Fibreglassing a marine ply hull - costs

Par - it just looks like it has shape because of the reflection - look again.
Cowobyisking, in Texas, one can purchase Joubert okume plywood which, IMO is the best for most purposes. Okume, itself, is not that rot resistant, but this stuff has a fungicide that makes it wonderful. Marine plywood, however does not exist as we came to know it, which is doug fir plywood made in one Simpson Timber plant in Oregon. There are other plys that are suitable for some projects just steer clear of anyone trying to sell you exterior grade ply ("It's just as good", "The glue is what matters", etc.).

Frome the Glen-L site;
Marine-grade plywood is made entirely of Douglas-fir or Western Larch. The grade of all plies of veneer is B or better. B-grade veneer may have knots but no knotholes. A-grade veneer has no knots or knotholes. Both A and B grade may contain wood or synthetic patches. Panels are sanded on both faces or Medium Density Overlay (MDO) or High Density Overlay (HDO). The maximum core-gap size permitted is 1/8 inch. Its exposure durability rating is EXTERIOR and the glue used is a fully waterproof structural adhesive. It is considered a "premium" panel grade for use in situations where these characteristics are required. It is available in 4x8-foot sheets of 1/4, 3/8, 1/2, 5/8 and 3/4-inch thickness. Sheets up to 5x12-feet are also available. Available grades are A-A, A-B, B-B (face-back), MDO and HDO.

Marine-grade plywood is not treated with any chemicals to enhance its resistance to decay. If decay is a concern, it should be pressure-preservative treated to an appropriate standard.

The detailed description of veneer grades and Marine-grade plywood is contained in Voluntary Product Standard PS 1-95 Construction And Industrial Plywood.

Sample Specification For Marine Grade

APA 3/8" B-B Marine Grade 4x8 10 pieces

Other Exterior Plywood Grades

Plywood panels rated as EXTERIOR but not Marine, such as A-B, A-A or C-C EXTERIOR, may contain any other permissible species and contain C-grade veneer. Unless specially improved, C-grade veneer is permitted to contain knots and knotholes up to approximately 1-1/2 inches across, and the inner plies may have core gaps up to 1-inch wide.

Exterior glue probably cannot withstand submersion. Gaps, filled knots are a bad thing.
Also, note that it says voluntary product standard. It is the same with BS1088, as well. One needs to trust who they are dealing with. If your local search fails, try Boulter, http://www.boulterplywood.com/

[SamSam]

Finding another boat is a good idea as there are a lot of them available dirt cheap, especially considering you are not planning to move it around.

Commuter Boat's post #12 is the one you would be doing best to follow if you go ahead with the boat in your original post. Here is a thread similar to the same situation as yours, post #13 is mine and describes the process a little.
Advice on hull restoration
In the book, and Vaitses is talking about boats that are actual commercial working boats or pleasure boats that are actually used a bunch, he says that a chemical bond between the wood and frp (polyester resin) is not required, the mechanical bond of the staples is enough. He describes that on some boats, as the wood drys out, being no longer in touch with the water, the boats end up weighing less and actually floating higher, the extra weight of the frp being less than the water that evaporates from the wood.

I don't even want to get into it but sheathing this thing with stapled fabric in poly, troweled 5200, etc., is counter to everything I know (When troweling 5200, make sure to let someone know to come check - you could end up a permanent fixture somewhere).
Notice the cribbing under that boat. To my eyes, it looks like a piece of plywood on end is keeping that thing upright...

[SamSam]

That fin does look like a weak link.

We stayed on Homer spit one night in '95 or so, in the furthermost motel on the end in the furthermost room in the motel. Nice.

I took a series of photos to get a panoramic picture of the marina, where there were what seemed like hundreds of small boats lined up on the first docks. I don't think any two were alike, I was amazed by that and everything else in Alaska.

[kitkats]

I'm not sure about how the keelband is constructed but the chap did say the bilge keels were inch thick solid steel plate..!! I thought that sounded strange but I'm no expert.

[hoytedow]

Cowobyisking,
Specialty lumberyards located in coastal cities like Galveston, Port Arthur or Corpus Christy should have what you are looking for. Specify AA for hull or AB for superstructure/decking and expect to pay more for the superior quality over normal exterior grade plywood. Copper napthanate wood preservative is something you should research also.

[cowobyisking]

Okay so what you are saying is that I could more then likely just go to a boat repair shop and buy the plywood from there, which would probably be easier then ordering it online. Can copper napthanate be used in conjunction with glass.

[Ike]

PAR and I have differed in the past on this fiberglass over old wood idea for extending the life of a wood hull. My take is that it would be better in the long run to fix it properly rather than try to save money by glassing it and then waiting for the almost inevitable rot to set in.

However, if you are going to glass it, do it right as many have suggested above. Use a good epoxy resin and make sure the glass is well bonded to the wood.

Wood does expand and contact even when coated on one side with fbg. just the moisture in the air will cause expansion and contraction. Wood is aliving thing, and to completely stop the exspansion contraction you have to completely seal the wood inside and out such as in the WEST approach.

Also, vitually all boats leak, or get water in them. (Even mine, which I have always prided myself on a boat that doesn't leak.)

So, if you don't buy a fiberglass boat, and do buy this one, get it done right. Spend a little extra up front and it will pay you back in the long run.

[hoytedow]

I did not purchase my plywood from a boat repair shop. I purchased it from a lumber yard in Tampa that does business with boat repair yards and sells the stuff retail. The boats I built were painted with copper napthenate and allowed to dry before I fiberglassed them. The boats were under 16 feetlong and I had no problem with delamination due to the treatment.

[cowobyisking]

Okay thank you for all the great incite, you all are a lot of help thanks.

[scotch&water]

Hello all you great boat craft folks, we are finishing a wood boat project and coated with Epoxy 2 sheets of boat cloth and paint will be polyurethane. I ran on to a web of Stancraft Boats Post Falls Id. Sid over on the other side of the mountain builds great looking composid wood boats with 5200 must get the stuff in 55gal drums and make 3m smile, check it out. Well its short of 1800Hr and wine time! Fritz