Bertram 20 maximum engine weight

Discussion in 'Boat Design' started by Greenhead, May 10, 2016.

  1. Greenhead
    Joined: May 2016
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    Greenhead Junior Member

    Hi all,

    This is my first post so g'day to you all.

    I have an Australian hull call the huntsman. She is a 19'6" Raymond hunt design almost identical to the Bertram 20'.

    I have just picked up a cheap and good condition 165hp Volvo penta which weighs a whopping 430kg.

    My question is, do you think this weight is acceptable for this type of hull? What is the biggest motor anyone has seen in a Bertram 20'?

    My thinking is that it is on the upper end but should be okay because of the deep V (more volume below the chine) and it came out of the factory with an onboard. I'm guessing a mer cruiser of some kind.

    Any thoughts would be really appreciated.

    Photos attached.

    Cheers
     

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  2. Mr Efficiency
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    Mr Efficiency Senior Member

    Heaps of the Bertram 20's (Pride Bahia Mar was same hull) had Mercruiser 165hp back in the day. That was a 6 cyl iron block. You should not have too much problem weight-wise. I take it you mean you have a Volvo Penta petrol engine, not the diesel, which certainly weighs much more than 430kg.
     
  3. Greenhead
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    Greenhead Junior Member

    Thanks for the response. No I mean the diesel. It's the tamd40b turbocharged.
     

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  4. Greenhead
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    Greenhead Junior Member

    Marine diesels are so expensive so I just snapped this one up. Will probably go for it and see how she floats. Can always swap it out for another.

    I'm going to stay true to the I/O configuration.

    Was that 165hp a 6 cyl?

    Cheers!
     
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    This says 1147 lbs : http://www.boatdesign.net/forums/powerboats/volvo-tmd40a-weight-6495.html

    That is in the same territory as a V8 petrol sterndrive, which would be too much for the boat, I'd say. You are going to have a stern heavy boat, and that type of hull is already inclined to run nose-high. The original choice of a petrol 165 or 4 cyl 170 hp would have been somewhat lighter. Marginal at best, I'd say, because of the weight. See if you can find one of those old boats with a V8 sterndrive, on the web, I doubt there'd be any though.
     
  6. Greenhead
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    Greenhead Junior Member

    Ah I think you are right. I might have to face the facts!
     
  7. Mr Efficiency
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    Mr Efficiency Senior Member

    See of you can track down the weight of the old mercruiser 165 6 inline sterndrive, and compare that to 1147 lbs. They seemed to handle that engine OK, but much more weight and things change. Forum member "powerabout" might have the specs, I can't find them after a quick look.
     
  8. Greenhead
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    Greenhead Junior Member

    Great thanks for the advice. I may fork out for a modern unit like a lightweight steyr and flick this one.
     
  9. Tad
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    Tad Boat Designer

  10. Mr Efficiency
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    Mr Efficiency Senior Member

    I'm thinking it is not worth it to be shelling out big bucks on that boat to get a diesel sterndrive. I'd reckon any diesel sterndrive, or even jack-shaft set-up will be too much weight, especially if the boat will be called upon to haul any sort of load. It's a deep vee and successful diesel powered ones that size are very hard to find. None come to mind. 22/23 feet you might find a few, that particular engine was installed in the venerable 23' Shark Cat back in the day, as an economy measure, but was a real slug. SImilarly I've heard of them in the Formula 233 even, which also turned it into a boat that, like the cat mentioned, had dismal performance, and unable to use the real strength of the boats, which was a high sustained cruise speed in offshore conditions. You'd have no trouble selling that engine, and what you do to repower is either a petrol sterndrive, or even go outboard, although I'd be doubtful about that if the transom deadrise is the 24 or 25* , might be OK if 22. The problem would be the boat becoming tippier as weight was taken out of it.
     
  11. Greenhead
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    Greenhead Junior Member

    Okay thanks for this. I am now looking at the mer cruiser petrol 3.0 135hp. Brand new package for around 14.5k. Good value I reckon. You think this would work?
    With alpha one leg.
     
  12. Mr Efficiency
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    Mr Efficiency Senior Member

    Need more hp, I think. Those old boats are best with more horses behind them.
     

  13. whitepointer23

    whitepointer23 Previous Member

    V8 mercruisers were popular in the 20 ft huntsmans and bertrams. The 135 will work too hard . The best setup for you is a v6 volvo or mercruiser. Both u se the same 4.3 chev which is a 350 minus 2 pots. Volvo 40 a is a good anchor.
     
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