P/V Luca Széke - my first boat

[magwas]

This is my first full-scale boat. A 6.2m kayak.

All plans copyright CC-BY-SA.

On the pictures you can see steps of the buildings, and my struggle with the end of the boat.

She is not yet fully ready. She now lays upside down waiting for the last layer of epoxy to cure on the bottom. After that she will receive another coat for the top, skirts on the opening, and bulkhead (not for mechanical reasons, just to provide buoyancy chambers.
I plan to upload some pictures of her current state tomorrow.

Her name Luca Széke (Lucy's chair) is a reference to an old hungarian custom of building a chair for 40 days, finished at the nameday of Luca. This is an expression referring to something which gets ready very-very slowly.

[gonzo]

It is hard to tell from the photos. The hull looks like a flat bottom pirogue. Is there a V to it?

[magwas]

Originally Posted by gonzo

It is hard to tell from the photos. The hull looks like a flat bottom pirogue. Is there a V to it?

I don't know what counts as a flat bottom The bottom panels have slightly less than 180 degrees to each other according to the plan, But the actual boat have areas where it is very slightly concave from below.

Here is a picture of her bottom I have just shot, judge it for yourself.

[magwas]

The lesson learned about the ends of the boat:

I did add three thick layers of epoxy to the inside of the boat before adding the top panels, and in the ends I have put copious amount of putty. I did it because I didn't want to paint much inside later when it will be hard to reach.
I did not really care about that it became a bit narrower than designed, thinking that the top panel will push it away. It was more or less true for the middle section, but epoxy made the ends rigid. I have tried lot of things to solve the problem, including cutting small sections of the top out. The most effective was to press the top vertically. The fifth picture shows the ropes and tools doing this.

[magwas]

Here are the promised pictures about the current status.

The first is the whole picture.
The second is about the end. I think it is much nicer than one would think based on the amount of struggle with it.
The third is the model which shows how the skirts will be done soon.

[magwas]

One of the skirts starts forming.
The material for the other one is curing.

It is made of jute. It will be too brittle in itself, so I will use something else for the further layers. I am too impatient to wait for my flax cloth. As this part not severely needs a structural material, most probably I will try a flax-cotton mix which is more easily available.

[magwas]

I have continued with one of the skirts of the boat.
I have cut out the skirt some 2 cm above deck, and exactly below deck.
I have made the upper cut with a dremmel tool flex head. The lower one was quite a fight, at the end a claw (I hope this is the correct name for the tool which is normally used to pull nails out of wood) proved to be the right tool, but maybe just because this jute composite is really too brittle.
I have used a piece of hose pipe to make the form of the flange. I have whipped it around some polyetilene foil.
The greatest lesson was the lamination. Well, one should throrougly prepare for a lamination, and know every detail in advance. I just cut some strip out of a flax-cotton textile, put it to the place, and started to mix epoxy.
Now I know the following things:
- If you want to use more layers of laminae, cut all of them in advance
- Textile (I am talking about natural textile, not glass or carbon) can be most effectively wetted for lamination by forming a roll, and periodically dipping it into epoxy.
- If you are laminating to some core or already cured material, it is a good idea to wet it with a brush.
It was a bad idea to cut out the below deck part of the skirt so early. It would have given more area to stick the cloth to.

My main concern is whether this layer will correctly stick to the skirt. Forst it seemed it won't. Now I think it maybe will. We will see tomorrow.

[magwas]

I did the 2nd run of laminating one hole, and inserted the vertical panel to the 2nd.

The 2nd run was 2 layers. Those layers are well cured to each other, but there are 'delaminations" to the 1st layer. I guess I should have choosen lighter cloth for such a complex shape, and use more layers in one run.

Despite I was careful to lay the clothes to place before lamination, I have tried an inadequate method for wetting them at first. Wet the textile first, and then form a roll, not the other way around. Because of this mishap I have managed to lay the second layer in the wrong direction, so the cuts did not went to their planned locations. Again, maybe a lighter cloth would have given me more leeway.

I was also struggling with cutting it to shape. I am using a dremmel tool - a cheap copy, not the original - with really thin flex discs. I have managed to break 3 discs cutting out what you are seeing in the picture. Also the piece holding the disc became unuseable, so I am using an ordinary bolt and nut, and it works better than the original.

Well, plenty of bad workmanship here I hope these lessons will help someone to avoid the same mistakes.

[magwas]

It is a bit frustrating that as the building advances it becomes more slower.

I cut the first skirt (what is the proper English name for than anyway?) to size. I have solved the problem with breaking cutting disks (yeah, I have realized this might be the word for "flex head") and bad tool head by replacing the tool head with simple nut and bolt, and using two disks. Now it does not break, however I have to be careful not to overdrive the tool.

After cutting the skin I have realized that it might be easier to add one more layer below than grind the inaccessible places, so I did that. There are some places where the cloth have bound nicely, and there are some where it isn't. I hope it is still not a lost case, after all epoxy can cure nearly any problems of life

I have continued with the second skirt, which I think is better so far. I did the lamination of the upper layers in one run, but there will be the struggle with the bottom as well.

[magwas]

I have coated the skirts with flexible epoxy. SR8500+V51+SD8500+wood powder.
There should have been some problem with the mixing, as it was very tacky even after three days. I applied an acetone rug, and put her on top of the car.

She had performed well, at least as far as a first boat goes. Well, she is too short and too high, and have its weak points (e.g. the skirts), but overall I had been very content with my work, and played a lot with the kids in a nearby lake.
As my wife likes canoes better, right after we arrived from the maiden voyage I have made some serious cuts to her (the boat, not the wife).
The deck is almost gone. I will put bulkheads in the ends to make buoyancy chambers, a piece of wood across to give her some transverse stiffness, and wood bars around the hole.
The epoxy is now cures on the first bar.

[magwas]

The boat is ready, and thoroghly stress tested. She performs very well.
I have spent 2 days fouriously cutting and epoxying, because we have planned a short week on Lake Balaton. Due to the time constraint not everything is as nice as it should be, and most of the seats have only one layer of epoxy. But she had been ready at time.

At the lake she had endured some serious abuse. She was able to freight the whole family (two adults and three kids) despite that she had been originally designed as a two person craft. The favourite game of my three kids has been turning over the boat, filing it with water, sitting in and paddling. The buoyancy chambers got some water, I think mostly because the closing panel was fitted to tightly to have some glue between it and the rest of the boat, and one layer of epoxy wasn't enough for both the mechanical stress and waterproofing. I consider fixing this and adding one or two more layers as a maintenance task, because I have already bought the material for my next boat

I have received some wholehearted compliments from strangers, so it seems I could design and build a not too ugly boat after all. Though it was obvious to everyone that she is home-made.

I will post photos as soon I've made some.

[magwas]

Here are the photos I have promised. I don't know whether anyone reads this thread though

[Petros]

that looks like a good adaptation for your hull. It appeared too wide to be a suitable kayak anyway. Two person kayaks are not as practical as they appear, two small one person kayaks are more useful and about the same amount of effort to build. A large cargo carrying canoe is far better for a family outing, camping and playing with than a 2 person kayak anyway.

Now that you learned on this one, time to start planning a proper kayak for yourself.