Soggy Floor - help needed

[deepsushi]

Fred,

I did not put the ribs back in. I did get a little bounce / deflection without them so I am going to pull the hatch back out this spring and glass in some stiffeners. I think I am going to use some 1 1/4 " pvc pipe ripped in half as the stiffener "base" and glass over it with some 1708.

I considered using one of the composite products as a core. However, the composites are a lot more expensive than plywood. Th original plywood lasted 30 years and it only failed due to the exposed plywood edges that allowed water to penetrate into the core.

Cutting the plywood into squares accomplishes two things:

1.) it eliminates any warpage in a full sheet of plywood.
2.) it is a much more efficient use of material. I recored the whole hatch with 2/3 of a sheet of plywood. If I utilized larger pieces I would of needed at least two sheets of plywood using large "whole" pieces.
3.) the theory of the alternating grain orientation is that it will prevent water intrusion between individual core pieces ( I am skeptical of this as every square was fully water saturated in the hatches I have done in both my 18 footer and the 23 footer.)

[strick]

The reason that all the squares got wet was because the factory just butted the ends of the squares next to each other...rather then leaving a gap and filling that gap with cabosil. The picture above is a very common sight on this board Leave a space and fill the gap and that wont happen. Also it will be stronger.



As far as composites go...they are supposed to be waterproof and we know at least temporarily they are but I've seen water trapped in foam over time... they are expensive and you cant just go down to Home Depot and pick up a sheet for 30 bucks. Another thing to think about is that this is new technology that has not stood the test of time...whos to say that boats with composite coreing will not crumble apart in 30 years? at least we know what plywood is capable of. That said I do like composits for some things and I have several sheets of corecell sitting in my shop waiting for something special to attach themselves to.

strick

[hermco]

Manufacturing with composites has been going on at least since the 1980s. If my memory serves me right every Contender and Intrepid built was a composite boat. I know for a fact the Contenders were.