# Max raft capacity



## carvedog (May 11, 2005)

My buddy Matt posted this after an argument about raft capacity we were having on another forum. Someone was claiming that a 13.5 foot raft could carry 3,000 lbs - something like that. 

Too funny.



> Ok here we go:
> 
> 18 foot avon cargo raft:
> 
> ...


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## caverdan (Aug 27, 2004)

My 12' Vanguard has a sticker on it that says..............Max Gross Weight.......1100KG.

I've also heard it is unsafe to run rapids with your yellow stripe below the water.........lots of whistle blowing and turkey leg tossing..........I think it's some kind of law.


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## Randaddy (Jun 8, 2007)

We had six or seven grown adults and overnight gear for 2 people on my 9' Hyside. The oarswoman couldn't control it and we dump-trucked on a wall! Once the water line gets too high it's like a giant bag of sand!


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## randomnature (Jun 10, 2007)

Most 16' hysides can carry 10 people, guide, and guide's ego, which cretainly counts for a lot. It's all about displacement, no?


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## Chip (Apr 7, 2007)

*Draft Tables*

Most raft makers have something like this tucked away, although few of them make it available on the web. Anyhow, here's a link to the weight/ draft table on the Jack's Plastic Welding website:

http://www.jpwinc.com/catdraft.html

As a rough guide, I reckon that at max load, no more than one-third of the tube's diameter should be underwater. I have run boats deeper than that, and regretted it. As you increase the wetted area, you have to fight greater shear (i.e. friction with the water). The way to increase speed and manueverability is to increase the waterline while decreasing the wetted area. In effect, this means for bigger loads you need larger and/or longer tubes. Not exactly a revolutionary conclusion.

For reference, for an 8-day trip with two adults & doggo, my Jack's Stretch Flyer Cat (15 ft x 19-inch tubes) shown on the 'More Games with Frames' thread was loaded to a 6-inch draft, which is pretty near the 1/3 limit (6.33 inches). By trip's end we were more like 5 inches of draft.


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## TakemetotheRiver (Oct 4, 2007)

Randy, if you're going to say I couldn't control the boat, you should also mention that I was one of the 2 people who actually stayed on the boat when it dumped. Love the mini-me, but it's not a party barge.



Randaddy said:


> We had six or seven grown adults and overnight gear for 2 people on my 9' Hyside. The oarswoman couldn't control it and we dump-trucked on a wall! Once the water line gets too high it's like a giant bag of sand!


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## Chip (Apr 7, 2007)

Seven so-called adults in Mini-Me? So we're talking impaired judgement, contributory negligence, unexplainable failures of reason, maybe even _drinking_. 

How many cases of beer? That's a lot of weight, so you have to drink it really fast to lighten ship.

Or— maybe you could design a hydrodynamic dragbag that adjusts from side to side— like a canting keel on one of those mega-ocean-racing yachts.


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## TakemetotheRiver (Oct 4, 2007)

It was a mile or so before the takeout on flat water after a beautiful weekend- I don't think anyone was ready to go home, so for fun we decided to see how many people it would hold. And yes- I believe all of the factors you mentioned are attributable.



Chip said:


> Seven so-called adults in Mini-Me? So we're talking impaired judgement, contributory negligence, unexplainable failures of reason, maybe even _drinking_.
> 
> How many cases of beer? That's a lot of weight, so you have to drink it really fast to lighten ship.
> 
> Or— maybe you could design a hydrodynamic dragbag that adjusts from side to side— like a canting keel on one of those mega-ocean-racing yachts.


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## basil (Nov 20, 2005)

Cool pictures. Neat to see the kids having fun. 

On flat water with support boats around, sure, load it up.


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## Chip (Apr 7, 2007)

For massive overloading, the best outfit would be a good old bucket boat, since with the floor below the waterline, the space inside the boat will count as displacement volume. (As long as the floor is watertight.) 

As I recall, the weight of the load (_i.e._ gravitational force) displaces an equal weight of water, which acts on the displacing body as a buoyant force. Or is there some coefficient? 

Anyhow, it works.


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## rafterbrooks (Nov 6, 2004)

7 people in a mini-me! ya'll rock!

Capacity means the max you can get in the raft? Depends on the amount of straps you have!


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## peak (Apr 7, 2006)

22 people on a 16' Avon with a SB floor. we were tied up, but floating...


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## carvedog (May 11, 2005)

peak said:


> 22 people on a 16' Avon with a SB floor. we were tied up, but floating...


Looks like you needed beverage in hand to get on that bus.


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## rafterbrooks (Nov 6, 2004)

Yea baby! Can I join your group sometime?


peak said:


> 22 people on a 16' Avon with a SB floor. we were tied up, but floating...


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