Printing props, so nice! I’m very interested. For now I tried several model airplane props and got nice results, better than original prop.?
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Op 29 jun. 2021 om 17:44 heeft nightline@... het volgende geschreven:
?Hi Günter,
I have an 3D printer, but it is maybe to small...
It's one of the first LeapFrog printers.
If you have an STL for me, I can try to print one.
You can email the STL file to: nightline_hetnet.nl.
The underscore needs to be replaced by @
Groeten, Jack
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But you can do some good thing with 3dprint?
Here my clamp and i built my 10x5feet cnc machin?
Envoyé depuis mon appareil Galaxy
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-------- Message d'origine --------
De : "Stéphane Blanchette via groups.io" <stephane@...>
Date : 2021-06-29 12 h 46 (GMT-05:00)
Objet : Re: [K-Designs-Multihull-Sailboats] COVID-19
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Ce courriel provient de l’extérieur de votre organisation mais affiche le nom d’un usager interne. Ce type de courriel peut être utilisé lors de tentatives
d’hame?onnage. ? moins d’être absolument certain de la validité de ce courriel, veuillez l’ignorer. – This email was sent from outside your organisation, yet is displaying the name of someone from your organisation. This often happens in phishing attempts.
Only interact with this email if you know its source and that the content is safe.
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Many have around the globe?
So for you will be easy to find locally one have 3d print
But be honesr i have one and don t expected more from 3d print?
For testing prop.
As 3d is laminated not cast so very brittle plastic
Envoyé depuis mon appareil Galaxy
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Many have around the globe?
So for you will be easy to find locally one have 3d print
But be honesr i have one and don t expected more from 3d print?
For testing prop.
As 3d is laminated not cast so very brittle plastic
Envoyé depuis mon appareil Galaxy
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Zee, I am very happy to see your DUO 800S is progressing nicely. I was particularly thrilled to see some photos of the cockpits and companionways. This is a portion of the design that I have been contemplating since I purchased the plans and it was a main selling point for me because?of the protection it affords from weather being a New England sailor. I have not gotten any farther than a model of my vessel, and the pragmatic half of my household informed?me that one of our three other boats would have to go first, oh and then there is finishing my 133 year old farm house... Wishing you the best with your project, and looking forward to more photos.
Scooter
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Hi Günter,
I have an 3D printer, but it is maybe to small...
It's one of the first LeapFrog printers.
If you have an STL for me, I can try to print one.
You can email the STL file to: nightline_hetnet.nl.
The underscore needs to be replaced by @
Groeten, Jack
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Hi Jack,
I've more or less bought the same motors and planning also to tinker my own outboard drive with some parts of conventional outboard legs. But this project is postponed now, as I will try to get my boat on the water this year before end of the season (really don't know if it will happen). So I will start with little Haswing outbords (1,44 kW each).
Regarding the propellers: a year or two ago I wrote a software tool, which calculates the shape of a propeller using parameters I put in. It's the parameters published in the dictionary of the International Towing Tank Conference (? pages 53 ff). The tool generates a STL file, which can be printed out by a 3D printer. Printed plastic propellers are really working but will have not very much lifetime. My thoughts were to print some propellers (its just a klick from right hand to a left hand prop) with slightly changing parameters and do testing to find out which prop suits your drive and boat best. After that the known prop shape could be produced e.g. in metal.
As I have no 3D printer I'm looking for an interested guy for cooperation.
Gru?, Günter
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Re: Power ECO 85 Electric
Hi Jack, like me you are going solar. So I presume you are interested in not wasting electric energy. As internal combustion engines and their fuel are cheap the producers of this equipment did not invest much effort to avoid energy losses .  The attached curve shows that a motor efficiency of 80% an better is only possible in the motor rpm range between 4400 rpm and 2000 rpm. After reduction it will be around 2300 to 1000 at the prop. The hydromechanic efficiency of a prop is the better the slower the prop turn and the larger its diameter is. And prop losses are usually the largest losses in the drive train. (Regarding props I wrote an answer to your post in the Covid thread.) Gru?, Günter
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Re: Power ECO 85 Electric
Gents,
For my e-drives I've Golden Motor BLDC motors which are 3 Kw continuous and 5 Kw peak.
These will be connected to Suzuki DT6 bottom ends with pin-drive, which have a gear ratio of 23: 12 .
Without modifications on the bottom end I can mount a 77/8 inch, and the highest pitch I've found is 7,5 inch.
Is this prop the right one, or do I need a higher pitch and / or bigger prop?
Thanks in advance!
Jack
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Hi Bernd,
I've not worked much on the interior last time, but concentrated on the roof and foam corner between underside bridge deck and hulls.
When I have things to make, and don't know how to do, I leave it till I got an idea.
For this reason it took a long time before I made the foam corner. I've made this from blocks of foam, cut it to shape on table saw and glued it in place 1 meter at a time.
Regarding the E-drives: I've bought two Golden Motor BLDC motors which are 3 Kw continues, and 5 Kw peak each. These will be connected to the 2 used Suzuki DT-6 outboard bottom ends which I bought. I doubt if I and how I build or buy the middle section between the bottom ends and the motors.
It also seem to be difficult to find high pitch props which fit to these "pin-drive" bottom ends. I prefer a left and a right hand turning prop, but that's even a bigger challenge.
Time will tell what I will do.
First I want some paint on the boat, so I can install the windows, and after that the roof on top of the windows.
Regards,? Jack
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Hi Zee
You are going well. I see, this is not your first boat. I like your standard of quality!
Cheerd
Bernd
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Hi Zee
Thanks for the photos. I see Covid 19 did not affect you. In your country it was handled very well.
Very nice progress. So funny, every builder of my boats is surprised how light they are. If correctly built, and yours are,
they are?as light as any so-called "super light" sandwich construction. Only a lot cheaper and faster to build.
Good idea, to use the space besides the dagger board case as water tank.
Cheers
Bernd
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Re: A few questions about the minicruiser 480.
Hi Michael
everything the above contributors to your questions are true, and yet in some cases a little contradictory. This is because we all have different levels of ability, we have different levels of comfort requirements, and we have wives with different levels of fear.
Add to that the more practical questions:
What is our boatbuilding experience?
What access do we have to specialised boatbuilding supplies? (I have got one of the Americas cup spar fabricators within a 20 minute drive - lots of offcuts and bargain spars)
How far will we traIl the boat to our favourite sailing grounds, and what are the roads like in doing so?
Realistically, how often will we actually use the boat for extended cruising?
If I can add my own reasons for building the Duo 480 it will show how? it suited me the best.
I was keen on Bernd's KD650 but concerns of assembly time made me hesitate. Rodney built one locally and kept it on a mooring. I sailed on it many times and it is a wonderful boat, but assembling it for a day sail would have been impractical.
I knew day sailing with a degree of protection and shelter would be my main requirement and so I built the Duo480. It is very quick to rig with the bi plane rig, can be reefed in a few seconds, and doesnt need a big motor - i use a 3.6 hp. The boat is light enough to beach launch which is my favourite method. With custom made sails it is a quick boat.?
If I? was building again and I wanted to moor my boat, I would build the Eco 6. I saw David's boat during construction and was very impressed with it. I also visited a local 5.5 builder several times and that boat is also a very nice boat. Both are a lot bigger and bulkier than the Duo 480 and would be more of a handfull to trail regularly. I did build mine to 2.5 metres wide so it has maximum legal local trail width.?
You have to decide in the end which model you will get the most use out of.
?Just my thoughts, kind regards, Bryan Cox
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Re: A few questions about the minicruiser 480.
Thank you for chipping in.
Rememberings. The last time I was sailing in San Francisco was in 1983! I remember the wind. When there was no wind in the afternoon, the weather would change. The same phenomenon we have on the step coast areas on the Med. A reason, why we have so many power boats here. They start early to be before 2 PM at their destination. After around 2 PM, the wind starts very quickly. Near the coast, after a cap, the wind direction can change from an on the wind course to a before the wind course. The result, cross waves. But as you describe, it is, in the end, a question of good seamanship to handle this. That it can be uncomfortable in small boats is clear. But when you know what you do, it can be handled. Sailing the tidal waters on the Dutch coast can be also, say, interesting. Names of places like Hellevoetsluis (hell-foot-lock) indicate this. Not funny in high wind and the tide against. Steep and high waves. Again, we sail there regularly also with small boats. Now a bit of advertisement, not one from me designed boats was in trouble in such situations. No matter, from the SC 435 till the prototype Butterfly, or later the Manta and Pelican. Not to mention the Zeeman. So in the end, it is up to everyone what he wants and is ready to spent money-wise and time-wise.
Bernd
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Re: A few questions about the minicruiser 480.
Michael, I am surprised by your advise for 25-knot winds and 3-ft seas.
I spent 20-years sailing in San Francisco bay where summer afternoon winds are often 25-30 knots. With practice and good reefs these conditions can be very sail-able. I sailed the conditions with catamarans, open dinghies, racing dinghies, small and large keelboats. When I used to teach sailing, I always advised my students that in significant winds, sails are more powerful than engines and more dependable. Sailing with my family, I would often put my wife or kids on the helm and then throw a bumper over the side for them to retrieve. Even 7-year old kids can maneuver to recover with practice in 25-30 knot winds. My point is that well designed boats can maneuver well in 25-30 knot winds if the sailor takes time to practice in those conditions.
3-foot significant waves (i.e. 1/3 highest wave height = 3') is really quite large. It means the highest wave is near 9'. Wave height is defined by seaman's observations. So 3' significant wave would be defined as the average wave height observed by an experienced seaman. Just knowing the wave height without the period doesn't show the real picture. Here in the Pacific where we have no continental shelf waves can be very long. Even the smallest boats can be comfortable in 10' waves when the period is 15-seconds.
I know that the Gulf is shallow water so wave period will be short. San Francisco bay is also shallow water but does not have enough fetch for a fully arisen sea to develop. So waves are smaller but steeper. Also San Francisco bay has strong currents (up to 5.5-knots) that can for-shorten waves making them extremely steep. So waves in the bay with 25-30 knot winds against the tide can be 2.5', with less than 3-seconds period (i.e. 1/3 highest wave height = 2.5'). This means highest waves are near 7.5'. These conditions are very uncomfortable for any small boat. But sailing in San Francisco bay we can get lots of practice if we choose to. So there are many bay area sailors who can sail well in high winds and short steep chop. You may not want to do this but I thought you should know that boats can handle these kinds of conditions when the sailors are experienced with them.
Long ago I read a report of life lost at sea in the Gulf. The boat was a J30 sailing down wind under main and jib in 20-knot winds that lost crew over the side. Instead of sailing back to recover the lost crew, they dropped the sails and started the engine but were slow making way against the conditions. Eventually they fouled the prop with a line and the man overboard died. This is a very sad story. However, anyone who has sailed a J-30 knows that it can sail upwind in 20-knot winds by flogging the main a little. Even my children could have done it. People who don't practice in windy conditions do not realize how capable boats can be. When it gets windy, I encourage everyone to reef deeply and then hand the helm to the least experienced crew member. Then play with the baot a little bit, see what you can make it do.
David
On Friday, June 25, 2021, 6:48:34 PM PDT, David Thatcher <david.thatcher@...> wrote:
Hello Michael, ? In response to your question about building the 480 catamaran. As someone who has recently completed an Eco 6 and done some sailing on it can I put forward some thoughts. Firstly your described 25 knot winds and 3 foot seas are going to be a challenge to any of these small catamarans, and the smaller the boat the more difficult those conditions are going to be. I think my Eco 6 would be challenged in those conditions, it would not be pleasant at all. Remember also that the bigger the boat the more stable it is going to be, so for the conditions you have described the Eco 6 is going to be a much better boat. If you are going to go small the new Eco 520 design would be a better option. Similar simple construction to the 480, but a bit more boat with an easy to construct rig, and very easy to reduce sail because both sails are roller furling. ? To get accommodation with a decent double berth, and a toilet area you would need to go bigger, either the Eco 5.5 or the Eco 6,and ?maybe the 520. We find the accommodation in the Eco 6 to be quite workable for two people. I have been onboard a 480 and the interior is quite tiny. Rather than a chemical toilet in our boat I have built a lightweight composting toilet which works very well, and even has my wife’s stamp of approval! ? Outboard motor size – the 480 would suit a 4hp motor. We have a 6hp Honda motor on our Eco 6 and it is plenty big enough for the boat, I have never had to use full throttle even in very windy conditions. But going back to your described wind and sea conditions, any of these small boats are going to struggle under power in those conditions. In fact regardless of the size of motor it might be very difficult to make any headway into those sea conditions as the boat will be pitching so much that the propellor will often be out of the water. A longer hull length will be better in rough seas. ? So for the conditions you have described, the bigger the boat the better it will be, but I really do think the 480 would be too small. This does need to be factored against the extra build time and cost of a bigger boat. The Eco 6 was 2 years committed part time work, and about NZ$15k. You could spend less than that by using second hand fittings and motor, or you could also very easily spend a lot more. I made a lot of my fittings and constructed my own rig, but I have had a lot of sailing and boatbuilding experience. ? Good luck with your project. ? David
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Hi Jack
?
I know that you are living in the Netherlands. I am also Dutch (passport). We could write in Dutch, but here in the group, let's stay in English.
I understand your attitude. As long as you have your job, it is okay.
I had a big smile on my face as I was reading your reply. This is the way it is going with building a boat. You are, anyway, very creative with what you are doing. A vital point is building your boat to your requirements. But regarding the time you need, curse. As long as you enjoy what you are doing, anything is fine. I am wondering? you will transfer the heat absorbent by the Aluminium sheets to the cooling hoses. I would try air cooling. Turning such a big and floppy piece will not be easy. Success. How fare are you now with the inside of the boat? In your last photos, you were already far. Have you made your mind up concerning the E-drive(s)??
Yes, I think it was and is the best attitude to come through this Covid thing.
Have a nice weekend
?
Bernd
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Hi Bernd,
To answer your questions:
I'm living in the Netherlands, and there is compensation available, and I could have used it, but the fact that this is my "professional" hobby business, it didn't feel right and fair to ask for it.
Beside this sound business I've also a full 40 hour job as automation engineer, so we still can eat.
About the catamaran: this week I've laminated the foam on the under side of the bridgedeck to the hulls, which was the last laminating job on the outside of the boat.
And I also started fairing and sanding the outside.
I made a misstake by ordering the material for the (solar) roof which takes a lot of times to correct. I ordered 15 mm thick corecell to save weight, while I need at least 20 mm thick foam because of the height of the wire connection boxes on the bottom side of the solar panels. I recognized this mistake after I laminated the full bottom side, and coated it with epoxy/microballoons and sanded this.
To get enough material at the places where the connection boxes are located, I've added an extra layer of 10 mm corecell ( left overs from a previous project ), made fillets around them, and laminated them also.
When I was looking at the result, I started thinking about a sound system, and that it might be a good idea to install small full range speakers at the front and the rear of this roof. I found very nice Visaton marine speakers, but these need also some extra thickness..... So I made from corecell left overs little cabinets, added fillets,laminated them and now the whole underside of the roof is nearly finished to add the first layer of DD coat.
When the bottom side ( which is the top side now ) is coated for the first time, I'll turn the roof which is 5.20 mtr. long by 3.10 mtr., and will make all the grooves for the wiring of the speakers, camera, lightning and water cooling hoses. This all will be covered by 1,5 mm thick aluminium plates to transfer the heat.
So it's a lot of work for a simple thing as a roof... But I'm sure that I will be glad with all the futures it gets, and make the work very gratefull.
Actually, the whole building of this project pulled me easily through the lock down and other limitations because of the Covid 19!
Regards, Jack
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Re: A few questions about the minicruiser 480.
Hello Mike
Making the right choice is never easy, but when You sail the Gulf of Mexico. You want some adequate accommodation, so your wife will be happy to sail with you.
Many ECO’s are used for longer journeys, for instance, on the Pacific North-West, sailing up till Juno. Not the easiest waters to sail. You do not build every day a new boat.
Also, with respect o stability.
I advise you to build the ECO 5.5.
The DUO 480 is, in any case, too small. It is a day-sailor with a cuddy. A Croatian client had enlarged the boat to 5,2m. He was/is very happy with it. The boat was also used for extended holidays. You can see photos from the family sailing the Mediterranean Sea here in the photo folder. On a typical summer day, we have here mostly less wind in the morning. On the coast, you get almost every day wind till force 6. The waves then accordingly between 4 to 6 ft high. Typical Med seas are (notable on the coast) very short compared to the long waves found on the Pacific or Atlantic. The boat handled these waves very well.
I have drawings for a sloop rig for the DUO 480. Here again, the ECO 5.5 is better suitable for what you need. You can, for example, use a Hobie 14 rig. However, many catamaran sailors step over to more modern boats, and the rigs are reasonably cheap to find. Another good and cost-effective rig David has built for his ECO 6. A gaff rig is more or less a Fathead rig but not so expensive.
Material costs. You need about 35% more material for the ECO 5.5 compared to the DUO 480. The overall difference is not this big.
Construction time. You will need about 50 % more time.
Time is the most difficult to compare. Everybody has a different work speed. How fast you can build also depends, to a significant part which tools you have. The time I show is the time I would need. But I am a very concentrated and organized builder. Here is a saying from a German wood recumbent trike builder.
DON’T MEASURE YOUR PROGRESS USING SOMEONE'S OTHER RULES
Beam restrictions for road transport in your country. Every county has different rules.
But I know from customers that you can get permanent permission till 11 feet for about $ 25,-
David also gives good advice, but he is used to big ships and boats ;-))
Cheers
Bernd
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Re: A few questions about the minicruiser 480.
Hello Michael, ? In response to your question about building the 480 catamaran. As someone who has recently completed an Eco 6 and done some sailing on it can I put forward some thoughts. Firstly your described 25 knot winds and 3 foot seas are going to be a challenge to any of these small catamarans, and the smaller the boat the more difficult those conditions are going to be. I think my Eco 6 would be challenged in those conditions, it would not be pleasant at all. Remember also that the bigger the boat the more stable it is going to be, so for the conditions you have described the Eco 6 is going to be a much better boat. If you are going to go small the new Eco 520 design would be a better option. Similar simple construction to the 480, but a bit more boat with an easy to construct rig, and very easy to reduce sail because both sails are roller furling. ? To get accommodation with a decent double berth, and a toilet area you would need to go bigger, either the Eco 5.5 or the Eco 6,and ?maybe the 520. We find the accommodation in the Eco 6 to be quite workable for two people. I have been onboard a 480 and the interior is quite tiny. Rather than a chemical toilet in our boat I have built a lightweight composting toilet which works very well, and even has my wife’s stamp of approval! ? Outboard motor size – the 480 would suit a 4hp motor. We have a 6hp Honda motor on our Eco 6 and it is plenty big enough for the boat, I have never had to use full throttle even in very windy conditions. But going back to your described wind and sea conditions, any of these small boats are going to struggle under power in those conditions. In fact regardless of the size of motor it might be very difficult to make any headway into those sea conditions as the boat will be pitching so much that the propellor will often be out of the water. A longer hull length will be better in rough seas. ? So for the conditions you have described, the bigger the boat the better it will be, but I really do think the 480 would be too small. This does need to be factored against the extra build time and cost of a bigger boat. The Eco 6 was 2 years committed part time work, and about NZ$15k. You could spend less than that by using second hand fittings and motor, or you could also very easily spend a lot more. I made a lot of my fittings and constructed my own rig, but I have had a lot of sailing and boatbuilding experience. ? Good luck with your project. ? David
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Nightline
Bernd Kohler
bryanandmarycox