Re: [omc-boats] Re: omc-boats-digest V1 #367

From: Phil Budne <phil>
Date: Wed, 24 Aug 2005 19:34:43 -0400 (EDT)

Lee wrote:
> Last night I sent some scans (which apparently are too large for the mail
> list server) of the original Evinrude construction process.

I found one of them, and have added it to the "lit" page.

> Here's what the paragraph said of the original construction and foaming
> process:
> "Rigid, closed-cell polyurethane floatation (equivalent to 73 life
> preservers) provides additional structual strength. Foaming is done under
> 250,000 lbs of pressure. Closed dies lock the hull in a steel embrace during
> the foaming operation."
> "Special foaming machines produce high-pressure foam twice as dense and far
> stronger than poured-in foam. It can't "work" or develop voids; won't absorb
> moisture, shrink. or pull away from the hull regardless of temperature or
> operating conditions."
> If you do the simple math that one live preserver could support an adult
> weighing 170 pounds x 73 then that equals roughly 12,410 lbs of floatation.
> I think Evinrude was more than meeting the floatation standards of BIA or
> whoever it was reasponsible for setting such standards..

One of the main innovations Ralph Lambrecht (head of the OMC Boat
Division, and a co-designer of the OMC/Johnson 17 hull) wrote about in
his "40th anniversary of the OMC 17 -- a benchmark in boatbuilding
standards" article, published in the July 2003 issue of "Boat & Motor
Dealer" was the flotation;

        Not just convenicnces, but safety too

        Between the flat interior floor and the bottom were two
        fiberglass hat-section stringers with alumninum plates molded
        in for the engin mounts, of which there were only two on the
        floor for th two-cycle V-4 sterndrive. The upper mounts were
        bolted to an aluminum beam running across the inside of the
        transom. The stringers were filled with high-density urethane
        form, as were all the empty spaces between the floor and the
        bottom. Plenty of room was left under the engine, making it
        easy to keep clean. The bilge-pump/blower-unit was mounted in
        a sump molded into the floor panel. If the water level ever
        got high enough to submerge the entire unit, both the pump
        and the blower on top of the sealed electric-motor housing
        would pump water out of the boat.

        The high-density foram in the bottom was mainly for support,
        but it also made the boat unsinkable. One of the side
        benefits of the OMC 17's unique bottom design was that it
        placed a large ammount of foam out in the sponsons on either
        side forward. And the deepest part of the foam near the stern
        between the stringers, giving the boat three-point boyancy.
        The result was that the OMC 17 floated level and upright when
        swamped. In fact, every boat that OMC designed in built in
        the 8 years they were in the boatbuilding business had this

        You could also leave the drain plug out of your OMC 17 and
        stay on board, because there was no place for water to go
        under the floor. In fact all five 170-pound people the boat
        had seats for could stay in the boat with the plug out, and it
        still floated with the hull-to-deck molding out of the water.
        This was a safety feature worth talking about. Virtually all
        fiberglass boats built in the early 1960's sank when swamped,
        or loaded with only their bows out of the water.

        Changing the Industry

        The OMC 17's remarkable floatation characteristics came to the
        attention of the American Boat and Yacht Council, and what was
        to become it's Hull Performance Project Technical Committee.
        In the early 1970's more than 1,700 people were dying each
        year in boat accidents -- mostly in boats less than 20 feet
        long. Clearly, the OMC 17 offered some promising solutions to
        this trend. One result of the committee's investigation was
        the enactment of the "ABYC" Standard H-8 for outboard boats
        under 20 feet in length," which required that all such boats
        float level and upright when swamped with their rated
        passenger load centrally located on board.

        This meant that passengers in a flooded boat would only get
        wet up to their waists if the didn't panic and they were not
        out in big waves. Such boats would also be stable when
        inverted, providing a large, unsinkable, and highly visible
        object to hang on to. Major boat manufacturers began to
        follow the standard voluntarily.

        Also in the early 1970'sthe Boating Safety Act was enacted,
        empowering the Coast Guard to establish regulations for
        recreational boatsq aimed at reducing the rate of boating
        fatalities and injuries. The causes of these accidents were
        analyzed, and it became apparent that the greatest reduction
        could be made by doing two things: increasing the availibility
        and use of personal floation devices, and making it possible
        for the passengers to stay with the boat, whatever condition
        it may be in. The level-flotation requirements of the ABYC
        standard were among the first federal safety regulations,
        along with a requirement that a PFD be carried on board for
        every passenger.

        These requirements addressed the causes of more than
        two-thirds of the boating fatalities, and were futher targeted
        for outboard-powered boats less than 20 feet in length -- the
        boats most frequently involved in fatal accidents. The rules
        were somewhat relaxed, though, for inboard boats, due to the
        difficulty of keeping a boat's stern afloat with an 800-pound
        engine located there. Inboard boats were required to only
        have "basic floatation," meaning that the vessel would have to
        stay afloat, but not neccessarily as a stable and level
        platform. At the same time, federal regulations also enacted
        standards for the fuel and electrical systems, ignition
        protection of electrical components in gasoline engine and
        fuel-tank spaeces, positive compartment ventilation and so on.

        Thirty years after the regulatory process was initiated, annual
        boating fatalities in the United States have declined from more
        than 1,700 to about 700.

        While it may be a stretch to give OMC all the credit for
        establishing these manufacturing standards, it's clear that
        they led the way. Someone had to show that it could be done.
        OMC produced more than 6,000 boats a year -- mostly inboards
        -- in the late 1960's and each one of them had level and
        upright floatation. The OMC 17 was the first of that line,
        and as such, it deserves our recognition.

(hmm, only the first two columns, and I will have typed the entire

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Received on Wednesday, 24 August 2005

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