Is there any conceivable way one could use a bathtub as a boat?
March 29, 2004 1:19 PM   Subscribe

Is there any conceivable way one could use a bathtub as a boat? Have you heard of anyone doing it? Would it even float? I found the site for the annual Yukon River Bathtub Race, but the boats in their galleries are more like regular boats that just happen to have bathtubs mounted on them.
posted by edlundart to Science & Nature (11 answers total)
Are you thinking about the bathtubs you see installed today or the kind that fit the discription "tub".

Here is your answer. I've seen better tho.
posted by thomcatspike at 1:25 PM on March 29, 2004

Sheesh, looking at the gallery seems these are professional tub boat builders. Must be a lot at stake than bragging rights.
posted by thomcatspike at 1:28 PM on March 29, 2004

Response by poster: i'm open for both alternatives but ideally i'm thinking of the old-fashioned ones. i have more faith in the possibility of the new ones floating though. the picture you found is promising (though it looks like they're about to sink), but i'm unable to find the context for it. i did find another tub race page (scroll down) though, with boats that are a lot less tricked-out than the yukon river ones. the site for this race is supposedly but that doesn't work for me...
posted by edlundart at 2:02 PM on March 29, 2004

The bathtub racers started out as actual baths with a few additions to create some sort of hull to allow them to plane and have evolved into the craft that you see on the Yukon River Bathtub Race in the link above. Modern bathtub race boats are actually race hulls with a lightweight replica bathtub made from fibreglass mounted on/in them and bear no relationship to an actual bathtub apart from a passing resemblance (if you look hard). The sport has died off a great deal over the years, but in the '80s was a very serious (if somewhat fringe) sport with huge sums of money being spent and no, thomcatspike, there was never much more than bragging rights up for grabs.

Without some sort of stabilising device, a real bathtub will never be successful as a boat, as the weight is too high and they are too narrow to float without assistance. With an outrigger for balance, a bathtub could be made to float maybe one person and a paddle, but that is about as far as you could take it.

elundart, what is it you actually want to do? With more information, you might get an actual answer.
posted by dg at 2:12 PM on March 29, 2004

Response by poster: dg, yours is very much an actual answer -- thanks for the information. i don't want to do anything in particular, i'm asking out of curiosity. somehow the idea came to my mind and i was wondering if it was possible.
posted by edlundart at 2:24 PM on March 29, 2004

When I was an adolescent, we found an intact bathtub "shell" (?) at a junkyard. It looked like molded, heavy duty fiberglass--completely smooth on the inside, and rough on the underside. The shell itself was probably a little less than 1cm thick.

We formed a club where membership was limited to those who would take the bathtub across a nearby lake and back. A harrowing 45 minute ride with a Hills Bros. coffee can to bail out the water we took on. It was unstable, and crept along at a snail's pace.

Drunkenly tried to replicate the experience as an adult, and promptly sank the bathtub.
posted by cadastral at 2:25 PM on March 29, 2004

You asked for it. Let's take this tub as an example.

It has reported dimensions of 68-7/8" L x 31-1/2" W. Not counting the legs, I'd say the height is about equal to the width. If it were perfectly rectangular then, it would occupy volume 68341in^3. Since it's a rounded tub, let's say it actually occupies 80% of that, or 54672in^3.

If the tub were submerged up to the brim, it would displace this volume of water. The density of water is 1000kg/m^3, so it weighs 9800N/m^3 or 3.612×10^-2lb/in^3. Therefore the weight of the water displaced is (54672in^3) * (3.612x10^-2lb/in^3) = 1974.7lb. This is much larger than the 340 lb weight of the tub (plus the weight of a passenger), so by Archimedes' Principle, it will easily float. In fact, it will probably be less than halfway submerged.

Then again, it has a rounded bottom and looks rather top-heavy, so it will tend to capsize very easily if you don't stabilize it with outriggers or something.
posted by Galvatron at 2:30 PM on March 29, 2004

There's a world famous bath tub race here every summer (from Vancouver Island to Vancouver). So yes, you could.
posted by The God Complex at 2:30 PM on March 29, 2004

Response by poster: cadastral, that's a great story, i was hoping to hear someone's personal experience with this! amazing -- and Galvatron, you rock. thanks!
posted by edlundart at 2:39 PM on March 29, 2004

I was dubious, but I guess it's a popular thing to do! (I was thinking of cast iron tubs. These seemed to have a bit too high of a weight/displacement ratio to me. I guess not).

You can also brew beer in a bathtub (from a previous AskMeta thread on homebrewing).
posted by troutfishing at 2:52 PM on March 29, 2004

posted by The God Complex at 2:54 PM on March 29, 2004

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