Help me design my jet boat Hull

[boatnutz]

Hi Guys, I have a 115 Evinrude E-Tec Jet I want to build a boat for and I would like to talk with knowledgeable hull builders about designing a Hull. I will be running shallow rivers so I would like to design for skinny water. My plan at this point is to build a jig out of 2x4 lumber and start by laying 2 sheets of 1/4" 6061 T6 aluminum 12' into the jig with the dead rise set at 8 degrees. I think it would be best to tac weld the 2 sheets of aluminum along the V. Next I would weld a piece of aluminum 1/2" 6061 T6 12' long 24" wide at the stern end tapering to a point toward the bow into the bottom of the V. I'm thinking this would form a nice delta pad, at this point I would trim off everything below the delta pad. I am planning on building a tunnel into the stern end of the delta pad as well hopefully with the stern end of the delta pad tunnel 3" above the bottom of the delta pad. The total length of the boat would be 18', the width would be 7', I know I'm not working with a lot of HP but I will some day repower with a 200 HP Optimax. The keel would rise about 2" from the front of the delta pad forward, the bow I think I will just have to wing, I can sort that out when I get there. The only part of the project I cannot envision is the Transom, anybody have any plan for a transom that will support a 400lb outboard ?
Thanks for any info !

[boatnutz]

Anybody have any idea where I can get a copy of Kaiser Aluminum's book Aluminum Boats 2nd Edition ? I heard this is a good book helpful to the amateur builder.
Thanks for any help

[boatnutz]

Hey guys I need some ideas for building a transom for my aluminum boat, anybody got any pic's or maybe a link to some picks ? I need some idea's for a transom that will be able to handle my 400lb outboard.
Thanks for any help!

[tunnels]

Transom !
Flat is weak ? well not weak but will bend easy Right so !!
The same material made into a shape will increase its ridged strength a lot so give the transom some shape .Using aluminium you can get it folded to the shape you want

I always make the backs of all my boats look really good becasue that all anyone is ever going to see .

I did a complete transom replacement on my glass boat and made it 99% from just glass has only a small patch of plywood of about 1 sqr foot where the motor fits and gets bolted on .

[boatnutz]

Nice work Tunnels thanks for the reply, I trailer my boat so I want a decent design I'm a little concerned about having a 400lb motor bobing around on the back of the boat.

[tunnels]

Originally Posted by boatnutz

Nice work Tunnels thanks for the reply, I trailer my boat so I want a decent design I'm a little concerned about having a 400lb motor bobing around on the back of the boat.

I changed from a tired old omc 70hp 20 inch to the V4 115 yamaha 25inch and the weight is not that much differant from what you got ,because my transom has shape its about half the weight of the old transom and splash well that i took out .
The motor has 450 mm set back , so all in all its is so much better then the old transom ever was !,i now have more cockpit room for fishing !
I have mu fuel filter and oil tank under the desk and the other side the battery and kill switch etc etc . Plus i went for Hydralic steering and that is magic . The boat is just 14 feet long and goes really well , changed the prop from a 13 X 16 to a 12 3/4 X 21 and goes like stink slower in the idle and 1200 rpms but get to 2000 rpms and things change 3000 rpms and its away 6200 rpms and its beautiful to drive !!, with the step back the power trim is beautiful to use and so easy to control and balance