again see private replay
Bernd
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hello Bernd.? if I understood, ?the kevlar is laminated alone. ?it means no fiber glass applied under or over the kevlar.? Is it right?? The only place fiberglass meets the kevlar is on overlap area! Correct??
One question.? Should I use the kevlar only on the flat area (keel) or it should be extended to the chine??
No fiberglass lamination on the inner side of the planks.? Correct??
Tks again Bernd.? Fair winds
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see my private replay
Bernd
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hello bernd,
i just bought the kevlar you suggested in order to allow me to beach the cat without much worry.
At the moment i am preparing to plank the first chine of the first hull. (it took longer than expected because rainy days had set in my region)
Some questions came up to me now.
here i go:
Considering i want to use the KD1000 for offshore passages, should i consider to make any structural reinforcement?
for a moment i was thinking about laminate the interior of the chine planks. Just wondering that it's? an area wich is permanantely "inside" the water while on? mooring.
Is it make sense or it will just add extra weight without benefit?
Thanks once again Bernd.
-- Thiago R. P
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Re: Eco 5.5 Sailing Version
Hi Hamish
Life is full of coincidences and those 6 steps of separation stuff.
With so many contributers, I think you can be excused for not knowing where I'm from. ?
Like many, I started out sailing dinghies in Sydney as a kid and moved to yachts after uni. ?I moved inland to Canberra and didn't sail much there - far too flukey although I did take one trip nd down the coast between Tassie and Jervis Bay when I was finishing up working for the Navy. ?I've been up here for 20 years now. ?Most of my sailing since has been delivery trips up and down between Southport (Gold Coast) and Sydney or Southport and Hervey Bay. ?35ft glass cats. ?Very nice very fast very big. ?Like sailing an appartment. ?Totally scary at 20kts down a wave, although apparently safe.
We're right on the Pacific Ocean so not great if you want sheltered small boat sailing. ?I bought Bernd's plans for the 650 thinking that if I got caught 'outside' (which is basically 25 metres from home) I would have some level of stability. ?I did not think that the Richard Woods Chat that I also have plans for would be as forgiving in a blow. ?I got them thinking that Linda would like to come sailing again - wrong again.
My intention (subject to female over-ride) is to take ocasional forays up and down the coast from Ballina south to Evans Head/Yamba, or north to the border (Tweed Heads/Gold Coast). ?Ballina does have a river, but it doesn't offer a lot of scope without the need to drop the mast for low bridges. ?I have actually spoken to Bernd about lessons from his experiences in Holland where they seem expert at dropping masts and popping them back up the other side of the bridge. ?Just the same, I think the better approach is to wander up and down the coast according to the weather.
I'm not doing any sailing at the moment. ?Nor building. ?My partner Linda seems to have found a mass of projects to keep me away from the shed - well, not quite. ?If I need to use the table saw for some reno project on the house or caravan, that is pernitted. ?I exaggerate of course.
Our kids have all left home years ago and 50 is a birthday ?I had a long time ago.
I do hope to get into bulding the 650 or 'something' soon. ?Meanwhile I move to the next project (a chicken coup of all things at the step daughter's country property) and watch you build and chat to fellow dreamers. ?And every now and then I buy more plans thinking some day I might actually start using up my epoxy and boat fittings
cheers
col
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Re: DUO 105 Nacelle, and hull attachment questions
Hello John
Thank
you for your interest on the KD 105 (nee DUO 105).
There
is general nothing special necessary for the construction of the KD
105. Plywood for instance Okume WBB is alright. You can get the good
material at Jouber outlets. Joubert was buying Brunzyeel years ago.
Epoxy, the same it is what you like. Today you get also non toxic
Epoxies for reasonable costs.
The
beams are a different issue. We use mast sections for beams, because
these are the most cost efficient and have the right quality. Reason,
the are more easy available as tubes with the correct strength and
for reasonable costs. So we use for the mast beam and aft beam mast
sections. Example mast section, SPARCRAFT from the ocean series S
2390, dimension 165x315 mm length 6200mm. But any other mast section
with the same strength will do. Now, after the Hurricane disaster it
will be easy to find from a discarded boat a mast part which would
fit. The unlucky owner will be happy to sell you an otherwise useless
mast. Same for the aft beam (other dimension but shown in the plans
set. For all Aluminum beams, also fore beam with gull striker, mast
beam with dolphin striker and the aft beam recommendations and actual
measurements are shown in the plans. The welded fore beam connectors
on the hulls are made from 3mm sheet stainless steel material.
Dimensions are given in the plans. Otherwise no special materials are
needed for the boat.
The
mast stands in a normal mast support you get from your mast maker.
These is mounted instead of the deck of the boat on the top of the
nacelle. The boat has to be mounted on the wall. Then the boat is
launched and the mast set as with any other boat. With such a big
mast, to set the mast a crane is advisable. The owners on the
Philippines and in Australia do it this way. I can design a device to
set you can set the mast by. Here in the Netherlands it is we have a
lot experience with this system. But the mainstay mounting point has
to be level with the turning point of the mast step for side wise
support when rising or lowering the mast. The boom would then be
used as lever to set the mast. Extra strengtheners and stainless
steel tube constructions on the hulls would be necessary. This would
cost extra weight and I have to design them. An extra fee for the
design would then follow of course. I think a crane is the logical
solution.
By the
way, I never heard from the boat which was/is under construction in
the UK. It was a student project from the University of Southampton.
I lost also contact with the owners from the other two finished
boats. That is the way it is going. The design is from 2010.
I hope
I could answer your questions to your satisfaction. The boat is
extreme fast what I was hearing, but no data.
Cheers
Bernd
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DUO 105 Nacelle, and hull attachment questions
I'm very interested in building the Duo 105. I have built in the ?WEST system and Brunzyeel marine ply before. I have overseen the construction of hundreds of homes here in San Diego. I have the property and a great climate to build in.
My last catamaran was the 55 foot Lagoon, built in the advanced techniques racing yard of Jeaneau in Nante, out of vacuumed epoxy, kevlar and carbon fiber, she was just a superb wind machine.
But I am fascinated by Bernd's combination of seaworthiness, simplicity and speed in the Duo 105. Our wind speeds here in San Diego average about 10 knots for 350 days a year. - SO - having a cat that can sail 10 knots in what is our usual wind speed will be a great thing !!
I have used the study plans to carefully source out and accurately estimate the materials cost. My problem is that the study plans do not explain what I think are construction items that are completely unique to the Duo 105 design.
I hope that my questions can be answered by someone who has built, or is in the process of building the Duo 105, or perhaps Bernd could answer my questions. I am new to this group, but am happy to pay a consulting fee Bernd, as needed.?
- THE NACELLE AND MAST SECTIONS - Can the mast sections that run through and support the nacelle be removed from the nacelle in order to transport the boat ? I am sure this must be the case, but this is unusual, and I would like a general overview as to how this is done. - Are the two hulls connected to each other while they are afloat, with the mast sections while they are in the water, after being unloaded from their trailer on the boat ramp? - Will a crane be needed to raise the mast after the boat is assembled? - Has the Duo 105 been built ? Are there photos of the construction ?
Thank you in Advance for Your Response !!
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Re: Eco 5.5 Sailing Version
Hi Col,
sorry so many contributors to keep track on, I forget the back stories. Most are in the Northern Hemisphere. Yes we have been watching on the nightly news the record highs across the ditch.?
I spent a couple of years studying Woods designs and even bought the full plans for the Wizard and the Sango. But they were too big for me and a more complex build to my mind. When researching I too came across the work by the Scottish builder, he had the right idea making it a fixed beam and not worrying about the folding mechanism, they sit so high on a trailer I would be terrified to tow it around.?
I was really worried about the beam of the Eco 5.5 thinking it looked narrow for the length, but Bernd really knows his designs and it is so solid and feels very stable in a breeze. I heard the Jarcat was prone to capsize due to the beam, but I guess it can come down to sailing ability and knowing the limits. I have 2 reef points and plan to use them! We get plenty of breeze in the Bay of Plenty.?
Gagging to get out again but must contend with work, family and chores around the home put off for the last 2 and a 1/2 years. I have promised my wife and kids 2 years before I consider another "project" by then the half century will be almost upon me and I may need a focusing project to see me to retirement!?
I see it is open water where you live, is that your sailing ground??
regards
Hamish?
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Re: Eco 5.5 Sailing Version
Hi again Hamish
I'm sure that those in the northern hemisphere would love to get out of the deep freeze ASAP, but I'm not one of them. ?I'm in Lennox Head near Byron Bay sweltering in about 35degrees. ?I am looking forward to some cooler weather though.
I mentioned the ebook because I once read (and bought, but just for a few dollars) the story of the Cornalari Wizard. ?I bought the book because I wanted a bit more of the ins and outs of the build process of a design I was considering at the time.
It's the story of a chap in Scotland who built a Richard Woods designed Wizard folding catamaran. ?His version was made NOT to fold but that's another story. ?The story was all about his building process and a tiny little bit about how it sailed etc. ?Like the chap who built Sparta in NZ, he also had a blog. ?The blog still exists, but there hasn't been any action on it for a while.
Ah yes back to school. ?We had a principal friend of my partner's drop by for a few days last weekend. ?She was not at all looking forward to getting back into the front line with students and parents (and the department).
cheers mate
Col
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Re: Eco 5.5 Sailing Version
Hi Col,
Happy New Year and thanks for the compliments. An e book! yes that is tempting. I have put a photo book together for myself and my Dad but only with captions. Not sure what the general public would want to know from my experience. I once wrote an article on building a Hartley 14 yacht and focused on the time and cost elements as I always read with interest the hours spent building and the cost. As I suspected builders liked to understate both. But I did conclude dollar per hour its a dammed good rate to have so much fun. I am back into school to prepare for the coming year and so will most likely not get far with an e book. I did promise to provide CAD plans for the trailer and will get that done first. Hope spring comes early in the North and you can get back building!?
Regards
Hamish?
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Hey Chris, I lost contact with you. Did you make it through the snow and ice ok? Feel free to email if you still want to plan a visit. voya12m at yahoo.com Patrick
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Re: Eco 5.5 Sailing Version
Hello Robert
Good,
this is the logical way to go for you.
Having
the luff board on the inside under the bridge is here the trick.
Because, and now it comes why you have to ¡°square¡± the top part
of the board. The round part would be a point load and a lot of
stress on the bolt. Now is the bolt more or less only the turning
point. The main load spread over the flat area. On the hull and
board. When you cover the areas with a layer of gravit (pouter)/fused
silica and Epoxy the work as a big bearing area. This is the reason
why to make the part square.
When
you use wedge shape sanded plywood pieces and glue the pieces to the
board the work is quickly done. Use a lot of Epoxy glue to glue the
pieces to the boards.
The
bolt is only a turning point, because of the squaring of of the upper
board part. The 2 stringers give a big area to spread the load.
Important is to use big diameter washers to spread the load. At thick
fillet on each side of the stringer will be also advisable.
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Re: Eco 5.5 Sailing Version
Hi Bernd,
Thanks for your advice! After some more consideration, I will build luffboards for my ECO. My main consideration is reduced risk of damage if a board hits the ground at some speed.? Also, I prefer the G¨¹nter rig and I understand that this requires luffboards.. And of course, I take your advice to make a luffboard for each hull (otherwise it wouldn't be a luffboard anyway :-))
This decision being taken, I have some questions on the construction details of these boards.?
1. How, and from what material, is the rounded top part of the board to be made?? 2. You state in the building description that "For about 400 mm the upper part of the board must be square". From what I understand, one first has to build the entire board as a wing profile and then add an extra layer of material on the top 400 mm to make this part square. As an amateur, building my first boat ever, I must say I am baffled. It seems cumbersome to me to first build this part as a wing profile and then making it square again. Could you explain a bit more in detail how this is to be done? A more detailed drawing or, better, some pictures from a project would help me a lot... 3. Since the boards can be subjected to a lot of force, I guess their attachment point to the hull (the M16 bolt) should be sufficiently reinforced to take this load. However, in the drawing the only reinforcement I find is the doubling of the stringer between BH 3 and 4. Is it not necessary to also reinforce the planking on this sport, for instance with an extra layer of plywood, or maybe with some carbon fiber + epoxy on the inside??
Thanks for any useful information!
Best regards
Robert
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Re: Eco 5.5 Sailing Version
Hi Robert
Hamish has given I think comprehensive information about his adaption of boards. As everything in life, chaning one thing to the better will change an other to the worse besides for a boat in a given sice. By the way, I design boat a bit longer as yesterday. So when you had the plans you would see that there is an aoutside stringer at the areas between the dagger board. For a small catamaran as the ECO 5.5 I am strictly against having a board only at one side. I outlined way some letters ago. If the board is on the wrong side it helps to turn the boat over. I think from you was also the question about sail makers in Europe. I have no clue, or I buy where it is the cheapest at a given moment in the world. Or I make them myself.? So in the end ?my advice have on each side a leeboard with some bungee arrangements for automatic dagger board kick up. The a-symmetrical daggerboards are quicker to build and are more effective.
Bernd
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Re: Eco 5.5 Sailing Version
Hi Hamish
I have probably said this before, but I really in awe of what you have done in your build. ?I am not too shy to say that no way and no time could I replicate your effort. ?A fantastic job and your explanation of how you went about it in such an organic way makes quite ?a story. ?I can feel a new ebook coming into creation as well as the vessel you've made.
Congrats and happy new year.
cheers
Col
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Hi Bernd,
Would you also have an advice on any european sail makers?
Best regards? Robert
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Re: Eco 5.5 Sailing Version
Hi Hamish
This was a very intersting letter. Perhaps one board on side would be sufficient. With the trade that the boat would be unstable when the board is on the leeward side. For a relativ small and lightcatamran a handicap. But I think for what you wanted the best compromise. Interesting is your observation that the boat also on a reach would sail sidewise with the boards raised. The underwater area of these light cats is very small, so there is no grib in the water. I hope the low will pass quick and that you have a nice sailing weekend. The last days we had your typical winter winds. But it was for the first time that my boat on the trailer was blown in my terasse door., the wheels where on the part on the gravel by the way! I write this letter sitting outside in the sun with + 20 degree today. This is our winter weather here. I am pleased not to life in the Americans and wish the people there, keep warm.
Cheers
Bernd ?
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Re: Eco 5.5 Sailing Version
Hi Hamish,
Thank you very much for your comprehensive explanation! If you have to regularly sail through shallow waters I understand your need for a form of drift prevention that doesn't go too deep.
In fact, I have the same problem, as large areas of my intended sailing area (Lake Balaton in Hungary) are very shallow. In fact the waters all along the south coast are very shallow, reaching a depth of over 2 m only at 500 - 800 m from the shore.?
After your explanation, your solution of using two centerboards, both in the water at the same time, is not very attractive to me, mainly because of all the extra work it involves. I would like to keep my boat simple and reduce work as much as possible so I can start sailing sooner :-)
As it is my first boat, it will be far from perfect, but that is OK with me. After having built this one I will have gained a LOT of experience and I might just start building a new and bigger boat all the while sailing with this one...
But to continue with the problem in hand: what I am worried about is not so much sailing efficiency with a daggerboard only partially extended, but what would happen to the boat if the daggerboard were to suddenly hit the sand at relatively high speed. I am afraid the daggerboard case could be torn loose, causing heavy damage to, as well as a large leak in the starboard hull.? ? So now I am considering to use the lee or luff board(s) Bernd proposes as an alternative.? I am fairly sure these would handle hitting the ground elegantly, by just turning upwards without generating dangerous stresses in the construction.?
However, in order to reduce work as much as I can, I would prefer to fit just one board instead of two. Of course, in that case, I would use a symmetric profile instead of a wing profile as proposed by Bernd.?
If you or anyone else has any views on this I would love to hear from him (or her).?
Here the sailing season is still a few months away, with a violent storm raging over the Alps just a few days ago. Some hapless skiers had the fright (or the fun?) of their lives, see the following short clip: https://www.facebook.com/Wetterwarnung/videos/1603618316397807/
So enjoy your good weather while it lasts. Have fun!
Robert
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Re: Eco 5.5 Sailing Version
Hi Robert,
My reasons for 2 boards was I wanted less draft due to our shallow habour where I sail. I figured 2 would allow a similar wetted area without having to go so deep. Ironically I made them so long they are as deep as the single board if fully down. At the time Bernd commented with 2 boards they could be asymmetric to help the lift. I had made them before I told the forum of what I was doing. (better to ask forgiveness than permission!)
Second thing I did was changed them to be plumb straight up and down. Reason we have a terrible buildup of algae during the sailing months, its green and is known as sea lettuce long and stringy, I could see it riding up the forward facing board and lodging against the hull. I hoped but have no proof that straight up and down would reduce this possibility. We do sail center board yachts happily all summer so its maybe not the issue I perceived it to be.?
The changes moved the centre of lateral resistance so Bernd was kind enough to reconfigure the mast position to allow for this. I am very grateful to him for that, it moved 300mm forward.?
I got the idea of placing them against the hull from a design called the Jarcat, an Australian design of which 100's have been made.?
I encountered many unexpected issues by doing this. Firstly the side of the hull has a flat along it as I inadvertently pulled on the stringers when gluing in the case, maybe I should have shaped the case to match the fair curve of the stringers. That was the least of my troubles. I realised once the hulls were turned that I would have no show of raising and lowering the boards from the cockpit without some form of overhead gantry with blocks and cords, weight, wind age and not pleasing to look at. My solution was a little radical, I decided to create a side deck so I could stand over the board and lift and lower them, in practice this has worked very well. It was an organic process, just got some timber stringers and saw where the natural flow was, it kind of goes in and then out, made for a bit of a compound curve to the cabin sides. Which I also messed with and created a little chamfer at the top. Of course there are trade offs, lost internal space in the cabin, now a very tight squeeze to sit on the toilet as no longer the shoulder room (and I am not a big man!), also had no idea how I would sheet the jib as the hatch now covered the entire port side of the cabin top, only luck meant the chamfer proved to be an ideal place to put the jib track and jammer.?
Putting the center case where I did increased the space internally as I don't have the bulk of the case coming through the cabin. Also for me when returning to shallow water I can lift both boards and they do not get in the way of the boom, something that concerned me about the original arrangement, as I may need to sail down wind to get into a bay and the board up looks like it would be in the line of the boom.?
After I have sailed a little more I will probably take to the centerboards and shorten them, it will make them lighter and even easier to manage I hope. I just want to play with it over summer and see if I can identify an ideal draft for upwind work. They are efficient, when coming into shore I was on a reach and as I lifted the boards we stopped making way and sailed sideways, of course by that time I could jump off and wade or as we did start the motor.?
So in summary loads more work, with issues to overcome. For where I sail it was worth the effort and I personally love the clean lines and out of the way nature of the arrangement.?
I hope to get out sailing this Sunday, we are experiencing a tropic low causing flooding, wind and rain in the region (we are fine on our hill over looking the habour), but it is forecast to blow over by Saturday and Sunday should be light winds and sun. Some significant snow and cold is been reported on our nightly news in the Northern Hemisphere, I hope all subscribers and families are bearing up well, I can't imagine what those conditions are like!??
Happy New Year all
Hamish?
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Hi Jens I once was tasked with developing a process to attach potted fittings to Vectra-fiber rope for undersea use. Potted fittings can be bought off-the-shelf for wire rope. The wire rope is passed through the fitting and then splayed out. It is then drawn back until flush and epoxy potting compound is poured into the tapered fitting. The main problem was that most synthetic ropes, including Vectra, are made using silicone lubricants. These lubricants are extremely difficult to completely remove.
My recollection is that our best results were obtained using Xylene to remove the silicone lubricants. However, our best was only 60% as good as a simple eye splice.
I think you should just take Bernd's advise and use what has worked for him in the real world. We could spend forever talking about the nuances of materials. But my intention was to point out there are better alternatives to sacrificial keels. Bernd is aware of this and has real-life experience and practical solutions.
David
From: "shakalboot@... [k-designs]"
To: k-designs@...
Sent: Thursday, January 4, 2018 2:00 AM
Subject: Re: [k-designs] Re: beaching keel
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Hello David,
Thanks for your comprehensive answer. I knew that the strap material I found were made of polyamide (I read the differences).
Many years ago, I had been driving model car racing. To increase the impact resistance of the axle parts, we "simmer" these parts in water (~ 85 ¡ã C) for about 10 minutes. The axle parts were also made of polyamide (Miramid)
Yesterday I searched further and found strap material made of polyester (https://www.naehkaufhaus.de/Sicherheitsgurtband-Autogurt/Autogurt-schwarz-46-mm-p830.htm).
A "small" problem remains the possibility that the polyester yarns were treated with silicone oil ...
I work as a painter; to degrease the surface I use the industrial silicone remover - would that be a way to remove the silicone oil from the polyester fabric? At least the biggest part.
My idea: Silicone remover with a spray gun (high pressure)? through the belt material blow through and remove most of the silicone oil.
Polyester should be resistant to silicone remover, or not?!?
Certainly, my compound (polyester webbing and epoxy resin) is not comparable to the load of industrially manufactured polyester composites, but I think it is sufficient for the protection of the keels of my multihulls.
I will apply the straps to the keels in the vacuum infusion process.
I think, the material thickness of 1.5 mm will provide sufficient protection with a "possible" ground contact.
I do not want to drive onto the beach or of stones all the time.
Thank you very much und best regards,
Jens
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Bernd Kohler
Robert Twiss