Noise from different hull types.

Discussion in 'Boat Design' started by marian, Jun 23, 2002.

  1. marian
    Joined: Jun 2002
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    Location: Europe

    marian New Member

    The European Commission is trying to bring in a Directive which to limit the noise from boats.

    Its a long story, so I wont bore you all, because the information I need urgently just concerns one aspect.

    The proposal has two different sets of rules: (1) One for outboards and sterndrives with integral exhaust. (2) Another for inboards and sterndrives without integral exhausts.

    Boat with engines from Group 1 will not have to undergo any testing. All the builder will have to do is buy engines which have been tested on a standard V hull and fit them.

    Boats with engines in Group 2 will either have to pay to have some authorised body to calculate (from Froude number and length to displacement ratio) that they are displacement boats. In which case they will not have to be tested.

    If they are planing or semi planing, an example of each model will have to undergo a by-pass sound test. The proposed standard (ISO 14509) reguires this to be done in weather conditions which the Commission has admitted "seldom exist in Europe" - for example a maximim wave height of 10 cm.

    In Europe we have many more inboard diesel boat builders than in the States. There are some quite large ones, but none who produce boats on the "turn 'em out in tens of thousands" way it is with some US companies. The vast majority are small ,or very small companies, (some one man bands) producing anything from between 6 to 200 boats per year.

    Once this proposal comes into force a manufacturer will not be allowed to sell a boat until the by pass test has been carried out and, because the required weather condition seldom exist in Europe, this could take months. Also if a rendezvous is arranged with an approved tester and the weather conditions prove unsuitable, the manufacturer will still have to pay for the guys time. That could happen more than once, with serious consequences for a small manufacturer.

    On some boats - for example Spanish llauts which are pointed at both ends - fitting an outboard would not be practical, so many little firms are likely to just go out of business. Others are likely to change to outboards or stern drives with integral exhausts, in which case Europe's marine diesel engine marinisers - all of whom are SMEs, producing between 100 and 8000 engines per year - are likely to be driven out of business.

    The reason for the different rules for outboard and inboard boats is because the Commission has been convinced that the inboard boat noise will vary according to the exhaust fitted. This is, of course, true, but we are arguing that the noise from any boat - inboard or outboard - is a function of many things other than its exhaust; engine, hull shape, hull dimensions, trim, prop wash, hull wash and hull slapping etc.

    There is a campaign on over here for inboard boat builders to only have to fit a tested, compliant engine in the same way as a builder of an outboard boat. The campaign is led by our own on-line magazine and the top Italian boating magazine Nauticaa.

    What we need right now is evidence - theoretical and/or practical - to demonstrate that it is unjust to have an easy route to compliance for users of one type of engine; especially since inboard engine boats tend to be the quiet ones, which dont annoy people.

    I'd be real grateful if as many of you as possible could respond, even if you are repeating something someone else has said. We need all the comment we can get.
  2. tom28571
    Joined: Dec 2001
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    Location: Oriental, NC

    tom28571 Senior Member

    I often think that our government is much too intrusive until I hear from someone in just about any other place on the planet.

    In my experience, boats with open exhausts make the most noise. That is expecially true of boats with hot (not water cooled) stacks. These are all inboards and include PWC's so I can see where they are coming from. Most of the people running loud boats, or cars for that matter, actually like the loud noise.

    I don't see that the type of boat enters into the noise equation though. The loudest boats in our harbor are fishing boats with big diesels and hot stacks that would be exempt under your regulations. It's not technically difficult to make any boat quiet enough to not be a nuisance though.

    Too bad beaurocrats are innocent of the ability to make a reasonable approach to a problem like this.
  3. Nomad
    Joined: Feb 2002
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    Location: Florida

    Nomad Senior Member

    zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz........Sorry WOW that's too much all at one time.

  4. Nomad
    Joined: Feb 2002
    Posts: 462
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    Location: Florida

    Nomad Senior Member

    But good and informative none the less
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