What design is this

Discussion in 'Boat Design' started by fancyme, Mar 24, 2011.

  1. fancyme
    Joined: Mar 2011
    Posts: 3
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: South Africa

    fancyme New Member

    Hi

    I have just purchased my first plus 10 meter vessel and need help to decide if it is a displacement only hull or if it will plane.

    I have stripped out all the deck engine and toilets and removed all excess weight. I have left on the boat the upper superstructure to protect the vessel from the weather.

    After removing all the weight and pump out all the water dirt and sludge I found to my surprise that the chine of the vessel only enters the water 50 % of the way down the hull previously it was under the water

    The vessel is made of wood 14 meter at her water line and has a beam of 4.3 meter I estimate the current weight to be about 6 tons but after a refit I estimate that it will be about 11 tons.

    I would like to put Z-drive diesels in the vessel to keep the weight at the back and maximize accommodation below deck.

    I need to know if it will be worth while to spend the extra loot on two 200 hp diesel motors or will it make no difference to the speed as the hull speed if displacement is only 9 knots

    I have many questions but would like to start with this one

    First time using forum But has 30 years experience in Smaller powered vessels
     

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    Last edited: Mar 24, 2011
  2. cthippo
    Joined: Sep 2010
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    Location: Bellingham WA

    cthippo Senior Member

    Hard to say without seeing the bottom, but given what is visible and the HP involved I would guess that it is indeed a planing hull.

    Why Z drives though?
     
  3. fancyme
    Joined: Mar 2011
    Posts: 3
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    Location: South Africa

    fancyme New Member

    The bottom at the back is very flat.

    I am open to suggestions about the drives

    I have issues with very big following sea . I live on South Africa on the east coast and often we are out in 5 meter plus seas and I suspect that if I have a lot of weight near the stern this may help.

    I also find that wooden boats are prone to move a little when taken out the water and replaces and I find the fiddling around with alignments and A Brackets and the correct rudders a bit hard to get right.

    I also need accommodation for 14 people in bunks the more space the better
     
    Last edited: Mar 24, 2011
  4. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    It looks like a fishing boat conversion. The Miami area would be the first place to do some research on the old gal. As for power, as mentioned it's important to consider hull shape, of which we can't. Personally I think it's a semi plane design when lightly loaded, so it can get out to it's fishing grounds quickly, but once loaded up with a catch, she's full displacement mode.
     
  5. fancyme
    Joined: Mar 2011
    Posts: 3
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    Location: South Africa

    fancyme New Member

    Hi

    This vessel has aways been loaded with weight and weight added to improve incline test so that it could carry 56 passengers. I do not wish to load it very much.

    I am interested in the power to weight ratio and take into account hull speed.

    I was offered two 150 hp jet drives today and I am wondering if they could be used. The main issue is that these drive can run at 7000 rpm and I do not know where I will find diesels that will do the job

    Can you reverse a reduction box to speed up the revs and how will this effect power and the engines performance and economy
     

  6. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Jet drives are only efficient on high speed craft, which this will never be. I'm not sure what your propulsion type is, but we can reasonably assume it's a straight shaft, from logical reasons.

    Haul the boat and get a professional to first access the boat, then possably another to evaluate and engineer your proposed changes. It's not difficult to make yet another conversion on this craft, but you will need in person professional assistance.
     
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