Raft competition

Hey guys I've just joined to ask for some advice on building a raft. My company holds a raft challenge every year and my team is planning on entering this year, the aim being to build a raft and go paddling down a river and back up. First team to cross the finish line wins.

I've been put in charge of the project and my goal is to win
The rules state that the raft must not have any form of mechanical propulsion and you must sit on it, not in it. It also has to have 2 hulls.
My research leads me to believe that the fastest design is going to be as long as possible, and that a raft with outriggers may be faster than a catamaran.
So far I have managed to source some large industrial plastic floats, almost like drums.

Is anyone able to give me some advice on building the fastest raft possible?

 

I once won a raft competition with a catamaran made from beer cans a long long time ago. Dried them real well, used a heavy duty tape to seal the ends and tape them together into long tubes, stacked the tubes and taped them together 1 on bottom, 2 next, 3, etc. Cut some plywood for a hull top and tied together with 2 x 4.

We had a cost limit and it was a one shot deal. Boat was ultra light and fast enough to win against about another dozen entries.

 

Haha thanks. Fortunately we aren't that poor and can afford a bit better than beer cans
Albeit we can't go spending too much. Most materials will be sourced from inventory or scrounged/borrowed/scavenged from somewhere. Anything specific will be bought through the company. The race is for charity so there won't be a massive prize for winning.
There will be up to 50 teams taking part so planning is the key.
I forgot to add - there will be 6 people on this raft, 2 of which will be women.

 

This has been the subject of several other threads over the years. explore the forum to find previous projects of this sort.

The raft should be designed with the race course in mind. What conditions are expected on the river? Rough water, smooth water, will there be a current, are there likely to be snags or rock outcroppings, how long is the course, how wide is the turn around space at the half way mark, will the paddlers mind getting wet, will you use single or double paddles, can you use plywood to make the raft?

Generally speaking a long skinny raft will be faster than a short fat one. If it is to be a long one then the front to back distance between paddlers, about three and a half feet, will cause the boat to be near 24 feet long. It will become a rustic Dragon Boat of sorts. If it is to be double banked, paddlers side by side, then the raft will need to be at least four feet wide. The requirement for at least two hulls makes a catamaran the first thought. The cat may be more difficult steer in a straight line or not easy to turn. Mongolian fire drills are to be avoided so a little practice with the paddlers will be useful. You can practice unison and commands with six chairs on land.

Tell us what the conditions are and we old sea dogs will argue about the best configurations.

The whole deal sounds like fun.