3.5m HDPE jetboat

got the fuel tank in now, i have run all the wires and i dont have to cut and lengthen any

i was going for two tanks but i think ill just keep one and have the other for storage and i can always put a fuel container in for the longer runs but i think 45 liters should be enough for most of my boating

 

i have also made the boss so i seal up the drive shaft, looks simple but took a bit of thought

 

Looking good.

Are you keeping track of your construction time?
How many hours have you put in so far?

 

knowing how long its taking me would be depressing

well every item made on the boat starts off as an idea, before that idea turns into a item, then i have to figure out how to make it, the pros and cons etc, long story short its a long process, its also my first boat so things take a little longer trying to work out what i need, some nights i can be in the garage for 3-4 hours and look at my progress at the end of the night and i might have only cut a couple bits of plastic, other nights things go faster.

I have also gone for hydraulic steering using pneumatic rams, trying something new instead of teleflex morse cables

 

It's not depressing if you are designing and problem-solving at the same time.

Also, with this material, you can cut, change and re-weld as needed, right?

 

haha yea, the first design was a bit average so i cut the front section off and had another go, i have attached a pic, this is when i thought slapping some sheets together would produce a boat, now everything i make/design i think of all the flow on effects before making it, I don't like doing things twice.

you can see how much i pulled the front in by the chines, also i started off with 12mm sides, its now 6mm halving the weight.

 

Interesting, we await further testing.

That adventure you took last time sounded unnerving at times.

 

I have presented myself with the perfect opportunity to fix a catastrophic cock up, some how i have managed to mount my engine about 40mm too far forward making the drive shaft too short, could take some thinking on how to resolve this issue, either move the stator forward or move the engine back, im thinking moving the engine back will be the easiest option, ill have a good look in the weekend

 

How well could you run bronze screws into a thick piece of HDPE, and expect them to hold?

Imagine the application for bent frames using wooden planks in carvel.
Frames are 1.25 inch thick, 2 inch wide, maybe 8 foot or even longer.

How long a piece can you get or, can it be but welded to be used as a frame?

I always was thinking for bent ribs, HDPE would be useful. No cracking, no rotting.

A piece the size of a rib, how easily will it bend into position with out heat being used?

Can you even get thick enough sheets? Perhaps you could go thinner, and wider for the rib?

 

Watching the video is impressive. I see people's hands holding on the outside edge or near outside of this boat? I wonder if with these rocks meeting hand and boat you could be tore up bad. Anyway to help prevent severe accident?

 

this is the river we boated, where Goat stopped we carried on about another 10-15 km got a bit more interesting after this

http://www.youtube.com/watch?v=urtQuqGSY4Y

 

For this size HDPE jet boat, if you want to go into production, design for a rotomold.

Mark Cat

 

i have made roto moulded boats before and don't trust the integrity of the plastic, buying sheet material from a world leader in plastic manufacturing is a much preferred option, also i wouldn't get much change out of 100k if i was to set up a workshop so its not very cost effective.

 

the packers i have made for the engine mounts,Turns out i was miles out. The last pic is the clearance from engine mount to the intake of the unit

 

updates???

I really like the looks of this boat. I like the thought of the durability and ruggedness this hull apears to have. Have you had any problems with rocks or jumping? Does the hull stay pretty rigid? I would imagine that being the friction coefitiant is less with hdpe than aluiminuim you should gain some speed? I would really like to see more of this, I saw your video of the mini but nothing of it running on the water- any plans to share more?