Why only exterior grade?

[Jedo_03]

Re: Why only exterior grade?

Just a Newbie Mad-Cap Thought...
Why not use Styrene as a Core...???
Light-weight, Cheap, Easy to work with... Doesn't Rot... Bouyant... Available in slabs of any thickness required..??

 

[Yacht Dr.]

Re: Why only exterior grade?

I agree it would be crazy for the average Joe to try to form a hollow stringer. And it sure would be foolish cost wise to replace plywood with two more layers of glass and resin. Yd, would 4 layers of 1708 be sufficient on my 18' bow rider with 4.3 on the motor mounts? Quite a bit lighter than a 454

Just glass and no wood .. I think that would be too thin.

YD.

 

[mwe-maxxowner]

Re: Why only exterior grade?

I'm gonna build a motor mount out of wood that is in the shape of an L and glassed onto the stronger just like what was on there, and planning to glass it in four layers of 1708.

 

[Yacht Dr.]

Re: Why only exterior grade?

I'm gonna build a motor mount out of wood that is in the shape of an L and glassed onto the stronger just like what was on there, and planning to glass it in four layers of 1708.

What Wood are you talking about ?

The mount just goes into your wood cleat that is glassed to your stringers ?

Look.. a mount should be integral to your stringer system if your doing an IBO ..

Glassing a motor mount with such little profile to hang your motor on is not a good Idea. I dont care if 15 layers is on there. It only has to fail in the Primary bond !

Better get that mount Mounted or you could have some serious issues.

YD.

 

[mwe-maxxowner]

Re: Why only exterior grade?

The stringer section under my motor was 3 pieces of ply wide lammed together. Then there was an L shaped 'bracket' made of ply mounted on top of the stringer that the lag bolt for the motor went through, and all this was of course glassed over. That was the original construction, and I was figuring on 4 layers of 1708 over it.

Seen here. Except they are flipped around the wrong way here. What you are looking at was actually turned toward the inside of the bilge, not outward like it is now.

 

[ondarvr]

Re: Why only exterior grade?

Most boats that were designed, or redesigned in the last decade don't have wood in the stringers, many are just glass and glued to the hull. Wood is still used in transoms, but many builders have, or are, converting to other products. It's easier, faster, cheaper and sometimes lighter to make a pre-formed glass stringer system and just glue it to the hull.

 

[tpenfield]

Re: Why only exterior grade?

Most boats that were designed, or redesigned in the last decade don't have wood in the stringers, many are just glass and glued to the hull. Wood is still used in transoms, but many builders have, or are, converting to other products. It's easier, faster, cheaper and sometimes lighter to make a pre-formed glass stringer system and just glue it to the hull.

Here is a decent slide show on the completely wood-less construction at Southport boats . . .

Hull Design & Construction - Southport Boats


Some boats are still hanging on to the wood though . . . The folks at Formula told me that they still use wood on their smaller boats, and I was eying a Pursuit 310 at the boat show last year . . . all kinds of wood below deck on that thing.

 

[F14CRAZY]

Re: Why only exterior grade?

I used cabinet grade Birch for my Capri cabin bulkhead and doors. I found that when it rained the camper top would let in a drip that ran down the side of a bulkhead (wood was stained and polyurethaned). It has quickly started rotting and had a mushroom growing out of the endgrain.

I should have epoxy-ed it before coating with polyurethane but it goes to show that even a small amount of moisture can make cabinet grade stuff go to hell quickly

 

[Ned L]

Re: Why only exterior grade?

So I'm guessing that there aren't many people who have seen what happens if you put a piece of interior plywood that is left outside for any length of time? It's not long before you are picking up nothing but bits of veneer. Exterior plywood can sit outside for YEARS, ... until it rots.

 

[ondarvr]

Re: Why only exterior grade?

Here is a decent slide show on the completely wood-less construction at Southport boats . . .

Hull Design & Construction - Southport Boats


Some boats are still hanging on to the wood though . . . The folks at Formula told me that they still use wood on their smaller boats, and I was eying a Pursuit 310 at the boat show last year . . . all kinds of wood below deck on that thing.

Yes, the older designs that haven't been updated tend to stay with wood, as they redesign or build new tooling the trend is to go for non wood products.