Im building my first raft and need advice

[mordacil]

sorry if this is a repost, but I coundlt find another thread clsoe enough to it. Im building a raft to carry 4 people down The Ocmulgee River in central GA. My design is a 12'x8' wooden frame atop 4 or 6 (I only have 4 as of now) steel drums. the frame consists of 4 vertical 2x4"x12' and 4 horizontal 2x4"x12' boards bolted together with the barrels strapped with steel cables between the 2 12' on each side with one barrel closer to the front and one to the back (if 6 barrels, one would be in the middle too) so its almsot like a pontoon. the wood would weigh about 120lbs, and about 640 lbs of person, and I have no idea how much food and supplies for 5? days would weigh, I'm guessing 50lbs. so in your experience, what are the flaws in this design (if you think you can picture it by my description)? can 4 steel drums hold 800 lbs afloat? and I was wondering if you had any ideas as to how I could make the raft stay oriented with the "bow" downstream (the direction of travel).

[djwkd]

If i were you i would use the 6 plastic barrels-or in the middle make sort of casings into which you pour pour-foam and place in old plastic bottles.remember-follow your dream!!!

[Bergalia]

Mordacil... Am I right in assuming you are talking of the 40 gallon type of drum (used for oil etc). If so four will give you plenty of bouyancy...two more will give you a good 'safety' margin.
Attaching them so that they stay in place is a different matter. Broad luggage straps - with rachet tightners may be the way. But certainly they'll need to be firm as they will no doubt get some bouncing and battering on your journey.
As for keeping her 'bow' downstream - a broad sweep oar as rudder will help, and maybe some form of trailing 'kedge' - a bucket towed behind or a loop of rope. (Either will be prone to snagging on submerged rocks, logs etc) But allowing for this should keep you pointing the way you want to go.
The other thing is to build some form of shade for your passengers to prevent them from suffering sunstroke - or a soaking in the rain. Nothing too sturdy in case of a collision in which the structure collapses causing worse injuries than would a simple wetting. And don't forget. Life jackets. Wear them at all times. Good luck.

[timgoz]

Don't froget your H2O for consumption's weight. Four people for five days at 1/2 gal per person a day is approx. 80 lbs.

An anchor with 100ft. of sturdy line might prove valuable. A knife to cut it away in an emergency should also be carried.

Any commercial vessel traffic on the river should be a concern and met with only after much thought.

Have fun.

TGoz

[SamSam]

Fresh water weighs about 62# a cubic foot. However much volume your barrels displace is how much they will support. For example, if your barrels are 4 cubic feet each, each one will support 248# fully submerged or 124# half submerged. Sam

[mordacil]

my idea included two shorts "masts" that would support a rope over which a tarp would hang, fastened to the sides of the raft as a tent-like shelter. aside from daily water, we had in mind the idea of purifying new supplies of water as needed using a combonation of the treatment tablets and boiling. thanks for the ideas, I wouldnt have thought of those, thats why i came here.

[djwkd]

yes,thats a good idea,like the floating neutrinos.in my plan ive done the same thing pretty much,but i found a website yesterday which sold them.it was about 7.00 GBP for a single 10x11' tarp.Quite cheap.I checked the postal charges to come intgo the uk and it was about $120.00 (approx 90.00 GBP)!!!

[Bergalia]

Originally Posted by mordacil

... aside from daily water, we had in mind the idea of purifying new supplies of water...

I believe that the allies outside Tobruk overcame the water shortage by straining their own urine through a sock...So it's possible their breath led to a rapid retreat by the Panzers...

[djwkd]

Bergalia,if you dont mind me asking,what is that picturee thing of,and what are YOU planning to build/have built/are building/own???

[mordacil]

I was also wondering about waht kinds of food to carry and how to store it. The simplest answer I could think of was to use military MRE's, but that is not the cheapest answer, and I plan to go as cheap as possible. I also though of canned foods such as the cheap tuna and meats like spam, and also ramon noodles, essentially college kid food, which I think might be heavier, but are cheap, easily stored, and easily prepared. waht do you think of this food and suggestions are appreciated.

[mordacil]

this is my design. I was considering some sort of sail to help propel it. does a sail on this sound reasonable, and if so, any ideas?

[SamSam]

Originally Posted by mordacil

this is my design. any ideas?

On the end view of the barrels with the cable strap it looks like the barrel will be able to sort of roll a little bit back and forth. If you had two more 2x4s on the bottom of the wood structure, parallel to the barrels, more or less directly below the end view 2x4s you show, and contacting the barrels, that would stop any side to side movement. It would be best if the barrel didn't contact the deck at the top of the barrel, just at the two parallel 2x4s.

[Bergalia]

Originally Posted by mordacil

this is my design.

Once more SamSam weighs in with practical advice. If I can suggest a slight modification to your floats - try and attach a narrow 'sole' (ten inches wide or so) to the bottom of the barrels - something like a ski linking the fore and aft floats - to cut down a 'double' bounce should you hit hidden snags. A cross member (though adding weight) will give extra rigidity. But apart from that - the design seems fine. As for sail - why not. A dipping lug or lateen might do the trick and can be rigged from your spar and awning. Go for it

[SamSam]

The way you show the barrels against the bottom of the plywood would mean that all the 2x4 structure would ''hang'' from the plywood in the finished raft. It doesn't serve much purpose like that and probably would eventually work itself loose. The ply would also probably get humps over the barrels as the weight of the structure pulled the rest of the ply down. If it's done as I suggested in reply #12, the whole conglomeration would be supported by the barrels in a structured way.
I would also add 1 more 2x4x12 on the top in the center to support the plywood every 2'.
There's also a small problem with the unsupported ends or sides of the ply, depending on which way you lay it. They could be helped with scabs screwed on beneath the plywood or if you changed the spacing of the 2x4x8's to be 4' apart, 2x4 blocks could be attached on top of them to bring them flush with the top of the 2x4x12's and the ply would then be solidly supported all over. Sam

[mordacil]

sorry, the 2x4x12s were meant to be close enough to sit on and be supported by the barrels, thats jsut imprecise drawing on my part. what are "scabs"? the 2x4x8's are positioned so as to hold the barrels from sliding forward or back as the straps or cables hold them from going to either side. is using chemically treated 2x4s necessary? and I want to use OSB board for the deck because it is cheap and water resistant.