More plywood discussions

I guess the real question is: "Are you building a boat you can be proud of?"

Exterior grade is significantly weaker than marine grade, if both are built to specs. Any voids will greatly weaken a sheet of ply.

The exterior ply I have seen lately was bad enough to make my stomach turn. It might be ok for roof decking, but I would not want to use anything with bondo from the start ....

My 2 cents. YMMV.

Wayne

 

The real question is why on earth you would try to save ~2% of the total build cost on such a key structural item ?

You are hanging expensive Epoxy, FG, and especially paint - along with all the machinery off this 'base' component.

Say Marine Ply was ... $80, and construction Ply was ... say $50, thats sounds like a great saving. For a 26 footer, thats $30 by 20 sheets - a whole $600.

Say the whole boat will cost $15,000 - all that extra material is hanging off a potentially under-performing structure, and all your hard work has been spent on a potentially short-life craft.

 

Construction grade CDX plywood is only about $12 a sheet, not $50. He is not talking about a $15K boat here, but only $3-400 I would guess. The savings is significant, like half the cost of the build. But worth it only if you do not mind the extra weight and know it will not last as long as using more costly marine plywood.

 

Point taken, its only a small boat as you say.

Weight is a good point - its amazing how much more use you get out of the lighter boats, its much easier to launch, retrieve and store, so you tend to use it more.

With regard to costs though, the same logic does scale down.

Lets say he buys 4 sheets of marine ply $200, versus 4 sheets of construction ply $50.

Paint is going to cost at least $80 to $100, epoxy and fg will cost around $150.

So we are talking build costs between $450 for quality ply, to $300. Thats $150 saving for a boat you will spend ... say 100 hours to build.

With that much personal time invested, the feeling that you have a problem free craft for the sake of half a days work is hard to argue against.

As many boats spend a lot of time just hanging around aging, the life of a boat is dramatically dependent by the quality of the basic materials. The ability to leave a boat out in the weather instead of expensive storage is a great asset, but one you have to forgo if your construction is a bit 'iffiy'

 

I thought the marine ply was $80. that would make $360 for plywood, and total cost of $600 vs $300. and if you for go the fg and marine paint and use house paint, total cost would be closer to $75, but would last about 4-5 years.

Since it is a first time build, you will likely not get everything the way you want it, and after a few seasons of use you decided to build a better one. than you have not wasted $600 on good materials on a design you found out you did not care for, and where your building skills were not very experienced. So once you have some time building, and time in the boat, you can than build your sencond one using the better materials, that you will have longer and enjoy much more.

After you build one, you just can not stop. So using low cost materials for your first "test build" can still give you a useable boat with much less investment. It allows you to build skills and time on the water. Once your new "good" boat is built, you can give the first one a fitting "viking" send off and not feel you invested too much money into it.

 

I honestly would not want to use construction plywood to build a house. I have watched corners chip off while being laid in place on construction sites ....

Cheap is cheap and you only get what you pay for.

If you are just trying to save money and learn the craft, then build a model. Or, help someone build their product right.

But, if you practice cutting corners, when do you switch to quality?

IMHO.

 

yeah, there are two schools of thought about the approach.

Personally, I build everything like I will own it forever, and even if I dont end up keeping I wont be haunted by the new owners drowning from bad construction. I also wont have to burn it or pay tip fees.

There is very little benefit from doing something halfway - my time and trouble is worth more than that.

 

I have personally seen not just one but two searunner 31 trimarans that were cut up with a chainsaw and hauled to the landfill because of using substandard materials, one was amature built with poor workmanship to boot but the other was profesionally built but built with poor materials, i also met a guy who had built and extensivly sailed a constant camber tri which was so poorly built that he couldnt find a buyer when it was only a few years old so he cut it up and saved the rig and used it for his next boat which he built to one of Richard Woods designs, it was also very rough but again he cruised far with it. I just dont understand using garbage materials and if you have no skill,just buy a boat.

Steve.

 

Flatsbuilder,
as others have said, it's pointless saving a few bucks to build a piece of crap, pay for decent materials and be proud of your work or just go buy a used boat.
You won't find justification for being a cheapskate here.
RR

 

The last plywood boat I built had a $1,400 plywood bill, all BS-1088 or BS-6566 grade (the good stuff). Total materials for the build of this 16' boat was just over $7,000, not including labor and including substantial professional builder discounts from vendors. This works out to be 20% of the cost of the stuff involved in the build, again not counting labor. Maybe you can save a few hundred bucks off the $1,400 plywood bill, but is this where you really want to save money? I used LPU paint, at hundreds per gallon and could have save considerably, if I used a single part polyurethane or standard alkyds. I used 316 fasteners and could have lived with 304 for an additional savings. I used mahogany and teak trim, which could have been pine and oak for more savings. The list goes on, but there are lots of places you can save money in a build, without compromising on the very stuff that keeps your socks dry.

 

A lot of good advise from the pros. I'm more of an amateur, but I've gained some first hand experience working with different materials over the years.

As I restored a small cruiser I've used three types of ply. Okoume, Douglas Fir, and an inexpensive interior/exterior grade called Aruacoply. I see Okoume at $135.00, Douglas Fir @ about $70.00 for 1/2" sheets. The Araucoply is an interior/exterior grade ply that I used for interior cabinetry and for some very well encapsulated work on the flybridge. I would NOT recommend Araucoply in a load bearing application or below the waterline.

Once you actually get Okoume and Douglas Fir in your hands you'll understand why one costs double the other. I used the Okoume for some load bearing exterior bulkheads and for the cabin roof. Douglas Fir was used for the boat's decks.

The first thing I noticed was the finish on the panels. The Okoume is beautifully smooth. It absorbs epoxy nicely, evenly. Once sealed with three coats of resin I sheathed the panels with a thin layer of fiberglass cloth. It broke my heart that I had to paint the cabin top. That Okoume looked a lot like the top of a grand piano.. It had to be done though for UV protection.

The Douglas Fir has a wild grainy look to it. It absorbs resin unevenly and I had to do some extra sanding to get it close to looking good. As a deck material it's OK, perfectly serviceable but not nearly as good looking as the Okoume. If I could do it again, I would skip the Douglas Fir. I'm not an engineer, but after spending many hours working with both materials I believe that the Okoume is stronger, even though it is lighter.

If you can find a way, my advise is to use the good stuff. Maybe you could put in a little overtime or get a temp job for a few weeks if money is tight. Good luck on your project and have a happy new year!

 

Boatbuilding...or anything to do with boats, is supposed to be a pleasure.

Working with top quality materials is a pleasure. If youre a bit short of cash for top quality..............STOP !!!!!!!!!!!!!!!!!!!!!!!... go make some more money, then pursue pleasure.

The same goes for professional design fees, tools, fit out.

Dont do it unless you can do it right

 

I couldnt agree more, ive built several large boats for guys who understood this and were willing to put the brakes on and generate more money to continue rather than compromise quality, customers like that are rare, a pleasure to work with and very much appreciated, i have yet to encounter one in the US.

Steve.

 

Although I generally fall in with the use-the-best-materials-you-can crowd, I think we need to keep a sense of proportion -- specially on small craft. Sometimes 'tis better to put something together out of what's handy or what you have the money for and get it in the water, than to wait until you can afford the very best.

One of my canoes was knocked together with scraps from a jobsite dumpster, and it lasted me (and later my children) for years. As a matter of fact, we probably got more hours of fun out of it than we have out of any other boat I've ever owned....

 

There should be noted a distinction between what a professional can accept and what a back yard builder will incorporate, into their build. A back yard builder often does so out of ignorance, while the pro has been burned enough to insist on something else. Again, as far as savings is concerned, there's lots of places you can cut corners and save money, but the typically, a hull's planking isn't the wisest place to do this, for obvious reasons, which the pros generally accept.

I have several designs that use nearly all materials from big box stores. They're heavier then they need to be, to compensate for the weaker, cheaper stock, but the design can tolerate this and in some cases it's welcome, as it's added heft makes them more comfortable underway. There aren't many designs available for this specific way of building, though some suggest they are.