The Upsidedown Boat

My last post took issue with a Mythbusters pirate episode. I thought I might as well comment on their second pirate episode. In this case they tried something from Pirates of the Caribbean, Curse of the Black Pearl.

Early on in the movie, Jack Sparrow and Will Tanner need to get aboard the Interceptor. They do this by turning a rowboat upside down and using this as an improvised diving bell and walking underwater to the ship.

Would this work? Not as shown. The Mythbusters tried this and found that the trapped air in the boat gives it too much buoyancy. It would have floated to the surface. If the pirates carried enough weight to keep them down then they would not have been string enough to hold the boat down.

Myth busted, but there is a flaw there. Normally the Mythbusters figure out how to make a myth work but they didn't try in this case. This seems like a big flaw.

First, the concept of a diving bell was well know by the end of the 17th century. Sometimes an actual bell would be used. An improvised diving bell could be constructed by weighting down a large barrel. There isn't a lot of difference between a barrel and an upsidedown boat so the concept could work. The flaw in the Mythbusters methodology is that they tried weighting down the pirates instead of the boat.

This would be tricky. With a diving bell, you would make it heavy enough to stay down. If it was heavier than it needed to be then you used a block and tackle to suspend the barrel.

Jack and Will would not have that option. They would have to find a balance between heavy enough to stay down and light enough to carry. Further, they could have to use objects at hand. I'm not sure how much iron mongery they would find near the water's edge and they would have to be careful about attracting attention. They would also have to find places on the boat that were strong enough to support the weight and well balanced enough that the boat didn't turn over and let the air out.

So it would be possible but very difficult to pull off. On Mythbusters that usually gets a Plausible rating.