Thread: Goat Island Skiff (Chile) - Construyendo un pequeño bote de madera en Chile

1) After a long time, I found a wooden boat builder in Santiago. This guy works mainly building "Pirats". He has no website, he works in the back of his house in a small workshop. I don't think he has much workload. He had one Pirata almost ready... I'm very tempted to buy it. This guys doesn't use epoxy, only phenolic glue or something like that, which is cheaper and easire to get. My impression was that phenolic was ok for gluing but it doesn't seem to have any structural properties. He does use screws. I asked him to build the spars for us, we had a lot of trouble getting the right wood and this guy knew all the local trees and has a lot of experience. He told us there is no 6mm marine plywood available and if you want it you can order 100 plys (about AUS$50 each), I think unless I open a boat house is not worthy. We had a nice talk about wood boats too. Next time I visit him I will take some photos.

2) I got the epoxy resination resin, 2 gal (9kg) I hope it should be enough. According to the specifications it does have UV filters, but my plan is to varnish all the inner surface and to paint it from outside (dark blue). I was thinking to leave the gunwale without capping just as it is. It is mainly beacuse the oregon grain looks wonderfull ?Will it cause any trouble in the shape of the hull. I think the 9mm ply is stiffer than the 6mm and it should be fine, but i will be happy to hear comments.

3) We have order the mainsail. We decided to use a balance lug with some modifitacions. We found an old laser mast. I want to weld both parts and cut it to lenght (4730) as if it were wood. We are discussing if we should get the yard and boom from duraluminium or wood, but I whit we should use duraluminium. There is still time to go.

Saludos,

JC.

Originally Posted by Juan Carlos

1) After a long time, I found a wooden boat builder in Santiago. This guy works mainly building "Pirats".

I asked him to build the spars for us, we had a lot of trouble getting the right wood and this guy knew all the local trees and has a lot of experience. He told us there is no 6mm marine plywood available and if you want it you can order 100 plys (about AUS$50 each), I think unless I open a boat house is not worthy. We had a nice talk about wood boats too. Next time I visit him I will take some photos.

The phenolic glues are good but you need tight fits and high clamping pressure. So the epoxy is quite trouble free in comparison and more forgiving for amateur (and often professional) building. Some parts are easier to organise good clamping and tight fits .. like laminating solid spars. There are a whole range of other glues that are also good aliphatic, urea formaldehyde, polyurethane moisture curing. But epoxy is the only truly forgiving one that will fill gaps structurally.

2) I got the epoxy resination resin, 2 gal (9kg) I hope it should be enough. According to the specifications it does have UV filters, but my plan is to varnish all the inner surface and to paint it from outside (dark blue). I was thinking to leave the gunwale without capping just as it is. It is mainly beacuse the oregon grain looks wonderfull ?Will it cause any trouble in the shape of the hull. I think the 9mm ply is stiffer than the 6mm and it should be fine, but i will be happy to hear comments.

Without the capping will be OK. But the harder wood will protect the oregon (douglas fir) better as it does tend to split on impact.

3) We have order the mainsail. We decided to use a balance lug with some modifitacions. We found an old laser mast. I want to weld both parts and cut it to lenght (4730) as if it were wood. We are discussing if we should get the yard and boom from duraluminium or wood, but I whit we should use duraluminium. There is still time to go.

Be careful with modifying the rig. This is perhaps one of the most highly developed parts of the boat.

It is hard to weld many aluminiums as they go soft when welded. It would be better to use the standard joiners ... or make them out of glued up plywood.

Best wishes
Michael

Thanks for the comments Mik.

The modification on the rig is only the swap from wood to duraluminium. We found this old laser mast and I think is a good idea to use it. I think from what you said, we better glue it or use a bolt to keep both parts permanently together as we do need to cut it in lenght a little bit.

Which other types of wood should be fine for the yard and boom? There is very hard local wood, but very heavy, call "Paquio", it is like a bone to work with, I'm not sure if it is right.

Otherwise, should it be fine to use aluminium for boom and yard? can we use just a tube of a constant diameter, lets say 2 or 3cm, maybe narrower at the ends?

I have another question regarding the traveler, Is there any reason to use it attached to the arms of BH4? I was thinking it might be better to attach it somewhere closer to the back to have more useful space over the rear flotation tank. It is difficult to have a solid opinion without having sailed the boat... I'm keen to hear your opinion.

Regards,

Juan Carlos.

Juan, Great to see you and your little one! I too have shots of my little guy inside my boats under construction. Fun to see. It will be most fun to get them out and sailing, rowing, etc. I thing the Goat will be a good boat. It is a very, very stable boat. Yet it has a big sail so lets tie in a reef or two when the little ones are aboard! And I will have oars handy (maybe a motor at some point) to get the boat flat if we need to come back sooner than later.

Cheers,
Clint

Oh no ... I wrote a long reply to you Juan Carlos ... but it must have not finished uploading when I logged off (slow internet - also means I cant look at the pics at the moment ).

With the traveller ... just untie one end or use a clip when you are using the boat without the sailing rig. When using the sailing rig all small light boats sail very much better if you keep the weight near the middle seat (having weight in the back is particularly harmful). You can see quite a few pics on the GIS website and through the posts here of the different ways people sit around the middle of the boat.

But with rowing or motoring the traveller can be untied at one end to free up the seat.

It is best to use the wooden yard and boom as they bend the right amount to allow the sail to depower when the wind gets stronger. There was one GIS built with aluminium yard and boom and it did not sail well at all except in lighter winds.

Making spars from wood is one of the most enjoyable parts of boatbuilding for many of us. The method is pretty easy ... but does take a bit of work. To make the spars .. apart from the gluing will take about a half day (or maybe a full day) but you can do that over many days if you like.

Best wishes
Michael

The best way to

Juan, Wood is good for spars. It has great strength for the amount it bends. Bend is good...it helps spill air from the sails in gusts, etc. It also looks really nice. Trust me, making a spar or an oar is a very straightforward procedure and perhaps the most fun of the whole project. I have made a number of spars and oars as has other here. In fact, I gave an spar making workshop for about 6 volunteers for my youth boatbuildnig project. I can try to write that up in a legible format and post it (I do have an oar making procedure already formed...I intend to modify it when I make some oars for the MSD and GIS b/c those are not all from solid wood (ply blades). Anyway, spar making...follow the right procedure and you will get great results and have a lot of fun and gain skills.

Cheers,
Clint

Thanks MIK and Compass,

I think I just got dissapointed with the spars because of the lack of knowledge on local woods. The boatbuilder I visited had beautiful local woods that he choose by himself very carefully, but he didn't want to tell me where exactly does he gets the wood from... (that wasn't very nice). Thewoods I used didn't have the right grain and they were so hard to plane... At last I gave up and decided to ask this guy to make them for me. It is quite hard to build a boat and to be a surgeon... I have to answer the phone and talk to people with the epoxy stuff getting hot in the bin... and look after the little one at the same time!!

Anyway, I gave the first layer of epoxy resin to the flotation tanks and it does look great. I will have to sand before I give the second hand.

It is ok. to use poliuretane varnish on the wood over the epoxy? should I use an epoxy varnish? Which kind of paint do you use for the hull?

Anyway... my plan is to finish the front tank and put the cover, the go to middle seat and by the time I reach the back tank I should have the fittings for the rudder.

Thanks for the support, It is quite difficult to get started in boat building and be "lost in translation"... specially with local suppliers.

Feliz año nuevo

JC.

Juan, I here what you ar saying about time and boatbuilding. It is ironic that I am a boatbuilder by trade and can tackle some "complicated" projects but it is the simple and elegant boats that are beginning to attract me more and more thus the GIS and other flat-bottomed boats. I assume you are hot coating the epoxy, the "wet-on-wet" method in the manual. The key with epoxy is to put the coats on thin and tip them out nice and evenly...it is hard to sand an uneven coat of epoxy. It sounds like there are no issues about how it is going on, so that is good.

Yes, a polyurethane varnish will do very well over epoxy. Just be sure the epoxy is very thoroughly sanded: it should change color to a dull, sanded look all over withouth any shiny spots left over. Sand those out when you see those spots or scuff them up. I like to hot coat, but sand before the last coat of epoxy if things are looking a little rough. Smooths it out and the final coat comes out much better. A final sand on the third coat looks great. A two part varnish will be very tough. The nice thing here is that you can hot-coat this too, you don't have to wait for it to dry then sand then apply another coat. You can add another coat once the previous coat is just about tack free. For the hull, same thing applies for paint: the one part polyurethane paints make a very durable finish, yet a very glossy finish too. If you use it on the interior, add some flattening agent to the paint to get it to be semi-gloss instead of "hurts-your-eyes-when-you-look-at-it" glossy. Keeping it a semi-gloss will also maintain some durability. On the interior, I always flatten out my paints substantially, my preference but I think most find flatt paint looks best inside a boat. The two part paints are very durable and you can hot coat them. Just one word of caution: all these paints have lots of solvents and the sanding dust is nasty stuff so I really be careful with my little guy and make sure none of it gets near him and that if he visits me in my shop things are cleaned up, the floor, surfaces and the air. In fact, he knows he can't come in at all sometimes.

Cheers,
Clint

Howdy Juan Carlos,

Allowing the epoxy to cure between coats does waste a lot of time, but it may be because of all the different things in your family and work life you have to balance.

The epoxy can go on "wet on wet". Which means you do one coat ... wait for the epoxy to go sticky and then put another coat over the top of the first, then wait for that to go sticky and do the third coat. This means everything is finished in one process and eliminates the problems with "amine blush" a waxy residue that sometimes appears when epoxy cures.

Haha .. because of my limited time on the net at the moment I didn't read Clints comments .. he has covered it all very nicely. Thanks Clint

Best Wishes
Michael

No prob Mik. Good point about other things in life going on causing one to miss the epoxy window. This happens frequently to me! Usually it involves a small human, about 3 1/2' tall (not sure what that is in metric right off, sorry).

All the more reason, Juan, to use a blush free epoxy, so if it does cure on you you don't have to wash off the wax that is given off by the curing. Getting away from West System has changed my life in this regard. But I won't give up beer or coffee.

Cheers

Thanks for all your comments guys.

I don't have much experience with epoxy, but I have learned a couple of things:

1) Thin layers is better.
2) It does look like chalk after sanding (thks. Compass, I was very worried the first time).
3) I have just done some sanding before the coats and it seems to be enough. Maybe is the typo of resin I'm using.
4) epoxy resin has a good performance. With a yogurt pot (165ml) I did both tanks form inside.

I'm very keen to see how it looks with the varnish.

I had a talk to the boatbuilder from Santiago and he told me that he uses car paint and mass! it will be easy to find.

I have the front tank almost ready and now I'm working on the mid seat.

Cheers,

JC.

I have a question regarding a GIS called Gruff, the owner has a nice website. Do you know how did he got to do the filleting on top of the buoyancy tanks? it does look very neat. And it is whit in color rather than grey (that's the way my epoxy glue looks).

I saw some pictures of other boatbuilders from Duckworks, but their filleting and finishing doesn't look as neat.

Saludos,

JC.

JC, The best fillet you can do is by mixing in colloidal silica and wood flour. Gruff's fillets may look neat, but the white color I think makes them stand out too much. The wood flour matches the tone of the wood and the fillet blends in. The way you do a good fillet is to mix the wood flour and colloidal silica into the epoxy (try a 50/50 mix) and dump the "blob" into a zip-lock bag, cut the tip of the bag off, and squeeze a ribbon of fillet material into the area like you are a pastry chef laying down a nice looking bead of frosting. Then use a filleting stick (3/4" I believe) and pull it a lonf forming the shape of the fillet. On each side of the concave fillet you get a little ridge that a putty knife will clean right up. Filleting is a skill and may take some tries to get right. The West System manual has a great set of instructions, if I remember correctly.

Sounds like you are learning a lot about putting on the clear epoxy.

Would be happy to help more...
Clint

Also you can prevent mess by either
1/ precoating and sanding the ply sheet faces that will end up on the inside of the boat. If the filleting compound gets on bare timber it will fill the grain of the wood so it changes colour.
or
2/ put some masking tape down each side of the fillet about 6mm away from where the fillet edge will end up. This way any cleaning up mess won't fill the grain in a disorganised way .. so the job willl look a lot neater.

Also slight disagreement with Clint ... tiny really. There are a number of different filleting powders and compounds that work. The ones I would like to add are the proprietary powders put out by the major manufacturers.

The ones in the boat mentioned were done with the Bote Cote filler which is made the right colour to approximately match the gaboon plywood and others in that colour range.

So I would not necessarily restrict myself to colloidal silica.

One way of colouring a fillet is to add a small amount of extremely fine wood dust or to use a microfine iron oxide like the one that BASF sells (originally destined for the surfaces of audio tape) - the normal oxides used for concrete are too coarse.

Um ... this brings out the reason why the colloidal silica works well and goes on smooth. It is because the fibres are very very small. Any powder will need to be fine to work well.

Like I said there are a number of powders that just do not work in terms of strength so check here before going ahead.
Some that do work ... pulverised glass, pulverised cotton, ultra fine wood flour, colloidal silica
Some that do not work ... talc, microballoons, Q-cels.

The microbaloons and Q-cels are excellent for non structural or less structural fillets.

Be very careful about avoiding getting colloidal silica in the air - terrible to breathe it in. Duckflat do all their mixing INSIDE a snap lock plastic bag. They put resin and hardener in the bag and mix VERY VERY thoroughly being careful to get it out of the corners. Then they add the powder ... they know how much powder to how many pumps of resin/hardener so they get it right. Then seal and massage the bag again VERY VERY thoroughly paying particular attention to the corners.

This can be a bit of a tricky process ... but once mastered it reduced the amount of the dust that gets in the air to almost nil.

Best wishes
Michael