Pontoon 600

[gordanm]

Dear fellow forum members. I would like to build plywood pontoon boat with semidisplacement catamaran type hulls. LOA 6 meters.
I came up with design I attached (Delftship). As it will be obvious from design itself, I'm not naval architect nor I have any formal knowledge in boat design.
I just couldn't find such design on internet so I decided do give a shot myself. In Delftship file I have three set of hulls, each in separate layer. My target hull type is in layer Pontoons_displ_2
My desires can be summed up in following characteristics:

LOA: 6 meters (20 feet)
Beam: < 2.5 meters
Semidisplacement type catamaran hulls
Modest engine (up to 15 HP, four-stroke, weight around 45 kg)
Expected speed around 10 knots
Ability to carry 4 people for most of the time (up to 6 occasionally) for day outings, 99% of the time in the 3-5 nautical miles range from berth.

I would like experienced boat designers to comment on my design. What are the flaws? Am I on the right track to achieve characteristics i desire?
Should I trash this design completely?

Hot to construct motor well for centrally mounted engine? What material. How to connect it to the deck?
How many cross beams should be there? How big? How to connect them to the hulls? How do I make deck as lite as possible but strong enough (of course).

As you see, I have many questions so I would prefer to buy such design. It's just I couldn't find it so far.
But, if there is no such design I would still like to build it (it seams that boat I attached here wouldn't sink at least) :-)

Thank you very much for your answers.

[gordanm]

Does anyone have info of availability of similar design? I built one boat from plans purchased on internet already (Hartley Scamp 15) but I couldn't find design similar to one I presented above.

[Kaluvic]

Hey gordanm
I couldn’t open the files...the computer didn’t recognize the file type.
I'm sure you’ve searched but I'll do one as well and see what I find.
I'm interested because I've been thinking about building 6 meter out riggers.

[gordanm]

Originally Posted by Kaluvic

Hey gordanm
I couldn’t open the files...the computer didn’t recognize the file type.

Those are Delfthip files. In order to open them you should have Delftship application installed on your computer.

[SamSam]

Here's a few places that might help...

https://www.boatdesigns.com/departments.asp?dept=7

http://www.svensons.com/boat/

[Kaluvic]

Those are some excelent links....thanks SamSam

[gordanm]

Since no one commented any possible problems with my design, I assume I can start building this pontoon/cat boat?

[PAR]

By your own admission you have no design or engineering skills. You have generated a pretty picture of what looks to be a boat. Now how about your thoughts on the longitudinal stiffness, necessary for those hulls? Cross beam connections? Target weights, targeted S/L ratio, a reasonable set of scantlings with understandable safety margins? Have you given thought to any of this?

Frankly, no I don' think you're ready to build this boat. I don't think you have the structure anywhere near what is needs to be, let alone understand the differences in the data, generated from your different hull models.