Someone's gotta know the answer to this:

[Labrat]

How long would it take for four adults to row across the Mississippi on a raft?

 

Any takers? I have no clue but it will help me as a reference.

 

(Ah the things you can ask on a gamers thread and not get scowled at)

[Lethosos]

Re: Someone's gotta know the answer to this:

 

Well, I personally have no idea, but... you could do some simple trig to figure it out. Hrmm...

 

Get the speed of both the boat (in calm conditions) and the river in question. This will help us visulize the problem as a right triangle in a larger one. Basically, use the Pythagorian Theorem to get the hypothenuse's length; this is the speed that they're actually going at.

 

Once we do that... we then use the smaller triangle to measure the larger one--just determine the multiple of one side to the distance of the equivilent larger side. I think there's another bit of calculation after this, but I think you don't need it--I have this urge to try and get the distance of all the sides represented.

[Erkenfresh]

Re: Someone's gotta know the answer to this:

 

Take the width and divide by their rowing speed. It doesn't matter if the river is going 0 or 100 MPH (well, 100 MPH might tip the raft over but you get the idea).

[Erkenfresh]

Re: Someone's gotta know the answer to this:

 

Judging by Mapquest, it looks like the Mississippi River is 0.5-1 mile wide depending on where they would cross.

 

I'm not a rower but 10 MPH seems reasonable for 4 adults. So, 3-6 minutes?

[AlHazred]

Re: Someone's gotta know the answer to this:

 

Well, the Mississippi River varies between 20 feet wide (at its head coming out of Lake Itasca) and four miles wide (at Lake Onalaska in Wisconsin).

 

More details on the physics of rowing can be found here and here. I believe a fast rower can make about 18 kph, or about 11 mph. You get more speed from more rowers, and significantly less speed from untrained, amateur rowers, so your guess is as good as mine.

[Fitz]

Re: Someone's gotta know the answer to this:

 

No matter how fit or well-trained they are, I strongly doubt that any number of rowers is going to get a raft going any faster than 3-5 km/h. A canoe? Sure. A rowboat? No problem. But rafts aren't usually terrifically streamlined.

[keithcurtis]

Re: Someone's gotta know the answer to this:

 

If you're talking about a Huck Finn style raft, there is absolutely no way that they can make 10 MPH. I canoe regularly; 10 MPH is good speed, and that's in a streamlined boat. A kayak, maybe, but rafts suck for speed.

 

Keith "I have trouble even making a log raft that will float" Curtis

[tgrandjean]

Re: Someone's gotta know the answer to this:

 

It depends. Is beer involved?

[Old Man]

Re: Someone's gotta know the answer to this:

 

How long would it take for four adults to row across the Mississippi on a raft?

 

African or European?

[Curufea]

Re: Someone's gotta know the answer to this:

 

It depends. Is beer involved?

Well, they do say American beer is like making love in a canoe

[Outsider]

Re: Someone's gotta know the answer to this:

 

10 mph is way too fast for a log raft.

 

The world record speed for competitive rowing (8 man racing shell) is 2000m in 5 minutes, 19.85 seconds. That works out to 22.51 kph, or 14 mph.

 

I'd go with more like 1 mph...

[Matt Frisbee]

Re: Someone's gotta know the answer to this:

 

Since I live within spitting distance of the aforementioned Father of Waters, here's my take on it:

 

The river where I live is about 0.6 miles from one bank to the other. A couple of years ago, we had a bunch floating a trash raft down the river and were lucky to make 5 mph moving with the current, though they had to stick to the shoreline since the channel was the domain of river barges. Having done some canoeing in my life, I'm thinking 3 mph is fair speed for a raft in calm water.

 

Thus, at 3 mph it takes about 12 minutes to cross the river, presuming it is 0.6 miles wide.

 

Matt "Lives-three-blocks-from-the-shore" Frisbee

[Labrat]

Re: Someone's gotta know the answer to this:

 

Since I live within spitting distance of the aforementioned Father of Waters, here's my take on it:

 

The river where I live is about 0.6 miles from one bank to the other. A couple of years ago, we had a bunch floating a trash raft down the river and were lucky to make 5 mph moving with the current, though they had to stick to the shoreline since the channel was the domain of river barges. Having done some canoeing in my life, I'm thinking 3 mph is fair speed for a raft in calm water.

 

Thus, at 3 mph it takes about 12 minutes to cross the river, presuming it is 0.6 miles wide.

 

Matt "Lives-three-blocks-from-the-shore" Frisbee

 

I think yours is the winner, Matt. I am working with a wider model but now that I have a good mile/minute ratio plus the stats for the Mississippi (thanks AlHazred) I can work it out. This is one of those problems that I would like a more practical answer instead of the math model answer. Triangulation and back-of-the envelope calculations is where I was when I wrote this, I was looking more for experiences and 'real life' modeling.

 

BTW we're talking four inexperienced adults on a 'Huck-Finn' type raft.

 

Thanks everyone! Now the adventurers can get to the other side!

 

[Rep to Matt, AlHazred and Keith (again) Curtis]

[Savinien]

Re: Someone's gotta know the answer to this:

 

How many people are you running through you TA module?

[garou]

Re: Someone's gotta know the answer to this:

 

If you're talking about a Huck Finn style raft, there is absolutely no way that they can make 10 MPH. I canoe regularly; 10 MPH is good speed, and that's in a streamlined boat. A kayak, maybe, but rafts suck for speed.

Oh, you could get a raft going 10 mph. Downriver, with a really strong current, and only for a minute or two before the whole thing flips over or breaks apart, but it could do it.

 

My guess is that, even with 4 adults, a raft is only going to be moving at 2-3 mph at best - a log raft is heavy, and has the aquadynamic properties of a brick. A canoe, kayak or rowboat would all go faster, but a raft is not designed for speed or maneuverability.

[Labrat]

Re: Someone's gotta know the answer to this:

 

How many people are you running through you TA module?

 

Four... Four unlucky fools.

 

I made a statement that it might take 'two hours' to get across by raft but I fear that I was mistaken. Now here's a question for the Mapmaker of the Westerlands: Mr. Curtis, just how wide is the Corwine River? I figgered that it dumps out into a swamp so it can't be too swift of a current, could it? I'm geologically challenged.

[Rapier]

Re: Someone's gotta know the answer to this:

 

I just want to chip in a little here. Keep in mind there are two components to any kind of water movement. Not only will you be flowing with the current (eg in this case, down stream) but also lateral (eg perpendicular to the current).

 

Your parallel current (with current) could easily hit 10 mph in certain spots.

 

Your perpendicular current should never probably go past 2 or 3 mph and I would even lower that for vastly inexperienced rafters...especially if they were stranded, had never done this before and made the raft themselves.

 

Keep in mind that an inexperienced rafter (or even canoer, for that matter) can very easily not understand enough about river currents and spend a few hours being unable to cross the centerpoint of a 100 yard wide river because the current keeps tossing them back to the one side.

 

I would rely heavily on my luck dice and skill rolls. Does the raft stay together or come untied at the first rapid? Are the rowers able to keep the raft afloat and pointed in the right direction? How far down the river do they overshoot their target (I consider it a given that they will not make it across the river where they want to).

 

You could very easily be looking at a harrowing 10 minutes of RP crossing this river!

[Markdoc]

Re: Someone's gotta know the answer to this:

 

Four... Four unlucky fools.

 

I made a statement that it might take 'two hours' to get across by raft but I fear that I was mistaken. Now here's a question for the Mapmaker of the Westerlands: Mr. Curtis, just how wide is the Corwine River? I figgered that it dumps out into a swamp so it can't be too swift of a current, could it? I'm geologically challenged.

 

You can cover your "two hours" *** by pointing out that the river is full of snags and mudbanks, that the bottom is soft and hard poling and so on. I've travelled on a home-made raft (plastic drums rather than logs, but I imagine that logs would be even heavier and less wieldy).*

 

1-2 miles an hour is fine going on a raft, if you are poling and I could easily imagine that going cross-current, dealing with contrary back currents and getting off the inevitable snags, a missisippi-size river could easily take more than an hour to cross. Hell, in real life, it took us 10 minutes of frantic activity to to cross limeburner's creek - a slow river in a mangrove swamp - all of about 80-100 feet across. Poling across anything with a muddy bottom is hell.

 

cheers, Mark

 

*the home-made raft, though slow and unwieldy was an improvement on the corrugated roofing-iron home-made canoe, however, which although it worked, really needed a crew of three - two to paddle and one to bail. We had to abandon the raft however, because we discovered there was no way in hell we could pole it upstream in even a slow river and we were, anyway, too lazy to try and carry it home.