(basic) Making a Boat Help!

[shandog999]

Hey everyone,

Ok so last summer I belt a floating dock using styrofoam as a flotation device but its very shaky and just not very good quality so this summer I would like to build a boat that will last and is quality. My idea is to either build two canoes and put a deck on top, making it fairly large or to make a pontoon boat with the same idea. I also found that a rigid hulled inflatable boat is a very intriguing idea and I would be interested in giving that a shot if anybody knew how to make an inflatable boat, such as what materials to use and what exactly to do. I guess I'm asking if any had any ideas to kick start the discussion to see if there are any better ways to make this boat? Preferrably, I would like it to be cheap and lightweight, but I'm prepared to spend quite a bit of money to make this happen so initially any idea is perfect.

Thanks for your time,

shandog999

[shandog999]

Also, I was wondering how to calculate buoyancy and what part of a boat's design makes it actually float? This is just for reference as I think it would be a great thing to know.

Thanks a lot,

shandog999

[mizzenman]

the boat will displace an amount of water that wheights as much as the boat. This is a natural law and can not be changed, it is called Archimedes Principle. The designer must se to it that the volume of the underwater body is as big as the wheight of the boat. if not the boat will simply setle on another level of flotation than what the designer intended.

volume calculations are made with Simpsons rule. Which is easy to understand mathematically, but kinda tedious to acctually use on a desing. Free!ship is a free designprogram that makes volume callculations.

If your out to save money id sugest you just buy a used pontoon boat.

[shandog999]

@mizzenman

thanks for the info about a boat's general design but buying a used pontoon boat is a little out of my price range, how could you build the flotation devices that are used on a pontoon boat?

thanks

shandog999

[Willallison]

Shandog
Probably the easiest and cheapest way to build a boat is to use the stitch-and-glue technique (plywood). The best way to make sure you're not wasting your time and effort in doing so would be to buy a set of stock plans. There are any number available, so you should be able to find what you are looking for. Give google a whirl....
For an introduction into hydrodynamics and boats in general, Dave Gerr's The Nature of Boats is a pretty good place to start.

[mizzenman]

Originally Posted by shandog999

@mizzenman

thanks for the info about a boat's general design but buying a used pontoon boat is a little out of my price range, how could you build the flotation devices that are used on a pontoon boat?

thanks

shandog999

Designing and building your own boat is generaly not reagarded as a way to save money. It's mostly done by folks that like to build stuff and have the money to spend on it.

Also the advice from the Australian above is a good one. Buy plans from a good designer. That will prevent many mistakes and in the end save you money.

Maybe its different for pontoon boats.

How about the blue barrels that are used for mushel plantations? If you could get your hands on some of those and lock them in a rigid structure.

[jim lee]

Here Shandog,

http://www.skagit.edu/cat_search3.asp?crs=676&cat=20082

This is taught on the Widby Island campus. (near seattle) Its cheap-ish and will go a long way in answering you're questions. I took this course and learned a lot!

-jim lee