Thursday, July 16, 2009

This just in - Cannonballs can sink a ship!

A cannonball was found wedged into the keel of a ship that was sunk during the Napoleonic wars. The big question was if the cannonball could actually pierce the ship's extra thick oak hull? The University of Haifa in Israel answered that question using scale models. The answer is yes, even at low velocities a cannonball can pierce a thick oak hull.

This part is interesting:
The lower the velocity, the more energy was absorbed in causing damage to the hull, and the more the wood splintered, which would have caused more harm to the ship's personnel. The results of this experiment, Kahanov said, are of much significance to the study of the vessel and to the study of naval battles in this period.
Remember the Mythbusters Pirate Special (they just reran it last weekend)? One myth they investigated was the danger of splinters. They decided that splinters were not all that dangerous. This experiment shows the flaw in the Mythbusters' experiment. They used a real cannon but they had it at close range. The ball cleanly pierced the hull, doing even less damage than their air cannon. If they had moved the cannon back a few hundred yards they would have gotten a different result.

Monday, July 13, 2009

Sailing the Whitehall

We took the boat (now named "Firefly") out sailing today. This was our second time sailing (plus a third time at Saint Mary's City with the boat overloaded). The wind was from the West and the lake runs North and South so we sailed up and down it a few times. Combining this with our experiences the first time we took it out on that lake I can say a few things about sailing the Whitehall.

First - when the wind is right it goes like a bat out of hell. We were overtaking the modern sailboats. At one point I was hoping to literally sail rings around one (or at least pass it, tack and pass it again) but the wind died and out boats separated.

It tacks poorly. Whitehalls are designed to go in a straight line. It overcomes this while under sail but during a tack you are sort of coasting, using forward momentum to carry you through the turn (for landlubbers, tacking is making a turn while sailing into the wind so that the wind is on the other side of the boat).

The alternative is to jibe. This is the same as tacking except the wind is coming from behind. This works fairly well although the boom swings rather sharply and I have to be ready with the tiller for when the wind catches it. We did this several times and it worked fine. I was just reading up on jibing and I see that it is recommended that the centerboard be raised for this maneuver. The boat tips as the wind catches it from the other side and that would help since the boat could be pushed sideways instead of tipping.

Firefly had been out of the water for three weeks in dry weather and it showed. A lot of water leaked through the seams. Pumping it out let me more tired than rowing would have.

Wednesday, July 1, 2009


After arguing with someone last Saturday about pirates wearing eyepatches to see in dark holds, I did some more research. I cannot find any period references to pirates wearing eyepatches. The earliest picture I could find with a pirate with an eyepatch and/or pegleg is this one from Howard Pyle from 1892.

Pyle is not the best source. He is known to have made up details such as walking the plank. A few years later this detail was included in Peter Pan and forever associated with pirates.

This is the biggest flaw in the eyepatch myth - first you have to prove that eyepatches were associated with pirates before the late-19th century and it has to come from a reputable source.