Trying to learn about composite construction, a hypothetical build

Discussion in 'Fiberglass and Composite Boat Building' started by Smokeyr67, Sep 7, 2020.

  1. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    People getting excited about exotic materials in boats, especially planing boats, amuse me, the thing that will break first are the people on board, if the boat has to withstand high wave impact loads without breaking. There is no doubt that a stiff boat is a better boat, though, and I would say that at equal weight, sandwich construction is the way to get a better boat in terms of vibration etc, as well as freedom from "dynamic hook", which can make a boat ride worse. The problem remains, that point impacts becomes a vulnerability with thin skins. But using exotic composites to reduce overall weight, has its limits, inasmuch as while the thing may be more resistant to breakage, the people inside are not. I've often thought that in planing boats that are too small for (heavy) diesel engines, and it is is desirable to have a diesel, then that would be when the weight savings of such things as cored, high-strength laminates, could enable the heavier engines to be used, without penalty. What weight was added by a heavier, engine, being cancelled by a lighter hull. I can't say I have seen too many boats utilising that principle, and probably won't, as fuel injected 4 stroke outboards dominate powering of trailer boats. The attraction of diesels for such boats, has receded.
    bajansailor and Smokeyr67 like this.

  2. Smokeyr67
    Joined: Sep 2020
    Posts: 7
    Likes: 3, Points: 3
    Location: Australia

    Smokeyr67 Junior Member

    Thanks for the replies everyone, I'm really enjoying what you have to say.

    I've been attending the university of youtube, studying various web sites of the materials manufacturers and combined (or impelled) by your comments, I think I've learnt quite a lot.

    I'm inspired enough to buy some material (carbon, glass and aramid cloths, airtex core and vac bagging supplies and make a few test panels, just for giggles.

    Apart from the usual "stack weights on it until it breaks" type of test, I'm trying to think of a way to measure torsional strength. perhaps one end fixed in a vice, the other in a clamp, but where do I put the strain gauge???

    I've still got a few (thousand) questions, the first one is - if it was possible to build a powerboat fully from carbon fibre, would it be more susceptible to lightning strike than the same hull made from fibreglass?
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