I need some help with hull specs

Discussion in 'Boat Design' started by aktmboyd, Apr 6, 2014.

  1. aktmboyd
    Joined: Oct 2013
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    Location: Kimmirut, Nunavut

    aktmboyd Senior Member

    I have a project under way and I need some professional help with it. I recently bought this boat and I am considering repowering it with either a jet drive or an ib/ob, preferably the jet drive. For several days now I have been trying to get a hold of the manufacturer of the boat but they will not answer the phone(you have to leave a message which I did multiple times) or email, which I di aswell. I need to figure out what the heck I have here for the jet manufacturer. The loa is 22', lwl is 21' beam 77" baw 70" it has rounded chines but a slight v bottom. There is a delta that is about 2' wide and it extends about 5' forward. Th hull is heavy frp about 3/8-1/2. There is no soul, no stringers and there is only one bulkhead about 5' forward of the transom. It has three 1 1/2" x 1 1/2" keels the middle one runs from the bow and ends at the front of the delta the two outer ones run forward from the transom about 7'. The gunwales are about 30" high form the inside bottom of the boat. I would like to try and figure out a rough weight of the hull(less the ugly 3/4" ply cabin), displacement and whatever else is important to know when you are repowering a hull. Thanks for any help you can offer.
     

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  2. aktmboyd
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    aktmboyd Senior Member

    sorry about the crappy pictures
     
  3. Mr Efficiency
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    Mr Efficiency Senior Member

    Your pix tell the story OK, I think. I would be doubting the value of switching to a jet drive, your comfortable cruising speed in that hull would be slower than what a jet would be efficient at, imo.
     
  4. aktmboyd
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    aktmboyd Senior Member

    The reason for the jet is our 30' tidal fluctuations and the van size boulders hidden within it. What style of hull would you call this. Also the single sixty planes the boat and the twins that I have move it along at a surprising rate.
     
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    It is a round bilge planing hull by the looks of it. You would be adding a lot of weight to what is a not overly beamy boat, with a jet powerful enough to reach the sort of speeds it would be reasonably efficient at. The lack of chines only makes that worse. Do you find it a good load carrier ? If not that great, it will be worse with an inboard. You also have a sizeable job, and cost, to convert, it might be better to change boats.
     
  6. aktmboyd
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    aktmboyd Senior Member

    This boat in particular last year done a very long round trip to a soap stone mine, I think it was 400ml round trip. Four guys fuel equipment and gear plus 2000lbs of stone on the way home. My brother I law was one of the four. I was told yesterday that the boat barely squatted with the extra weight. Still planed with the twin 60 evinrudes.
     
  7. Mr Efficiency
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    Mr Efficiency Senior Member

    Depends whether you are on open waters that chop up, I suppose, I would imagine you cruise around 15 knots or so with your present power, much faster than that might get uncomfortable. Not the "right" speed for a jet, too slow, I think you fuel usage will be likely more than those outboard(s). But if its flat water a lot of the time, the equation changes.
     
  8. aktmboyd
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    aktmboyd Senior Member

    I'm gonna say more like double that speed with the twins it is one of the faster boats in town here. Lets put it this way I have a freighter canoe with a 55 Yamaha tiller that does 23 GPS mph. Last year my wife dog and myself where out in the canoe and got passed by the same kind of hull(there are a number of them here) with a 90etech on it with probably five+ people on board like we were standing still. It pissed me off and I told my wife that I want one of those.
     
  9. Mr Efficiency
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    Mr Efficiency Senior Member

    I'm not buying your estimate here ! I'd say if you were cruising at 30 knots with those engines, the laws of physics have been suspended ! Flat-chat you wouldn't reach that, imo. :D
    I think your decision largely depends on what conditions are, sea state wise, on average. It you are generally operating "backed off", the jet idea becomes less attractive, however if it is like a millpond most of the time, it could be a goer.
     
  10. aktmboyd
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    aktmboyd Senior Member

    I know it's stupid sounding but it happened to me. Maybe the flat bottom helps. I gotta get the boat out of the snow take my telehandler flip it over and get some better pics here. I'm not shooting ya a line here for some reason the boats work the hull is made by Lake Winnipeg Boat Works. My freighter canoe I think it listed weight is in the 650 lb range 22' long and a gotta be about 40" wide. It moves good and I was passed by a boat load of people and 40 horse more
     
  11. aktmboyd
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    aktmboyd Senior Member

    Goin to the seas around here I guess it's like anywhere else. Would be nice if it was always glass flat easier to see the seals that way. And using a scoped rifle out of a boat is an art form that I have not mastered yet like the local Inuit people here. So when there are waves I miss lots.
     
  12. Mr Efficiency
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    Mr Efficiency Senior Member

    The flat bottom certainly helps load carrying, not so much speed though. So, what are the conditions, rough or smooth ? Changing to jets alters the handling characteristics of boats, basically for two reasons, the line of thrust is higher, and you lose some lateral plane aft, which means if the boat has any tendency to bow steer, you will find that amplified. You might like to consult the boat's builders for an opinion, they may know of jet versions of the hull, and performance of same. And how much hp you may need to install. Would need to be well over 100 hp imo.
     
  13. Mr Efficiency
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    Mr Efficiency Senior Member

    It might also be an idea to price jet drives that would suit, they are not cheap items.
     
  14. aktmboyd
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    aktmboyd Senior Member

    It's not really flat like pancake flat there is a small amount of v to it. The v comes right of the delta and continues outward till it meets the chines.there is so much ice and snow around the boat that it is hard for me to get any quality pictures. Sorry if I led you to believe about it being a flat bottom boat. About horse power it's in the 300hp range and 500 ftlb torque goin 5.9L cummins or maybe more. I have also been talking to the rep at American turbine jets. Prices are very reasonable. But it's the hull I need to know about and the manufacturer will not reply.
     

  15. aktmboyd
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    aktmboyd Senior Member

    You gotta guess on it's weight ?
     
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