Suppose a Hard Carbon Crackdown

Discussion in 'Boat Design' started by sharpii2, Jan 28, 2021.


What would happen to the planing powerboat hulls?

  1. They would simply be used less.

  2. Most of them would be scrapped.

  3. Some of them at least would be converted into displacement powerboats.

  1. fallguy
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    fallguy Senior Member

    Maybe so, but that boat isn't even a category B vessel. So, not really a seagoing vessel ftmp.
  2. KeithO
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    KeithO Senior Member

    It is a planing vessel. 25mph is not shabby at 9mpg. I have a G3 tiller steer boat but its not even close in utility and have not yet figured out how much fuel it burns with its 15hp motor.
  3. gonzo
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    gonzo Senior Member

    There are cars manufactured for much less than that. For example, the Hyundai Santro sells for less than $7,000
  4. Rumars
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    Rumars Senior Member

    Gonzo, please, I tried to stay away from the indian market, the cheaper end is for specially tailored versions that are not available anywhere else. The most basic indian version of the Kwid is ~4000USD (+taxes).

    The cheapest car you can get new in the USA is the Chevy Spark, at 14k and change. For the same money in Mexico you get a Duster, a much bigger car. The Kwid, wich is in the Sparks class, is selling from 8000, and the Spark is 10 000. The prices are not artificially low, the european ones are similar.
  5. Squidly-Diddly
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    Squidly-Diddly Senior Member

    my 1989 Toyota truck was $5995 but really more like $4800 due to tariff and a top quality build 100% Made In Japan with parts shared with Lexus models. It just didn't have any frills, or airbags. IIRC a 35mph crash was "likely fatal".
  6. gonzo
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    gonzo Senior Member

    That was my point. I compared a motorcycle to a car with all the required safety systems.
  7. sharpii2
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    sharpii2 Senior Member

    One idea I have been entertaining is an add-on hull segment which can be bolted onto the transom of a former planing powerboat. This segment would have rising buttock lines to ease the water flow back up to the surface to limit turbulent drag.

    The spray rails would still be there, as would the more blunt bow entry. But the LWL would be increased by maybe 25%.

    It would probably never be as good as a boat designed as a displacement power boat, but hopefully it would be acceptable as one.

    If I were doing such a conversion myself, I would want to add some kind of sail.

    The SA would be the product of Beam x Length.
  8. wet feet
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    wet feet Senior Member

    That ought to work,but it would add some wetted surface.
  9. goodwilltoall
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    goodwilltoall Senior Member

    Sharpil, that is exactly what was in mind to previous post about "extension". Some boats would work out better than others but most would have issues concerning:
    . Structural attachment process/strengths of extension
    . New rudder
    . Steering/helm.
    . New propulsion system/OB well/driveline.
    . Balance/trim

    Sure there r many more problems 2 resolve and the ones mentioned above would have 2 b well thought out. It would gain length which is almost always good. Would have to opinion that taking on such a project would just as well require a complete restoration of a very worthy hull and at a steep discount never the less be many man hours with costly fabrications/accessories.

    Still like the idea and a marinette would b a likely candidate since its aluminum and looks like it would transition neatly into a displacement hull, say the 28 converted to 38' would be impressive. Would imagine welding new longs/stringers thru existing frames to b a difficult job but should work as the hull itself seems stout n overbuilt. Have seen pics of huge trawlers cut in half n lengthened so its possible
    Last edited: Feb 6, 2021
  10. Will Gilmore
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    Will Gilmore Senior Member

    Adding a section to the transom could affect the trim, if the section were too light for the floatation it added. Not necessarily a bad thing. Like you wrote, some hulls would work better than others.

    -Will (Dragonfly)

  11. TCarpenter
    Joined: Feb 2021
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    TCarpenter New Member

    If we look at historical outcomes on artificial fuel use restrictions we see that privately owned craft did not tend to be used, and often sat locked away or abandoned while waiting for restrictions to end. WW1 and WW2 are excellent examples medium term restrictions being put in place. Those with Commercial motivations tended to look to alternative fuels so they could stay in business. They had a source of income dependent on their vessels, so engine replacement costs or upgrades were a fact of life, it was that or exit the market entirely. Private craft, however, weren't used very often and many were donated to the military, if they were of sufficient size, since they were essentially useless to civilian/non-commercial owners, plus it saved on mooring and maintenance fees. The cost to retrofit or modify a pleasure craft was prohibitive even for small boats, an example being gasifiers. Installing and using a gasifier in your 16 foot runabout, along with carrying the wood/coal was considered neither practical nor economical. Alcohol conversions needed to carry more alcohol to match the energy conversion of gasoline or diesel so the fuel consumption increased, not to mention, the shortening of the engine life from the alcohol solvent standpoint i.e. no lubrication properties. Then there was the costs of the conversion upgrades to the engine itself and the larger tanks in order to maintain the same range.
    For those who are fairly well funded boat enthusiasts, who actually use their boats, not just on holidays short, medium, and long term restrictions would be manageable, if expensive, seeing it's still a hobby. However, for those who own a boat "to own a boat", which tends to be the vast majority of boat would be straight to an alternate use, scrapyard, or neglected abandonment. Simply put, costs and requirements to install, train to maintain, and maintain a new system would not be feasible to the person who doesn't have a very specific use for the vessel or is just barely wealthy enough where it's not a concern in the long term.
    The only really feasible alcohol, from the energy/motor conversion standpoint, is n-Butanol, i.e. the stuff that gives Sharpie Markers it's odour. When run at 85% purity it requires no fuel system changes and produces nearly as much energy as gasoline. It can also be produced in 'bio-butanol' form, and it's also a diesel soot reducer additive.
    I suppose natural gas could be used, but it is extremely hard on engines for similar, lack of lubrication reasons, as alcohol; then there is the more frequent rebuilds which would further limit such a system, to those who are truly devoted to boats.
    hoytedow and Will Gilmore like this.
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