AboutKeith Patton Expertise I can answer questions regarding fresh and salt water Catamarran Sailing, techniques and equipment. I can also answer questions regarding the repair of decks and the updating and installation of running and standing rigging on mono-hulls
Experience I have sailed catammarans in fresh and salt water for over 16 years.
I currently own and sail a 30 ft monohull out of Kemah on Galveston Bay, on which I carried out a complete refit.
Expert: Keith Patton Date: 10/10/2007 Subject: eightenth century three masted ship: bark, brig or schooner or
Question QUESTION: I don't know if you will know the answer to my question, but if you don't I hope you might know to whom I can ask the question. I would like to know the approximate speed of a three masted 18th century ship like a bark, brig or schooner. I know it depends on winds, currents etc.
ANSWER: Probably no more than 7 knots. Speed of a displacement boat is governed by a formula. SQRT(LWL) * 1.34 = hull speed. Where LWL is the length of the boat. A sailing ship has to push the water aside to move forward. People are puzzled by the fact that when they put a big outboard on a sailboat they can't get it to go past this empirical number. It is because the boat is falling back into the void made by its own passing. That is why a speed boat rears up; that is until it begins to plane. A sailboat with a keel or a large displacement boat will never plane so it is captive to the formula. Certain instances it will sail faster but it is actually surfing on fast moving waves.
---------- FOLLOW-UP ----------
QUESTION: Thank you for your thorough answer, Mr. Patton. I'm writing an historical novel that involves shipping in the 18th century and will mention you as a source if it is published.
One more question: do you have any idea how much it cost per ton to build an 18th century ship, brig or schooner?
Thanks again.
Answer I found a statement in the source below stating that an average 40 gun ship in 1700 cost 6,080 Pounds Sterling.
A brig it states would carry 16 guns. So one could probably assume that a brig would cost half or a bit less due to the reduced rigging (two masts vs three) than the 40 gun ship.
