jet drive draft

Discussion in 'Jet Drives' started by rick gray, Jul 27, 2016.

  1. rick gray
    Joined: Dec 2012
    Posts: 87
    Likes: 4, Points: 8, Legacy Rep: 30
    Location: port coquitlam B.C.

    rick gray Junior Member

    I have a boat project my own hull design and need to know maximum draft at rest for the american jet drive that is powered by 350 chev i heard 12" the hull has a 5 degree dead rise at last 5 ft forward of transom i was hoping to have a 16 inch draft aft at rest and plane up to 12 inch draft underway? there boat is 8ft wide x 22 ft long and weighs 5500 tro6000# LBs/Users/junegray/Desktop/P2130022.jpg
     
    Last edited: Jul 27, 2016
  2. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Your photos didn't post, can you retry?

    Calculating the immersed volume and it's distribution is the only way to figure out static draft. Are you doing this by hand or with a software package? Most software does this for you, of course with appropriate input parameters. If doing it by hand, you'll have to cope with the tedious, but necessary center of masses calculation.
     
  3. rick gray
    Joined: Dec 2012
    Posts: 87
    Likes: 4, Points: 8, Legacy Rep: 30
    Location: port coquitlam B.C.

    rick gray Junior Member

    draft

    Hello; i assume you can be consulted to do calculations? i can give a scale lines plan 1/4 scale by mail and have you do calculations with drive train weights and photos showing locations of engine and jet drive ETC. perhaps i could phone you for estimate? thanks Rick
     
  4. Barry
    Joined: Mar 2002
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    Barry Senior Member

    Your will be under the max limits that you want as long as the chine width with an 8 foot beam is around 80 inches.
    Our own boats with an 82 inch chine width, 12 degree v, would float in 12-14 inches of water and plane approximately at 6-8 inches depending on speed. Your 5 degree v will take a little less water.
    There will be some that say that you can run in 4 inches of water, but unlikely. In order for a boat to plane you need some bow up attitude which puts the stern deeper of course
    That being said, if you approach a short sand bar you can turn the boat into a drift just before contact so one side of the hull provides the lift and the turn will give a wider width ( to get a little more lift) presented to the water to get over the bar.
    All of our boats had the engine directly attached to the engine and the fuel tanks placed at the transom then forward.
     

  5. rick gray
    Joined: Dec 2012
    Posts: 87
    Likes: 4, Points: 8, Legacy Rep: 30
    Location: port coquitlam B.C.

    rick gray Junior Member

    jet boat draft

    i am still trying to dial in total weight of the boat ,the centre of bounce and draft. i am looking at 4000. LBs loaded . 35 cu ft for every 2000 lbs/ so about 70 cu ft of displacement? draft could be 6inches? what is minimum draft for an American turbine 309 jet drive. i think bow will rise when upon plane, and stern will settle.
     
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