Advice for building a raft or dock

I'm doing searching and reading elsewhere on this forum and other sites, but I'd love any advice you have for this project specifically, concentrated in this thread.

Some friends and I need to build a raft (I use that term loosely, as we're open to other options), about 16' by 16' (roughly, could be slightly bigger or smaller) to take out onto a very very calm cove in the SF Bay. From what I can tell, vessels that size don't need to be registered in any way as long as they are oar-powered (please correct me if i'm wrong), so we won't be using any motor. Goals: we may need to transport it on a highway (so I'm thinking we might have to build in sections that can be connected at the launching ramp - this could make everything harder and require more floatation); then we will launch it and need to travel a short distance using oars; then we will float stationary for several hours (maybe using an anchor, maybe not), then travel back the same way we came. We need to float very comfortably with five people, coolers and bbq, and about 200 lbs (estimating over) of wood distributed evenly over the raft.

I'm new at this, as are all of my friends, so any advice you have is appreciated. Our priorities are to make it as reliable as possible, as light as possible, and preferabbly inexpensive (but that's behind the other two). Specifically: Should we be building a swim dock, raft, pontoon boats, skud, etc? how would you build/transport it (sections, one piece, etc)? what kind of floatation (this is kind of a school project, so school lawyers have to approve the raft, and the reliability of the floatation is probably a big part of that)? what materials and design for the frame and top?

I'm planning on searching the forums and web more for designs, advice, etc, and visiting Home Depot to ask questions there. But we're really starting from scratch to build this with very little previous experience - we really appreciate your help.

 

catamaran ??

may be catamaran ?
you can fill the 2 hulls with foam, bottles etc

Have a look here

http://www.cantierino.it/AEsperienze/PaoloProc/a.html

http://spazioinwind.libero.it/dinolucci/papera/costruzione.htm

http://www.cantierino.it/AEsperienze/Toast/Toast.html

http://www.cantierino.it/AEsperienze/Cat14/Cat14.html

sorry if they are only italian

 

a catamaran style is a possibility, but for how big we need, that may be hard for us to transport 45 minutes up and down a highway, even with a boat trailer. But it's definitely a possibility we'll consdier. Thanks.

 

all those catamaran are made to be kept on top of a car the two separated hull for moving them, surely is easier than similar size monohull !!!

 

I hadn't thought about that - great point. At 16' that would be very wide to take on the highway, but maybe we could go smaller or take backroads. Thanks for the advice.

 

Sounds like what is known as a Pontoon boat will solve the problem,.

While only 8ft wide for EZ trailering , the can be 20 to 30 ft long , so would have the Sq Ft for a party barge.

Outboard powered so all the USCG goodies will need to be aboard .

FF

 

Below are some pics of a barge hull. Very quick &simple to build. Obviously too big for you but scale it down and put a deck on it and you have a very stable, safe platform..
I belieave you can build a scow hull (what this is), quicker, cheaper (with less materials and have something more stable that can carry more load, than 'cats or 'toons.

 

Where are you going to find a "calm" cove on the SF Bay? Most of the bay can get pretty whoopin' most days. Well, at least in the summer.

That barge idea above might be the ticket. I'm betting you could hide a small outboard in there, take some oars and no one would be the wiser. Rowing rafts is no fun at all.

Or.. Does one of your buddies have an infatible dink with an outbord? Use that as a tugboat.

I'm dyin' to know what this plan is all about.

-jim lee

 

I won't elaborate too much, because many of the plans are still being worked out, but the idea is to build a raft for McCovey Cove to take out during the All Star Game this summer. Given the help I'm getting here, I'll definitely keep anyone whose interested posted on our project, which hopefully involves installing a very rough replica of AT&T Park on our raft.

 

Without gettigtoo involved..... I bet BEER is involved

 

I should also add this for anyone who can help: funding could be an issue for us. Because it's a school project, we need the school's lawyers to approve it. So we must convince him that the floatation is completely safe and reliable. And I think getting that floatation, and some other materials, could be fairly expensive (am I right)? So we are looking for someone or some company to sponsor us. We have a lot of people we're contacting, but if anyone on this board is interested in either just helping out or in funding the whole thing and putting a large advertisement on our raft that will likely be seen on national TV during the Home Run Derby, All Star Game, and other games throughout the season, please let me know.

 

How easy would this be to transport and launch? It looks significantly heavier than a pontoon boat, is that true? I'm intrigued, but it seems like a 16' by 16' scow hull could be a huge thing to deal with, and possibly harder to build than a pontoon boat. I'm speculating, so please correct me if wrong.

 

OK, what about this: we need something that's roughly square, so would building a 3-pontoon boat work? Basically, build a pontoon boat that transports on one car, then an additional piece with one pontoon that attaches with the middle other pontoon and is trasported separately. Wouldn't that work well?

 

Possibly make up 8' x 16' sections that can be transported one at a time to the rafting area, then linked together once your in position? Get your hands on a used trailer. They cost nearly nothing if you look in the right places. Then you can ferry the stuff overland. Or, for about $250 you can buy trailer axles. Get some axles, bolt them to the bottoms of your sections and just make trailers out of your raft parts themselves.

But then I wonder, how are you going to secure this on-growing raft? You have wind and current to contend with on the city front.

( Oh lord! I'm getting old. All I see are the concerns anymore. Sorry! )

-jim lee

 

I'm not positive, but I think it rarely gets very windy and the currents don't get very strong in McCovey Cove (and currents could be dealt with with an anchor, I think). But, I believe the issue you are raising is that the two sections will bounce and move a little independently (let me know if I misinterpreted you). I can't think of a real solution to this problem (my only idea is a system of wood boards that would attach to both sides under and over the platform, trying to keep them even - but that seems unlikely to work). It may be that we just live with a little unevenness on the two sides.