Help on materials selections for dinghy hulls

[stuart.cummings]

Basically, I'm researching materials used in hulls of small dinghies, rather than bigger yachts, so mainly concentrating on plastics and fiberglass. I'm basically looking for some information about pro's and con's of each (as I know both are in use for various different types of boats) and also if possible some data/materials selection charts to show the comparative strength/cost/toughness/brittleness of each. I have had a look and can't seem to find any materials selections charts showing plastics and fiberglass, so any help will be welcomed! Cheers

[stilloutoffocus]

i dont know about alot of the technical data youre looking for, but i can say that fiberglass will be loads easier on repairs than plastic will.

[fireballhank]

I would think your question needs to be a little bit more specific for us to help you.

First, describe what type of dingy you are thinking of building. While a simple pram or tender presents one set of building parameters, an international 505 presents something completely different.

Second, a little confused about how you intend to use plactics. While some companies are into 'rotomolding' different plastics they ae usually after building hundreds of copies in order to defray the upstart costs of building multiple centrifugal molds, etc...

In basic terms many dingy designs can be built from a decent grade marine plywood over either a strongback type male form or a simple jig- for instance the center stem of the boat.

Wooden boats can greatly benefit from having layer(s) of e or s glass to cover the wood and add structure, with tabs of uni or even csm to hold bulkheads, seats, and other parts in place.

A fully composte boat with foam core can be built again over a strongback style male form, or ideally in a female mold.

I know of no cost comparison chart, so think of it this way:
plastics, particularly rotomolded boats have extremely high startup costs but can provide the least expensve product if the number of cycles is carefully calculated.

wood construction, stitch and glue, stronbacking etc... can be the most effective one off construction method bt one must be careful not to over resinate the wood or covering glass as it ca become quite brittle.

If your skill level is above average then grp/foam core composite is the way to go. Moderate in price, bt much less if say 5-50 cycles are planned.