deck structure

[gtflash]

what is the prefered method of internal deck structure? Is an internal moulding better than a ply deck glassed to the hull, ive read the rib international mag slaging off ply decks but surely they add to the rigidity... no?? Is it purely cosmetic?

ta gt

[Manos]

gt don't believe evrything you read

[Aging Youth]

Hi GT,

Although I am not a boat builder as I understand it there is 2 different manufacturing processes.

1. Marine Ply bonded to the deck as integral part of the design for both rigidity and maintenance.

2. Full glassed deck as part of the molding.

As to the difference in boat structure, weight is one part, rigidity the second, manufacturing process the third.

Marine ply decks can be replaced when saturated or damaged not sure about in built moulding. Perhaps a builder on the forum has a better answer. Hope it helps.

Regards

[Richard B]

The only reason I can think of for using plywood is if a builder couldn't be bothered to form the plug and moulds, spend time and money... so just bodges together a cheap ply deck in a few hours - and then covers it in GRP!

Having lit the blue touch-paper, I shall now disappear for the week!

[jwalker]

Originally posted by Richard B
The only reason I can think of for using plywood is if a builder couldn't be bothered to form the plug and moulds, spend time and money... so just bodges together a cheap ply deck in a few hours - and then covers it in GRP!

Having lit the blue touch-paper, I shall now disappear for the week!

Yes, do.

Have you any idea of the tensile strength of good quality marine ply? The ridgidity associated with thick sections? The ability to take the load of fastenings? Remember, there have been, and still are, some very substantial boats made from plywood.

Consider your wrists slapped.

[Cookee]

I'm mostly with Richard on this - In my humble opinion the only place for plywood is in the transom, its ability to withstand the crushing effect of bolting on a great big outboard and then bouncing it up and down is hard to beat - ask the person who had thier batboat transom made mostly of foam and then had it (the engine) fall off at the first rough race in Cowes!

The use of plywood strengthening in moulded floors can also be useful if the holes are sealed properly - I'm sure many people have seen water squeeze up through mounting holes in the deck before now?

As in every type of construction there are drawbacks, but the time it would take to make a sheet of plywood look good as opposed to moulding a floor is no contest as far as I am concerned!

[gtflash]

thanks guys, ive done a bit of photo research on the web and it seems the more commercial ribs tend to use the ply decks as far as i can see and the pretty ribs go for the mouldings... do you think its just for sales and cosmetics?