Those rollers look perfect for what I need Rael, thanks :)  here they sell heavy plastic caps for pvc pipe, I might go that route and use them for storage as well, work well for my speargun, pole spears and fishing rod.

I'd rather be sailing a small boat than sanding a big one :D

I don't think multihulls require the kind of support that monos do though, all that ballast has to put a fair amount of stress on the structure, most multihull builds seem to use light plywood frames wherever possible.

I do think that I'll design my next boat to be easy to dry out and it'll have a wood stove which helps a lot.

I've read that western red cedar can be acidic enough to keep epoxy from curing and needs to be washed with solvents to remove the oils so the epoxy can penetrate. 

I think if I do strip plank, and I'm leaning that way, I'll use exterior plywood for strips, that way I can fill any voids I run across in the ply. I can get decent 9 mm ext spruce/pine ply for about $30 a sheet, probably about what I'd pay for cedar with much less prep work and a much more durable result.

As much as I like west systems I think I'm going to change brands, maybe Maas or Raka, West is just too pricey, wouldn't recommend anything else to a beginner though.

Bill

Back in about 1980, the first boat I built with the new-fangled WEST resin was a rowing dory, using cheap exterior grade ply of unknown species. Ten years later, the topsides forward consisted of two thin skins of resin and paint, and an air gap in between where the plywood used to be. You had to be careful where you poked your finger.

Tystie was built from good Israeli Gaboon/Okoume ply, well glassed. A piece of non-structural ply, that didn't get coated on one side, rotted out, but the main hull and deck are still fine, I believe. She has Southern Yellow Pine chines and stringers. Where the water got in, in a few places, the wood would swell and split the resin coating. This happened in the first few years, and I opened up the splits and packed them with resin. Not too troublesome after that, but I think the new owner has had to see to some rot in the pine. I don't think I'd use softwood for framing again, for a cruising boat.

And again, on the need for durable timber in a seagoing boat, I heard of a strip-planked Western Red Cedar boat, resin coated, that rotted out in eight years, so badly that the hull was scrapped and only the furniture could be saved. 

they figure that an impact can cause tiny cracks that are easy to miss letting water into the wood, after googling about it for a bit I'm fairly sure it's unusual and at least sometimes the result of substandard materials or craftsmanship.

lol, I'm building a boat with two identical halves, both of which will be the bow or stern about half of the time, unfortunately the bilges and flotation already have 5 coats of exterior latex on them or I'd test both theories, still not too late to encapsulate as much as I can on one end and just do bottom to the water line on the other.

 While I'm at it I'm going to use fumed silica in all but the first bottom coat on one end to see how much abrasion resistance it gives.

Thanks for the wood database link, that's going to come in handy. The luan here is gorgeous, a bad sheet has two or three knots  9mm or less, wish I was a bit better craftsman, it'd look amazing finished bright.

Rael, I wish I had your shop, your boat, and your access to reasonably priced plywood :) 

The beaches here are mostly shingle so I'll probably cary three oars and use them as beach rollers, I'm putting oak runners down the middle on both ends of the main hull, they should take the brunt of the punishment.


Bill

Hi all, 

David Thatcher, Yea, that's the bottom line..... The best way to put it is, wood boats don't like drying out.... and plywood boats don't like getting wet..... As strange as it sounds it's true!

Annie is right, so is Bill..... I guess there's many ways to skin a cat! Do you keep your boat afloat, or high and dry????

Epoxy encapsulation is best if done big time with the most expensive stuff, otherwise maybe better don't do it at all..... Iv'e dove into the subject for many years and have come to believe that it all depends on one thousand circumstances..... There really isn't one correct answer, each case is different.....

My boats are outrigger canoes that I can easily beach, so When ever possible I beach, otherwise I drop the hook. therefor I fiberglass to just above the waterline and go twice on the bottom for beaching. I think it's better that way, since multihulls must be kept light, and I beach a lot, if possible... It's easy, so why not? A day will come when, I may be older, wiser, the boat bigger, heavier..... When that happens we may do things different, for now, I keep epoxy to a minimum.

After glassing, I paint the whole boat with an epoxy 2 pack primer for steel, top class stuff used for painting oil rigs that stay out at sea, on top of that I put a gloss 2 pack acrylic that is recommended as a top coat for that primer, under the waterline. An outdoor mat acrylic (house paint, in America) for above the waterline.

My Big proa, Crystal Clear spent 2 months on a buoy while testing till I finally gave up on her Schooner Crab claw. Still her Poplar hulls, her epoxy are all good. By the way, she's begging for a junk rig..... if I get it right this time, she's next....

Her Maiden sail..... I love her, she just flattens seas.... proas are amazing!!!

https://youtu.be/4yAm2QgKc1c

David Tyler, I buy my ply from Welde, lucky for me they have a big factory close by.

I buy rejects from the reject shed, I flip through the sheets till I find what I like. 

I't not easy, it takes time, but I can walk away with 4x8 sheets of 6 mm stuff at about 10 Euro a sheet. I don't know how much Okoume is, since they don't make it. 

Still I prefer Poplar, it's the strongest, the greenest, the cheapest, and it's everywhere... James Wharram, ( the best cat designer in the world, in many people's opinion...) is building his award winning Amatasi in Poplar Ply....

 Welde's stuff is all well made, the guys in the warehouse said: "our stuff will never delaminate in water!" they weren't kidding.... Glued up with Phenol Formaldehyde, by the book, I boil tested their stuff for a week and nothing came apart! The pieces of ply spent a week in water on the fire place, reaching boiling temperatures several times, by the end of the week, the wood looked like chewing gum! Still it never delaminated!!!!!!

By the way, here's proof that well made poplar ply can take a beating.....

The next vid (a short one, promise... My plywood car....) shows 4 mm poplar, that is now around 4 years old, 3 coats of outdoor acrylic (latex) in front, nothing on the back! Bare ply only! Mud, snow, sun and rain....... still good as new!

https://youtu.be/_Kwx8_whMeI

All d best guys....

 

David Thatcher wrote:

Based on my experience any type of plywood will rot if fresh water gets into it and sits there. So sealing with epoxy is a sensible tactic for any new boat build, or for repairs of older wood/ply boats. Regarding plywood type, it really depends on what is available locally.

And it depends very much on how you seal.  Slapping on one coat of epoxy with a roller, will not protect it against standing water: you need at least three, thick coats or a 'flocoat'.  Well worth reading up the Gougeon Bros on this.  Professional boat builders simply cannot charge out the time necessary to coat the wood properly, which is why too many wood/epoxy boats still suffer from rot problems.  I put at least 5 thick coats on the wood in areas that will never see the light of day again, just in case.

Do they make poplar ply with marine glues?