Which Grade of Plywood Stringers/Sole

[Barramundi NQ]

Researching for the replacement of my stringers and sole, our local Bunnings (sort of Home Depot) has a number of exterior grades of ply.

For the stringers on my 16ft runabout some here have used solid timber rather than ply. What type of timber is recommended for the stringers? Height and width I can work out. Is plywood that is spliced (kerfed?) suitable? There is an abundance of CD and BC ply

For the sole, I'm confident with BC 12mm (1/2") exterior ply.

If there is a specific thread that you can direct me to that would be fine, if not answer away

Cheers

Gidday from OZ!

Kerry

 

[jigngrub]

BCX is fine, CDX will contain large and numerous inner voids.

Plywood is stronger than dimensional lumber.

Laminating plywood stringers with lap joints is fine if you have a good enough lap. I like a 4' lap.

Deck plywood thickness should be determined by:
1. What will be supporting the deck...boat manufacturers use the expanding urethane foam to support the 1/2" decking to give it the good solid feel. If you don't intend to use the expanding foam for floatation and deck support you should consider going with a thicker material, at least 5/8"
2. What will be fastened to the decking... if you are going to install pedestal seating you'll want a minimum of 5/8" thick decking.

 

[Barramundi NQ]

Thanks jigngrub, When I pull up the deck I'll see if there is foam in the boat. At the moment the 4 main areas (the fuel tank is in the middle with 2 f/glass covers) There is also an aluminium trim angle that forms a lip for the f/glass cover. I'm in two minds as to keep them, or just encase the fuel tank with the deck.
Of course I should foam the voids, and will front the cash to do so at the time.

One sheet of 1/2 "ply costs $50.5/8 ply (17mm) cost $73. Resin cost $195 for 20 liters (5 us gallons) to give you a guide on my local pricing.

Pedestal seating will be done in the friscoboaters style. His thread and oops extension really inspired me to tackle this project.

Thanks for you help

kerry

 

[jc55]

Jigngrub is right on, on everything. Yes, you will use at least 8 gallons of resin if not more, probably 6 sheets of 4'x8' including transom. I used all marine 3/4" ply @$80/ sheet, lapped the stringers 4' as mentioned on a 16' tri hull. No one here will discuss resin quality and brands vs. price, but they are not all created equal and some are night and day difference. Make sure you get a user's opinion on the resin you're using. There are resins that won't lay over corners, and there are some that will quite nicely.

 

[Barramundi NQ]

Hello jc55
I wish I could buy 3/4 marine ply for$80 a sheet! Here my hardware store has them listed at over $138 per sheet! Good to know I'm on the right track with my ideas.
As far as resin goes, in fact for almost everything I'll need to buy, one of my good friends is a shipwright and has access to bulk materials. I'll be picking his brain too.
thanks mate!
Kerry

 

[metriccrescentwrench]

If you have to replace the transom you really should be using 3/4 marine grade plywood for that at least. BCX will have voids which causes weak spots, that's usually not a big deal for decking but you don't want that in your transom. Marine grade plywood has zero voids and will be stronger than building grade plywood.