I am with Bernd on this one. If you are building in plywood then use epoxy. Using anything else will be a source of regret later!.
Richard
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Thank you to all that commented. At the end of the day the aim is to get a solid structured boat that will last and also ensure safety under extreme weather conditions. Many have suggested Vinylester just like Mike and Alweereengijp have suggested. It's completely new to me and I've never worked with it. If anyone have share your experience please. So far I think epoxy resin is the way to go especially for structural connections of the boat and considering a boat that will live permanently?in water for upto six months.
Thanks?
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Well, there is a middle way too, called vinylester. This is not prone to delamination nad osmosis and sticking better to wood. Price is in between epoxy and polyester.
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Op 10 dec. 2021, om 01:44 heeft voya12m via < voya12m@...> het volgende geschreven:
Hi Samuel
I have used polyester resin twice before.? It stinks. Fumes are very bad.
It does not bond to wood very well.
It is not as strong as epoxy.
I would pay extra for epoxy.
Patrick
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To start with, again, in the total boat building process, I mean the complete sail ready boat,? including engine, or a sailing rig,
(Excluding Electronic gadgets like on a Christmas tree, which would make the equation even more favorable for Epoxy)
the cost for the Epoxy is only a small part.?
Vynilester was developed, to make swimming pools built with concrete, waterproof. So, it is used to protect a Polyester.
Vinylester is only fractionally cheaper than Epoxy. To get a homogeneous structure, it is not worth not using Epoxy.
Cheers
Bernd
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Instead of using polyester resin, if you're trying to save money from the expense of using epoxy, try vinylester resin. It sticks to wood, where polyester does not very well, and it is much more impervious to water. When the early, polyester resin infused fiberglass boat bottoms started blistering, they were usually repaired with vinylester resin. It is what is typically used on lower cost boats for layup.
Sent from my Verizon, Samsung Galaxy smartphone
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Bernd Kohler <ikarus342000@...> added folder /Epoxy
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Samuel
There is no other way than using Epoxy. Only Epoxy bonds to other materials, like stone, steel, and yes wood.
What we want is a composite of (ply)wood, glass fiber, and Epoxy. Only then you will get a long-lasting boat.?
When you compare the costs of the complete boat, Epoxy is counting for around 5 %
David was mentioning allergies for Epoxy. Today you can buy Epoxy, (by the hardener is the culprit)
which is not toxic.?
Bernd?
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Hi Samuela using marine plywood I don't use polyester resin even in my worst nightmare ....
Only epoxy!
bye
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I think the only reason that someone would want to use polyester resin would be because of sensitivity to epoxy resin, and possible cost savings. I did at one time own an older Searunner trimaran built from plywood and sheathed using polyester resin. The fiberglass sheathing did not seem to adhere that well to the plywood, and I did have water ingress issues. ? The good thing about epoxy is that it provides a whole build of boat adhesive and sealing system. The same resin is used to seal the timber, glue the boat together, and for sheathing the boat with glass cloth. Epoxies such as the WEST brand can be expensive, but there are also good and less expensive non-brand epoxies available. Also the cost of epoxy resin is only a small part of the overall build cost so it is debatable whether going with polyester can really be justified from a cost saving perspective. ? I used the Coppercoat antifouling system on my boat which is based on an acrylic epoxy resin so alternative epoxy resins based on acrylic technology could be worth investigating provided they had the same adhesive and sealing benefits that traditional epoxies have. ? David
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Re: My son loves his trimaran now its my turn!
Good advice Ivan. Amusing but true
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I have read the big problem with poly is delamination.
Hello all,?
Just wondering if any builder here used poly resin for their boat build. If so, why did you choose to use poly resin and what kind of result did you get?
For larger boats poly resin will be cost effective of course but their has been this debate that the water permeability is an issue with poly resin. Thoughts?
Regards
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Re: My son loves his trimaran now its my turn!
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Hello Mike, ? There is nothing wrong with wanting to go to a smaller boat. I have gone from a 10 meter offshore cruising yacht to the little Eco 6 catamaran. If you want to find out what a small catamaran the size of the Duo 480 is capable of then read the book, or do a Google search on ‘Travels with Miss Cindy’. ? The reason I chose the Eco 6 is that I wanted a boat suitable for sailing holidays for my wife and myself so the Eco 6 accommodation suited my needs, plus I wanted a boat capable of handling the boisterous weather conditions we often get in New Zealand. I do not consider the Eco 6 to be a trailer boat. We keep ours on a swing mooring close to my home and in a good sailing location so it suits me to be able to go out to the boat and be sailing within 10 minutes of being on board. ? The Duo 480 would be a good trailerable boat suitable for casual day sailing and possibly even some weekends away, it is a sort of a backpacking boat. I think though that the success of the Duo 480 would rest on being able to find appropriate masts and sails. Brian here in New Zealand seems to have found a good rig solution for his 480. ? The 520 is very similar to the Duo 480 in terms of capability but being just that little bit bigger will have more space and probably stand up to a bit more weather. The way my mind works is that if I was interested in a small catamaran and I was tossing up between the 480 and the 520 I would think that for just a little bit of extra work and extra cost the 520 would give me more boat, so that is what I would go for. When I originally found Bernd’s website I was thinking about the Eco 55, then I saw the Eco 6 and for a boat just half a meter extra in length it provided a lot more boat with a better interior for not a lot of extra relative cost or construction time, so that is what I went for. ? Good luck with making the decision, I imagine you are itching to get on with the project. ? David
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Hi Samuel
I have used polyester resin twice before.?
It stinks. Fumes are very bad.
It does not bond to wood very well.
It is not as strong as epoxy.
I would pay extra for epoxy.
Patrick
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Hello all,?
Just wondering if any builder here used poly resin for their boat build. If so, why did you choose to use poly resin and what kind of result did you get?
For larger boats poly resin will be cost effective of course but their has been this debate that the water permeability is an issue with poly resin. Thoughts?
Regards
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Re: My son loves his trimaran now its my turn!
At the risk of stating the obvious my comment is that any cruising cat should be sailed as follows then the level of stability of different designs doesn't matter:-
1) Beating or reaching - reef when the wake of the windward hull reduces significantly compared to the wake of the leeward hull in the gusts (i.e. the hull is starting to lift). Or when your crew becomes frightened!
2) Running or broad reaching. reef when the ride becomes noticeably wet or your crew becomes very quite or frightened.
3) Any point of sail - reef when you wonder if you should.
4) In rising winds always over reef the main - you can always shake out the reef if speed drops too much and it becomes obvious that you have over reefed.
In general competent designers like Berndt will design the rig and sail area of any of their designs to allow the cat (unless the cat is designed specifically for very light wind areas) to be sailed safely in winds from 15 to 20 knots, thereafter they should be reefed.
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Re: My son loves his trimaran now its my turn!
Hello Mike, ? There is nothing wrong with wanting to go to a smaller boat. I have gone from a 10 meter offshore cruising yacht to the little Eco 6 catamaran. If you want to find out what a small catamaran the size of the Duo 480 is capable of then read the book, or do a Google search on ‘Travels with Miss Cindy’. ? The reason I chose the Eco 6 is that I wanted a boat suitable for sailing holidays for my wife and myself so the Eco 6 accommodation suited my needs, plus I wanted a boat capable of handling the boisterous weather conditions we often get in New Zealand. I do not consider the Eco 6 to be a trailer boat. We keep ours on a swing mooring close to my home and in a good sailing location so it suits me to be able to go out to the boat and be sailing within 10 minutes of being on board. ? The Duo 480 would be a good trailerable boat suitable for casual day sailing and possibly even some weekends away, it is a sort of a backpacking boat. I think though that the success of the Duo 480 would rest on being able to find appropriate masts and sails. Brian here in New Zealand seems to have found a good rig solution for his 480. ? The 520 is very similar to the Duo 480 in terms of capability but being just that little bit bigger will have more space and probably stand up to a bit more weather. The way my mind works is that if I was interested in a small catamaran and I was tossing up between the 480 and the 520 I would think that for just a little bit of extra work and extra cost the 520 would give me more boat, so that is what I would go for. When I originally found Bernd’s website I was thinking about the Eco 55, then I saw the Eco 6 and for a boat just half a meter extra in length it provided a lot more boat with a better interior for not a lot of extra relative cost or construction time, so that is what I went for. ? Good luck with making the decision, I imagine you are itching to get on with the project. ? David
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Re: My son loves his trimaran now its my turn!
About stability: these boats are not like a Hobie 16 to sail on. They are stable, and it has to be pretty windy to even be thinking about crew positioning,? weight etc. As regards the 480, it can be built with? 2.3 metre beam, but I built mine to just under 2.5 metres (2.5 is legal standard towing width in NZ). It is hard to pick between these smaller designs of Bernd's, they all have their advantages. I use my 480 for day sailing only, so it has the small cabin but a cockpit rivalling or exceeding the others. I love the big cockpit. If I wanted a boat like this with better accomodation I would be asking Bernd about doing the 520 with the bi plane rig. That's because the bi plane rig is so manageable and I have got access to everything needed to build one. That would be my personal position.?
Michael you havent said what sort of places you would be sailing (open ocean, harbours, lakes?), or how far you would have to travel if you are going to keep your boat on a trailer, or what sort of launch facilities you would use (large public boat ramp with good parking and rigging area, beach access only, or what. These aspects could be a factor. For example I used to launch at a public boat ramp with floating arm at a local marina which was good, except you had to thread your way through the marina coming and going. Then on returning it could get crowded at the ramp. Once I discovered how easy the 480 is to beach launch I never went back to a marina and sailing is enjoyable with plenty of room to sail right onto the sand at the end of the day (providing I can find? the right beach -GPS is a great invention)
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Re: My son loves his trimaran now its my turn!
Hi Mike
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First, thank you Brian and David for your insights. I appreciate this very much. This is what a forum, group should be about. I as a designer biased of course. I like them all, otherwise, I had not designed them.
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Very short, all boats you are interested in have more or less the same stability characteristic. The sail area should be decreased above 20 knots. I add the ECO 6 stability diagram to see the stability characteristic of this boat.?
As mentioned by Brian. The lower CE of a biplane rig plus the possibility to shorten sail very fast is a big safety factor. It is the quickest way to shorten sails.
?
Masts. The windsurf masts for the DUO 480 are a more European solution. Here in France, we get them now in the Winter from Euro 50,- onwards. I admit it is the minimum solution. Brian's masts are the real good solution. Lucky he lives in New Zealand where carbon tubes can be obtained for good prices. I was surfing in Alibaba. Found 80mm diameter carbon tubes for 35,- $ per 1m. So one mast would cost 227,5 $. The bad thing, the transport costs 135 $ to the USA or Europe are the same. Total is 590,- $.? But overall a reasonable price.?
?
Building your own boat has many advantages. We have here some very interesting solutions. One of them is the gaff rig from David and the Dyneema rigging. By using an Al tube as a mast. Hu, a gaff rig? where is the difference between the popular fat heat sail and a gaff sail There is none. But the costs for the total rig were kept down without sacrificing sail quality.
Weight, having a light multihull is a safety factor.? The defense is a fast accelerating, principal, running away from the wind and reducing in this way the force of a gust. By the way. If this happens, do not luff up, bear away and loosen the main sheet to lessen the rotational effect.
Construction time is a controversial issue. It is individual.? For example, the beautiful ECO 55 as built in New Zealand by Hamish was taking two years. Martin in Nicaragua built his boat in 600 hours including the Gunter rig ( see some clips in this video:? https://www.youtube.com/watch?v=ioKESt3xtUU. In Russia, the boat was built in 3 weeks by three men. See photos (Economy cruiser pictures). Take your pick!
To stay in the size range. Brian mentioned it already. Look at the?
KD 650.
I hope this helps you a bit to make the right decision for you
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Re: My son loves his trimaran now its my turn!
David, I know you can't?choose the boat for me. I have 4 sets of plans from Bernd (Tiny Tri (built and given to my grandson) Fun boat., Eco 6, 520 and 480.) I really think I prefer the 480. Did you ever hear of a boat owner wanting a smaller boat?? Thanks for your response. Mike Quincy, Fl
Hello Mike, ? I would have thought that the more beam, and heavier the boat, the less resistant to capsize it would be. But in the case of the 480 this is countered by the fact that the boat has a bi-plane rig and therefore the sails are much lower down so therefore less capsize moment. But I think that all three boats would be stable enough so your choice should really center around the boat that best suits your needs in terms of space and accommodation, and also ease of building. ? In the almost year of sailing my Eco 6 in a range of conditions I have never felt there was a risk of capsize. The boat does heel a bit with the windward partially lifting out of the water, but I am probably more fearful of breaking something than I am of capsize. ? David
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Re: My son loves his trimaran now its my turn!
I am glad you responded and you have the 480. I have been researching windsurfer masts and have found none tall enough to match the boat's specks. I have found tall enough carbon fiber and aluminum flag poles of the correct diameter (approx) They come in sections and I don't?know if they would be suitable?if epoxied together.. Maybe insert a wooden piece the length of the mast to stiffen it up. I think the 480?would be the best for me even though it is smaller than the 520..Based on my 23 foot mono hull's useage I probably would use it more. The reason for the capsize question is my wife would not sail on my 23 because it healed too much.
I have considered scaling the 520 rig and using that rig. But not being a structural?engineer?I don't?know if would work. Again thanks for your information.
Mike Quincy, Fl
On Mon, Dec 6, 2021 at 11:05 AM bryanandmarycox < bm.cox@...> wrote: Hi Michael
the answers to your questions will not, in my opinion, give you a good indication of which will be the best boat for your individual requirements. I will give my opinion on the questions you asked first. Bear in mind I have got the 480 and while I will give you accurate information about that boat only I am not saying it is the best for you
OK, your questions: Stable: the 480 with its low centre of gravity because of the biplane rig. Also if it is rigged like mine the sails can be furled or reefed in a few seconds without letting go of the helm.
Faster: in theory of course the boat with the greatest waterline length should be the fastest. But if the boat is loaded up with cruising equipment and is fitted out with a toilet and galley (kitchen) and there are 3 or 4 people on board, then the biggest boat may not be the fastest. For example if you are doing day sailing and carry only the supplies needed for the day, and if there are only 2 people on board then that boat, whichever model, will possibly be faster. Multihulls get a lot slower when they are heavily loaded as Bernd will tell you.
But look, these questions are only part of what you need to decide. You need to decide if you are going to do extended sailing including summer holidays, not just overnight. If you have got access to a nice place to put the boat on a mooring like David has with his Eco 6, then you can avoid owning a trailer and the associated costs. If you are going to keep the boat on a trailer and launch it every time you sail you would be at an advantage if you dont have to travel too far to launch the boat.
If you are going to launch the boat every time you sail as I do then I guarantee the 480 is far, far quicker to rig. The 520 of course is a new design so we havent seen it yet. But I have been lucky enough to visit David a couple of times when he was building his Eco 6, and also Hamish with his Eco 5.5. They are both beautiful boats and the builders did a great job with them. So I am not reccomending the 480 over these other boats, i really like them all. By the way we also had a KD650 built locally here as well which I sailed on many times and that is a great boat too if you want something a bit bigger.
I hope David may contribute to this discussion and tell you more about the 6. He is also a vey experienced sailor and has published sailing and cruising books so he knows what he is talking about. Any boat with a cabin takes time to build so it also depends on your personal experience. For example David built his 6 quicker than I built the 480.?
regards
Bryan
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Bernd Kohler
bryanandmarycox