3.5m HDPE jetboat

Discussion in 'Boat Design' started by HDPE JET BOAT, Oct 9, 2012.

  1. HDPE JET BOAT
    Joined: Oct 2012
    Posts: 81
    Likes: 5, Points: 0, Legacy Rep: 55
    Location: New Zealand

    HDPE JET BOAT Junior Member

  2. tomas
    Joined: Nov 2012
    Posts: 281
    Likes: 16, Points: 0, Legacy Rep: 147
    Location: California

    tomas Senior Member

    Your uncle says that he learned how to weld it as he was building it?

    How many hours did he put into the build?

    What is the total weight of just the HDPE?


    Thanks for sharing that.
    Looking forward to the sea trials.
     
  3. HDPE JET BOAT
    Joined: Oct 2012
    Posts: 81
    Likes: 5, Points: 0, Legacy Rep: 55
    Location: New Zealand

    HDPE JET BOAT Junior Member

    150 kg, many hours because its all new and had to make things to make the boat, ie folder, oven patterns etc.

    he started helping me make my boat and i was giving him lessons the weekend he was at home then went away and learn't the rest himself with the odd phone call, we got their in the end
     
  4. Scottym
    Joined: Apr 2013
    Posts: 11
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Sydney

    Scottym Junior Member

    Cool project - this and your uncles. A great material for a jet boat that is likely to see a fair share of shallow and rocky water.I saw back in about 1998 Mac boats in auckland build 3 small jet boats - pontoon style sides with planing hull. Bit ugly topside on them but I thought would be a great match up once "beautified" a bit. At that time they were selling the 3 off one was fairly well completed and the other two halfway. Not sure why they stopped development but maybe commercial reasons of R&D costs maybe.Also the motors then were heavier whereas now jet ski motors have changed all that. Interested to see it in action.
     
  5. HDPE JET BOAT
    Joined: Oct 2012
    Posts: 81
    Likes: 5, Points: 0, Legacy Rep: 55
    Location: New Zealand

    HDPE JET BOAT Junior Member

    http://www.youtube.com/watch?feature=player_embedded&v=J-E0mWeWuuY
     
  6. tomas
    Joined: Nov 2012
    Posts: 281
    Likes: 16, Points: 0, Legacy Rep: 147
    Location: California

    tomas Senior Member

    Congratulations to your uncle on that river run.

    Do you know how much the draft is under power?

    As you've pointed out, one of the advantages of HDPE is the ability to take some abuse. Has he hit any rocks yet?
     
  7. HDPE JET BOAT
    Joined: Oct 2012
    Posts: 81
    Likes: 5, Points: 0, Legacy Rep: 55
    Location: New Zealand

    HDPE JET BOAT Junior Member

    sitting in the water fully laden with two adults and fuel the chine is about 50mm 2" under the water, when on the plane the sides are dry.

    yea hit rocks, bounced off, his partner was worse off than the boat :D

    because the boat flexes a bit then its quite a soft ride, he is up loading another vid of the maiden voyage at the mo, its got rocks and a small push i think, ill post it when its live on you tube
     
  8. HDPE JET BOAT
    Joined: Oct 2012
    Posts: 81
    Likes: 5, Points: 0, Legacy Rep: 55
    Location: New Zealand

    HDPE JET BOAT Junior Member

    this is another boat built on the other side of the coast, these guys had a steering fail and hit a bank at about 80 kph, didnt damage the boat but the driver still walks with a limp.

    http://www.youtube.com/watch?v=oinA0i9QeXI

    Quote Glen: the test run... well that's been done a few times.. the boats nearly a year old.. it made me want one!! just a waiting game now until i get mine!

    being plastic you hardly even feel it scraping the rocks.. when you drive it up the bank you have to pick a spot it wont slide back in the water.. its had a few crashes with no real repairs needed. you look at the bottom and you would hardly no its cut a few corners where there has been no water..

    i see people are lining the bottom of there boat with Hope.. this one is just completely plastic

    price wise its about the same as alloy. maby a bit harder to work but that's just time..

    has a memory wanting to be flat again so any dents or sag from sitting on the trailer will disappear when the weights off it. so will set back flat for the next trip.

    the welds seem to hold up to all abuse that has been thrown at it.. hit a bank nearly head on after the steering cable snapped. the go-pro said it wad doing 80km. the impact was hard enough to tear off the fuel pump and filter. also tear a dirty great hole in my leg from hitting the dash.

    the best thing to see after that crash was it left one little mark in the plastic by the nose of the boat.. from other experience's it would have smashed most other boats I've been in..

    the boat was going the next day.. and I've still got a limp..

    performance well it runs like a gangster late hours of the night after a gun shot.. more fun than a lollie shop.
     
  9. tomas
    Joined: Nov 2012
    Posts: 281
    Likes: 16, Points: 0, Legacy Rep: 147
    Location: California

    tomas Senior Member

    Thanks for sharing that.

    The statement "has a memory wanting to be flat again", is referring to flat material that has been welded and not to HDPE material that has been formed/shaped with heat, is that correct?
     
  10. HDPE JET BOAT
    Joined: Oct 2012
    Posts: 81
    Likes: 5, Points: 0, Legacy Rep: 55
    Location: New Zealand

    HDPE JET BOAT Junior Member

    it comes in sheet form from factory, if its bent by hitting a rock or anything then it will return to a flat sheet again, my uncle made a strip bender that heats the plastic so you can bend it, once it cools then it stays in that shape.
     
  11. tomas
    Joined: Nov 2012
    Posts: 281
    Likes: 16, Points: 0, Legacy Rep: 147
    Location: California

    tomas Senior Member

    Any larger design constructed with flat sheets would have to allow for this expansion then, so that if a HDPE boat is partially exposed during a hot sunny day, it will distort due to expansion. Once it cools to normal temperatures, it will return to it's original dimensions due to the material memory.
     
  12. HDPE JET BOAT
    Joined: Oct 2012
    Posts: 81
    Likes: 5, Points: 0, Legacy Rep: 55
    Location: New Zealand

    HDPE JET BOAT Junior Member

    more on the grill today, after my steel supplier under supplying the bars, cutting them out of MILD STEEL instead of bisalloy 400 and after all that they dont do a 5mm sheet which is what the intake was designed around :mad:

    then i finally got my bisalloy bars they once again under supplied the bars, i was one short so back the drawing board and it worked out at 11.5mm spacing instead of the 10mm i was after, needless to say i got their in the end

    This a new idea i have being thinking about, theory is the bars being a different thickness then the stones shouldn't jam in between the bars the same because its not a flat surface. not sure if its going to work or not, i guess time will tell.
     

    Attached Files:

  13. tomas
    Joined: Nov 2012
    Posts: 281
    Likes: 16, Points: 0, Legacy Rep: 147
    Location: California

    tomas Senior Member

  14. HDPE JET BOAT
    Joined: Oct 2012
    Posts: 81
    Likes: 5, Points: 0, Legacy Rep: 55
    Location: New Zealand

    HDPE JET BOAT Junior Member

    yea, thats the welder i have been using, why do you ask?
     

  15. tomas
    Joined: Nov 2012
    Posts: 281
    Likes: 16, Points: 0, Legacy Rep: 147
    Location: California

    tomas Senior Member

    Your thread has shown me that this is an approach worth trying. Since I'm not in your neighborhood to rent or borrow, I'll have to purchase one. It seems to have the appropriate heating for thicker plates, unlike the smaller units that are used for feeding rod with thinner material.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.