run an autopilot 24h/day, dingy and oars, fuel , water, food, people, peoples clothes and personal items, nav charts and books guides etc, rigging spares, spare autopilot or parts, droge and or sea anchor + warps, stuff to cook on and eat off, first aid gear. And it just goes on and on. So the simple thing to do, is do a calculation on your expected payload that you require, and get a boat designed to carry it, the Kd860 may or may not be the boat for your application. In my situation, I wanted the smallest boat that I could , single hand, do extended coastal cruising, do occasional?offshore passages, afford to build and maintain. And in that respect the KD860 is perfect. For living aboard as a couple and long term cruising on a budget, I think the voyager design would be the choice.? Cheers…... Andrew.
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Re: Intro [4 Attachments]
Bernd:
??? Thanks for the prompt reply.?? Your English is better than my
German from 40 + years ago ;-)
??? I take your weight example to mean an essentially finished
interior, no rigging, to mean no mast or standing rigging, running
rigging or sails??
??? I am the guy who's been casting about for junk rig options on
voyaging multihulls, and focusing in particular on Searunners.? I
find myself single handing more often than not, which is one
reason I intend to sail with a junk rig, and also one of the
primary reasons for a multihull.? The physical stress level is far
lower from what I've experienced on multihulls than on monohulls,
which multiplied by weeks on a passage is a big deal.?? Single
handing is also the reason I want a smaller boat.......?
Unfortunately in multihulls I run up against weight limits that
have forced me both to look at strategies to reduce weight, and to
look at larger boats than I want.
??? The watermaker is really the only reasonable solution for a
boat with limited payload.??? I'm working on drawings and
calculations for two human powered watermakers, which address 4
problems. One being the weight of water, another being lack of
sufficient exercise on passage, another being limited battery
weight, an lastly the questionable quality of local water.?? A
normal human can easily produce a day's supply of water in a
relatively short period of time using an efficient design.?
Ideally that system will incorporate things that you want to carry
anyway.? Half an? hour to an hour of moderate exercise using
pedals or a rowing system........? I personally would not travel
without some sort of bicycle, and it is not complicated to
incorporate a bicycle or parts of one into pumping.? It's not a
new idea. ? Rowing offers a better full body workout, but does not
lend itself as easily to this.. It's more of a challenge, and not
as easily adapted to off the shelf items.
???? Refrigeration is perhaps the most absurd onboard system
behind pumped pressure water.? Ice is a wonderful "battery".?
Where I live we say "make hay while the sun shines".......... To
paraphrase this....."make ice while the sun shines".......? I
needn't say more on this topic really.??
??? Modern electronics, LED lighting and lithium batteries offer
unprecedented opportunities for power savings.? Combined with
conservatism it offers a lot of potential weight savings.
??? To put things in to some perspective here, I've worked with my
hands all my life.?? I've designed and built countless systems,
mostly agricultural, involving mechanical electrical, hydraulic,
and electronic systems.? I'm currently building my fourth
boat........ all small, this being a 15 foot junk rigged sailing
trimaran.? I've done strip plank, skin on frame, and stitch and
glue.? I own welding and machining equipment, obviously know my
way around wood and epoxy, and I build things using electronics,
penumatics, and hydraulic systems.?? It's what I do, and what I
know how to do.? It's my life, and my customers come to me because
I can come up with solutions that work and keep working.
??? Negativity is something I encounter constantly, and while I
listen and evaluate it, it doesn't dissuade me from my course,
though I'm sensitive to the fact that it may point me to things I
had not taken into account.
??? The junk rig is such a situation.? I've been following Pete's
progress from a half assed iteration of the Aerojunk to the soft
wing sails to the current rig, which more or less follows Paul
McKay's original innovative design.? I know about his loss of the
AV panel on Oryx, and installation of mini keels, something I
instinctively dislike on a cat.? It's pretty clear to me that he
is not satisfied with the performance of his biplane rig, or he
would not have gone through these changes.? I've followed Arne
Kerverneland's work on the cambered junk rig, as well as Slieve
MacGalliard's work with the split junk rig, and Paul McKay's Aero
Junk, not to mention the work done on the soft wing sail
systems.?? My current small scale project is intended as a test
bed to determine which direction to go with this.? The investment
in a 15 foot boat is many times smaller than a full size
project.??? It has become very very clear that I have to draw my
own conclusions.... and take full responsibility for the results,
but that's how life in the real world is.
??? They Hedly Nicole / pete? hill? solution of mini keels does
not appeal to me, a multihull caught in a storm needs to be able
to slide sideways, and anything reaching down into "solid water"
beneath the aerated surface, is a "tripping" liability.? Dagger
boards are a problem.... If they hit something, they either shear
off, or damage or destroy the case / trunk.?? Centerboards take up
space in the hulls, in the case of the Searunners, 2 of the 5
major sections of the hull.??? Lee boards present the the problem
of support.......? How do you support them properly?
??? I'm not saying anything you have not spent nights tossing and
turning, seeking solutions to.? You, Richard Woods, Simpson,
Warram, have all wrestled with the same issues and arrived at
various solutions / compromises.??
??? I started with the trimarans....... one mast, one rig.......I
like that.??? The Searunner 34 or 37 has a lot of appeal for that
reason.? Jim? Brown and John Marples are great designers.??? The
'34 is about ideal, but not available for all intents and
purposes.?? The mast must be offset for interior clearance issues,
and I have no real issues with that.? Cats offer two load bearing
hulls, and that means ONLY biplane rigs are viable as far as free
standing junk rigs masts are concerned.?? I plan to live aboard
this boat with no "home ashore", and that is a big factor.? The
small cats caught my attention...... Two load bearing hulls out of
two,? not one out of three.???? I'll probably end up where I
started.? There is no ultimate solution.? Compromise is the order
of the day.
???????????????????????????????????????????????????????????????
H.W.
P.S.? Sorry for writing a "book"........My inclination is not to
go off "half cocked".?? I read everything I can get my hands
on....... that's relevant.
???
On 11/23/2017 11:51 AM, Bernd@... [k-designs] wrote:
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?
So after all I will give my sermon to your questions,
uncertainties to.
I declare the boat as a seagoing/coastal cruiser.
Direct to your question weigth. I would build the boat
with a weight of 1400 kg. First; because of my experience
I know how to built light. Most builders ad unnecessary
weight and when it is smearing the rest of the Epoxy in
the pot somewhere. Example is my PELICAN. I give an empty
weigth of 2000 kg The boat was on the scale of the kran
exaxt 2000 kg. I give always the load waterline, for the
KD 860 with 2800kg. Which means you can add another
1400kg. This is without rigging, deck gear etc.
Distance waterline bridge deck as shown 600 and 700mm
from the cockpit. The bridge deck starts far aft to
prevent to get water (not spray) over the deck. The anti
vortex panels are so strong that almost nothing can break
them. See picture on the Pelican album. We where taking
the boat out the ice because of shifting wind direct. You
c an see in the ice the form from the underwatership with
antivortex panels. We where sailing to windward with these
as any good monmaran ( many persons withnessd this) We
sailed as high on the wind as a "Spectra" from Shuttleword
with big daggerboards. But, here comes the point, the work
not as effective as board in very low windspeeds, and the
chines of the hulls have to be as sharp as cou can make
them. After we added the glass fiber to the hulls (radius
chine 5mm, otherwise you can not get the glass fiber good
around the chine) we added Epoxy with a lot of fused
silica and made "sharp coners " again. All new aircrafts
use the anti vortex panels now again (winglets is the
same). I designed the whole boat for good windward
performance as you mentioned without a deckhouse. Smaller
catamarans crossed the oceans and sailed around the world.
Including a Wharram 6,5m and a Heavenly Twin. The couple
on the Heaven Twin had the bad luck to be in a storm in
the Aguela str eam. Nothing whorser as that. The bridgeck
distance from the boat was by the way full loaden 300mm.
Not cabable to look forward: you gave already one solution
with a dome. Besides when I seat on the table I face
towards the cockpit, and there we have enough
windows/doors made from polycarbonate. Rigging, you are a
great advocate of junk rigs (I belief you are the person
who was looking for a junkrig solution for a Searunner,
perhaps I am amiss). I like junkrigs to. But as from
others mentioned, there windward performance is so la.la
as we say in France. Besides the are very complicated (see
the latest from Pete) with a lot of ropes everywhere. Only
for this reason, the airstream will be disturped. Before
the wind til 45 degree the are great. Now comes the point,
the KD 860 is not slow so the apparent wind will move
forward and you sail almost alwise on the wind. The weak
point of the junk rig. Pete reached with the ORYX 14
knots, but for passages he slowed her down to 7 knots. Of
co urse, then it works.See by the way the picture from his
new rig. In the photo series is a photo from a friends
junk with a semi wing sail he made for 50.000 pesetas.
This sails here working great. This was an phantastic
solution. This was around 1969. He could set the sails by
hand, the floated more or less up. His halyard winch was
green, because he never needed the thing. A tip no big
watertanks, use a watermaker. We had an electric SURVIVOR.
12V, 5 Amps 10 liter water. We had a windgenerator and two
very good solar panels. Was good for all the electrics,
navvy lights, waterpomp etc. Engine, use a longtail drive
with a penger in the mast beam with a Lewis surface
piersing prop (the have props for low speed by the way)
The produce now under an other name, because my friend
Lewis is deat for some years, but you find them in the
Internet. By the way you find here also a solution for
looking forwards. See album 860Fi.?
I was now writing how it was coming in my mind. I k now
there are many English mistakes in, but I hope you get my
gist and I am not in the mood to correct, sorry about
that. At last, I do now somethin I never did before, here
a rendering from a new design, a German customer called it
a "Bohrinsel". Be assured the KD 860 will sail better as
this thing.
Cheers
Bernd
|
Re: Portable petrol tanks?
?Thanks for the replies - clear, practical, and encouraging. Bernd, I was previously thinking of putting the tanks under the aft steps, but then I would have to climb out of the cockpit every time to refill. So there is a good fit in the aft end of each cockpit bench for a 12 gal (45 L) portable tank. That should give us 24 hours of slow motoring in calm conditions (one motor at a time). And more fuel in portable cans as needed.?
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So after all I will give my sermon to your questions, uncertainties to. I declare the boat as a seagoing/coastal cruiser. Direct to your question weigth. I would build the boat with a weight of 1400 kg. First; because of my experience I know how to built light. Most builders ad unnecessary weight and when it is smearing the rest of the Epoxy in the pot somewhere. Example is my PELICAN. I give an empty weigth of 2000 kg The boat was on the scale of the kran exaxt 2000 kg. I give always the load waterline, for the KD 860 with 2800kg. Which means you can add another 1400kg. This is without rigging, deck gear etc. Distance waterline bridge deck as shown 600 and 700mm from the cockpit. The bridge deck starts far aft to prevent to get water (not spray) over the deck. The anti vortex panels are so strong that almost nothing can break them. See picture on the Pelican album. We where taking the boat out the ice because of shifting wind direct. You can see in the ice the form from the underwatership with antivortex panels. We where sailing to windward with these as any good monmaran ( many persons withnessd this) We sailed as high on the wind as a "Spectra" from Shuttleword with big daggerboards. But, here comes the point, the work not as effective as board in very low windspeeds, and the chines of the hulls have to be as sharp as cou can make them. After we added the glass fiber to the hulls (radius chine 5mm, otherwise you can not get the glass fiber good around the chine) we added Epoxy with a lot of fused silica and made "sharp coners " again. All new aircrafts use the anti vortex panels now again (winglets is the same). I designed the whole boat for good windward performance as you mentioned without a deckhouse. Smaller catamarans crossed the oceans and sailed around the world. Including a Wharram 6,5m and a Heavenly Twin. The couple on the Heaven Twin had the bad luck to be in a storm in the Aguela stream. Nothing whorser as that. The bridgeck distance from the boat was by the way full loaden 300mm. Not cabable to look forward: you gave already one solution with a dome. Besides when I seat on the table I face towards the cockpit, and there we have enough windows/doors made from polycarbonate. Rigging, you are a great advocate of junk rigs (I belief you are the person who was looking for a junkrig solution for a Searunner, perhaps I am amiss). I like junkrigs to. But as from others mentioned, there windward performance is so la.la as we say in France. Besides the are very complicated (see the latest from Pete) with a lot of ropes everywhere. Only for this reason, the airstream will be disturped. Before the wind til 45 degree the are great. Now comes the point, the KD 860 is not slow so the apparent wind will move forward and you sail almost alwise on the wind. The weak point of the junk rig. Pete reached with the ORYX 14 knots, but for passages he slowed her down to 7 knots. Of course, then it works.See by the way the picture from his new rig. In the photo series is a photo from a friends junk with a semi wing sail he made for 50.000 pesetas. This sails here working great. This was an phantastic solution. This was around 1969. He could set the sails by hand, the floated more or less up. His halyard winch was green, because he never needed the thing. A tip no big watertanks, use a watermaker. We had an electric SURVIVOR. 12V, 5 Amps 10 liter water. We had a windgenerator and two very good solar panels. Was good for all the electrics, navvy lights, waterpomp etc. Engine, use a longtail drive with a penger in the mast beam with a Lewis surface piersing prop (the have props for low speed by the way) The produce now under an other name, because my friend Lewis is deat for some years, but you find them in the Internet. By the way you find here also a solution for looking forwards. See album 860Fi.? I was now writing how it was coming in my mind. I know there are many English mistakes in, but I hope you get my gist and I am not in the mood to correct, sorry about that. At last, I do now somethin I never did before, here a rendering from a new design, a German customer called it a "Bohrinsel". Be assured the KD 860 will sail better as this thing.
Cheers
Bernd
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Re: electric motor experiments
Hi Bernd,
I actually also looked in these kind of things, but it seems the flex cable gives too much friction, and is probably not strong enough for a 400 Watt electric motor.?
I'm not sure why you think the RC propeller is not good. It works better than a standard prop (the spoed is 6 instead of 4 from a? trolling motor prop), being efficient at the cost of weed shedding and robustness.? For the tiny amount of power available my?motor does well.
I think the problem with electric boatmotors is that the power (in a? small outboard kind of setup like mine)? is very limited. And if you use "normal" kind of power (say 2 Kw or more) you need big, heavy and? expensive batteries. The electromotor itself is relatively inexpensive.
I have thought about a longtail kind of thing like you proposed in a private mail, but chose to use a simple, more or less standard setup because of the noise (motor not silenced under water) and the "lack of power unless you? really go for it and buy a big batterie". The motor setup would then be more expensive as my whole boat, and that is not in balance.
Greetings from Hans
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Andrew:
??? I think you misconstrued my intentions.........or perhaps I
don't communicate very clearly in print.?? When I used the term
"circumnavigation", I did not mean it in the sense of loading up a
huge amount of supplies and racing around the world, I rather
meant that the sailing I would like to do will involve long
passages, such as the Pacific for example.??? Passages that unless
things go very wrong should involve weeks, not months.? I think
I'm hearing you saying that the 860 is really just a coastal day
sailor and weekender, perhaps only suited for trips of a week or
10 days, that nobody in their right mind would consider taking it
on the ARC or the Puddle Jump, etc.????
???? I'm not at all sure what Bernd includes in the "empty weight"
of about 2 tons, or what permanent items must be deducted from the
approximate ton and a quarter of payload.? It would be interesting
to know what the real world weight of one of these boats is with
no supplies, spares, food, water, fuel, engine nav and radio
equipment, batteries, solar panels, pretty much just the bare boat
& rig & sails, with just basic interior fixtures such as
cushions in the berth area and saloon, a C-head, basic galley sink
and stove.
??? Two tons (1800 kg) is not a lot of boat............. if by
contrast one looks at Richard Wood's boats, foot for foot, they
show heavier weights, and lighter payloads.?? My suspicion is that
the two designers are listing empty weights that are not exactly
the same meaning, the result being that Bernd's boat has the
appearance of having a much greater payload.
??? Pete's boat as you know was stretched to 10M (33 feet), a 16%
increase in length over all, but it apparently easily carried all
necessary supplies for two people for the sort of voyaging I plan
to do.?? I presume that the increase in the size of the bridge
deck cabin, and the weight of the biplane junk rig, probably
resulted in no or very little increase in actual payload.
??? I won't argue the merits of the junk rig here......... That's
pointless, except to say that Oryx is obviously seaworthy with a
biplane junk rig, so obviously it's doable.
??? As far as basic design, Bernd's gotten everything right in my
opinion for a small economical seaworthy cat, from the flat hull
bottoms to the unbroken curve of the cabin top, to the bridge deck
clearance, and less than standing height in the saloon, where you
normally sit anyway.?? The KD860 and it's variants make all the
right choices in my opinion.??? As someone who is primarily a
single hander, it appears nearly ideal.?? I've had a belly full of
monohulls.? There is a better way, but the challenge of making a
cat work well in small sizes is not small challenge, and Bernd has
done what in my opinion is a very good job of it.
????????????????????????????????????????????????????????????????????????????????????
H.W.
On 11/22/2017 04:57 PM, andrewklees@... [k-designs]
wrote:
toggle quoted message
Show quoted text
?
Hi. I mean no offence, but the type of boat you describe
only exists in an alternate reality.?
If you want load carying ability and pleasant motion to
windward, a monohull is the boat of choice.
If you want to circumnavigate in a catamaran, 8.6m is
too small when you consider the required payload.
If you want safety in a multihull, performance is a
priority unfortunately. light weight, windward ability
etc.
Installing a junk rig on a boat not designed for it, is
a major engineering exercise. But if installing dagger
boards after the fact is unappealing. how are you going to
cope with the amount of design modification and
construction work that would be required to turn this
stock design into your dream ship?
As for bridge deck clearance the kd860 is textbook @
approx 6% of w/l length @ the lowest point and more under
the cockpit, were you need it most, how much do you
require?
As far as I know Pete Hill is using mini keels, and had
one fall off, with no noticeable difference, not the AV
panels.
As for your rig, I don't want to weigh into the debate
about efficiency, however your modern cambered junk rig is
going to take a huge effort to design, build, and get
working properly, as opposed to installing an bermudan rig
with essentially off the shelf components. It certainly is
something for the very motivated enthusiast.
I don't won't to appear negative, but as they say, all
boats are a compromise and the one your after is not the
Kd860 or perhaps any mulltihull that would be seaworthy.
I own a Kd860, and although I am very happy with it's
performance, it certainly won't do what you want, from my
experience.
Anyway, good luck with the design hunting.
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Re: Portable petrol tanks?
I have a 37foot cat with lifting outboard(s) and have made ocean passages. The tanks do require occasional changing and re-filling at sea that I try to do in calm conditions and try to only motor in calms with the outboard(s) up when it is rough. I put a gerry can on the cockpit seat above the portable tank and use a siphon hose to fill the portable tank at sea.? The siphon hose unit I have has a copper fitting with a marble inside at one end with a 6foot x 1/2" diameter hose attached.? To start the siphon the marble end of the hose is put to the bottom of the full gerry can and jiggled up and down a few times to start the siphon and lifted out of the gerry can when I want to stop the siphon.? There is no spillage unless you allow the tank to overfill. I carry a couple of these units, one for water and one for fuel, as they are light and only cost $10-15.00 each. They are variously called: Shaker Siphon;, Moeller Siphon Pump; EZ .5" x 6" siphon hose; Shoreline Marine Easy Shake Siphon Hose, etc. Available at Canadian Tire, Walmart, etc. I have been using these for fifteen years and the only maintenance is to change the hose every five years or so as the fuel eventually hardens the hose. I wouldn't go cruising without them. Paul Howard
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and here the next pictures from Harald. The keel is now covered with Keflar, with some usual problems with this stuff. ?He used glass fiber strips to tame the material. Was you ever trying to sand a piece of cloth? same effect, impossible.He lives in North Germany and his sailing area is the Wattenzee. So dry falling is a normal thing for him. Of course, Keflar gives good protection.
Bernd
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Re: Portable petrol tanks?
Separate the aft part of the cockpit benches and store there the petrol tanks. For good ventilation drill big holes in the bridge deck.?
Bernd
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Re: electric motor experiments
and here a solution?
adding an electric drill, perhaps it works and would be cheap. The drive costs a mere � 70,-
Bernd?
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Re: Portable petrol tanks?
Hi Patrick. Yep theres no problem there. As previously stated, separate system for each motor and tanks in well ventilated area are the go. On my single outboard set up, I use 2 x 45l tanks plumbed into 1 fuel/ water separating filter. The filter has 2 inlet ports in it and I put a small ball valve in each port to select one or both tanks. Works well and did not cost much. There is a large selection "portable" fuel tanks out there. I personally would install the biggest ? ones that will fit in the space you have. After all you don't have to have them full all the time if weight is a problem. As for size, you might want to do some calculations in relation to fuel load and intended usage, before you get too carried away. The down side of petrol outboard motors in relation to diesel motors, is they can be thirsty. My 25hp high thrust yamaha gives 6.5 - 7 kts in calm conditions @ about 3.5 - 4l hour (1/3 - 1/2 throttle) in the Kd860. I think it uses about 9l hour @ full throttle. Does not sound like much, but if theres no wind and you have a long way to go, it soon ads up. Cheers..Andrew.
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Bernd Kohler