hi to all?

i whant know from all of you how you deal with epoxy blush
its ok to flush with warm water and sceen pad but water with wood not see perfect solution for me ( bare wood parts)
i understand that cover sheet with epoxy before save time but 2e bond still ok? blush problem to 2e bond



just receive his morning barils 55gallon of epoxy
58 sheet plywood and lot of fiberglass rolls
so i ?will start soon, k860 or kd1000 ?that is the big question!!
thanks to all

stephane blanchette?
montreal canada ?

The following photos have been uploaded to the DUO 800S Australia album of the [email protected] group.

• 8FCE6A88-3AF6-4559-8FD4-B4F83877C5EE.jpeg
• CBFA659D-69DE-4398-9CCB-BC6B96646D20.jpeg
• 7925DB65-B299-4BB9-9F7F-E6E521320814.jpeg

By: Zee

The following photos have been uploaded to the D.R. Voyager Build album of the [email protected] group.

• 2F46B8C3-610D-4E88-A81B-48D58F59AB6D.jpeg
• C7F04A72-0B22-4759-97EF-4053518A8E6F.jpeg
• DA0F18AB-1BFE-469C-B2A8-AEF6563415DB.jpeg

By: voya12m

All hand cut.....well I used a hand held circular?saw (really useful tool!) and a jigsaw

Hi
Great start. I will be following your build and look forward to the photos. I intent to start building the Eco75 and later KD122 next year.
It looks like you cbc cut the frames and bulkhead,May I ask where you cut them in the uk?

Regards

Thanks for the link. Your build quality is really nice and you have done a lovely job of laminating the handrails. I note that you did not laminate the bows, but made them per the plans. I have laminated up curved yacht tillers in the past (not difficult) so I think I will have a go at laminating the bows in ply with a softer wood "bump strip" on the outside.

Richard

Hi to all

?

Very nice to see all the activities going on here in the group. Thanks for every photo. Besides showing the progress from a boat under construction, it will help others to start their project. As important as that, many times you see new solutions.

Okay, the go sometimes not in the desired directions. Many builders still think more structure is better. A bit more material here and there.

?

A statement from me as a designer. All my boats are over-designed. For instance, stringers could be 35 % smaller. Besides the quality of the wood is very variable. I calculate that the connection/gluing with for instance the planking to the stringer is only 85 %. To less Epoxy glue or too much. The high humidity at the time of gluing, to low temperature. Any extra weight makes the boat not better but an inferior product!

I calculate from the construction water line (CWL) at full weight. Means, boat weight, and 2/3 added for the persons on board (calculated with 75 kg per person and their belongings), (not the engine, to different weights depending on the power) With this base I calculate the stability, speed, distance water surface to bridge deck distance as main factors. So any piece you add in structure. Too much Epoxy. Had too much made? Smear it in a corner? No, enough is enough, more is a wast and extra unnecessary weight.

As an example:

I have seen very strong extra stringers under a bridge deck. Made from heavy wood. Perfectly built, looks great. But the same strength can be reached much simpler and a lot lighter. Example 80?mm gutter half PVC glued provisional to a bridge deck. 4 layers of 300 grams glass, finished by applying the glass cloth covering and done. Weight decrease by about 75 %. The PVC tube? Stays in. Gutter tubes are very thin and light.

There was a very interesting discussion about closed compartments and rot. Craig, I like your articles and insight as a shipwright. Many persons here will learn a lot from you.

?

Again to closed compartments. Typical for my designs, the first meter from my boats are closed. I call the first bulkhead a collision bulkhead like in the old day's big ship constructions. In my first boat, we used Epoxy. Cipa Gaygy in Switzerland called the material and still call it, Araldit. I was the first to use the material as "paint" impregnation of wood. We used it only on the inside. Because in these days Araldit was very expensive (still remember 87 Swiss franks, in today's money about 150 Swiss Franks)/ Now, the boat is still used. Not for sailing anymore but as a powerboat. The boat was built 1976 (see photo in my photo folder) is now 44 years of age, never a problem with rot.

Good another day more from a visual storyteller

?

Bernd

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Hi Richard, I also built an Eco 7.5 too. I used a similar system laminating 7 layers of 6mm plywood for a large D shape on the bow curve. To lighten the bow weight I cut large box holes in the final part installed.?

Good evening to everybody,
I added new Photos of the Duo 900 Italy. The hull is completed I have just to add the fiberglass and then I turn the hull
/g/K-designs-Multihull-Sailboats/album?id=256248

Hi, I am building an ECO75 and was thinking of laminating up the curved bow out of layers of 3mm marine ply rather than constructing it out of pieces 25x35 and 25x20 timber per the plans. It looks to be easier to do this way. Is it a good idea or you foresee problems?

Richard

No idea ! :)
I don't remember where and when I read it.
But I tried few times and it was quite right, but as we sayed with Bernd, for industrial production.

----- Mail original -----
De: "giuseppe.venditti via groups.io" <giuseppe.venditti@...>
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Envoyé: Mercredi 18 Novembre 2020 15:30:18
Objet: Re: [K-Designs-Multihull-Sailboats] KD860 as a Liveaboard and ocean cruising.

Interesting Cyryl, from where the parameters came?

I happened to find an old Austrailian Boat Broker sales page with many ECO 7.5 photos. I have seen some before but not all of them.
David
https://www.boat-brokers.com.au/index.php?act=viewProd&productId=106

On our Voyager we ended up with five separate buoyancy compartments in each hull as we divided the bigger aft one into two. We ran conduits through them in some places. Each of the compartments has at least one hole for an Armstrong compression deck plate. (You just need a hole, no screws, and they seal very well, not like other deck plates). The idea is to use computer fans to pull air through the holes when the boat is not in use for a long time. This should allow the sealed compartments to breathe. I hope to avoid metal fittings through the hulls completely. That might be unrealistic, but with “organic” chainplates, cleats and stanchions, we have a good start.?

Patrick

Hi Cyril. I mean timber structure sealed with epoxy. Usually the timber was laminated to make it more stable. So we used plywood, cold molding, and strip planking for hull skins and laminated wood for stems, frames and so forth. Fiberglass would be used to increase puncture resistance of softwoods. If you follow Bernd's plans, you don't need to worry about when to use glass reinforcement. He will tell you when it is needed in the plans.

Thank you David !

When you write "expoxy-timber", you mean "epoxy impregnated plywood without fiberglass" ?



----- Mail original -----
De: "David Mancebo via groups.io" <mancebodesigns@...>
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Envoyé: Jeudi 26 Novembre 2020 16:45:20
Objet: Re: [K-Designs-Multihull-Sailboats] DUO 900 Question

Thanks for the answer to my question Bernd.

It has been my experience that limber holes are needed for bilge water to drain to the lowest point in each compartment so it can be easily removed.

I worked as a Shipwright building timber monohulls from 1973 to 1981 and have seen the condition of many of them after all these years. The epoxy/timber boats with good ventilation have had the longest life. Some of them look almost new on the inside after 45-years.

One common problem I have seen on the boats with poor ventilation is mildew on the inside surfaces. The boats with good ventilation did not generally have this problem. The main way we installed adequate ventilation was to ensure each compartment had at least two openings (ventilators or hatches) to the outside of the hull. Lockers and cabinets also need at least 2 openings for adequate airflow to the inside of the hull to stop condensation and mildew. When faced with watertight bulkheads, we installed a low inspection port and a deck ventilator or hatch to induce air flow through the compartment. Both the inspection port and the ventilator would normally be closed when underway to provide watertight integrity.

Over the long life of these boats, epoxy slowly absorbed water. I know this because of the slight discoloration of the timber under the epoxy where bilge water was left. By inducing good ventilation, bilge water evaporates and there is minimal absorbtion of water into the epoxy. Dry wood is stronger and less likely to rot.

Here is a real-life example of the situation. One boat I built in 1977 of cold molded Western Redcedar, okoume plywood and Sitka spruce was sweet smelling with zero rot or mildew until it suddenly began having problems after 27-years. Mildew damaged the inside paint and there were a few small areas of rot in 2 deck beams and a small area of plywood decking. All of these problems were in the forward 1/3 of the hull. The problem developed because the owner closed off the forward cowl ventilator and kept the forward hatch closed tight when moored. The two aft ventilators and companionway vent kept the after portion of the boat in good condition. Closing off all ventilation forward caused the problem. After repairs, the owner keeps the ventilation open forward when moored. 16-years later, he has not had any more problems.

Richard, you would be right in an ideal world. My experience is that few "watertight" compartments are truely waterrtight.

I raced International 10 Square Meter canoes and 5o5's for many years. All of them were supposed to have watertight bouyancy tanks. All of them sometimes accumulated water in the buoyancy tanks.

As you pointed out, common problems are from deck leaks. I would add that leaks around fittings and hatches are very common. I always told my customers to plan on re-bedding all the fittings, hatches and so forth every 7 to 10 years as a part of general maintenance. This seemed to prevent most of the leaks. Some fittings that are "bonded" in place per the Gougeon recommendations rarely need re-bedding. So if you have a truely watertight compartment bonding of fittings can help it stay that way. Another help is to provide watertight conduit for wiring that has to pass through the compartment.

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Hi David,

Thank you David for writing detailed about your experience. A lot of stuff to think about.

Gru?, Günter