Capsize screening value for the Tartan 4100 is 1.89. 1.89 is under what is normally considered the limit (2.0) that a boat capsize screening value should be at in order to be considered as a safe boat under sailing conditions. The formula to determine the capsize screening value can be expressed in the following manner; C= 4 * (23245)^ -1/3 * (13.5)
A capsize screening value is a relatively modern calculation that was instituted in the 1970's. The value is determined by calculating the stability of the boat. This can be done by using the beam width and the displacement of the boat in order to determine a value. If the value is less than two, then the boat is said to be relatively stable. The calculated value, however, is not a hard and fast number, instead it is guideline. There are a lot of factors that go into determining whether a boat capsizes or not, and a mathematical formula will not change the fact of whether there is ballast in certain areas, or weight being displaced, or any of the numerous other factors that can cause a boat to capsize.
Calculating the displacement volume of the boat is a way of determining how much water volume is displaced by the space taken up by the boat when it is sitting in the water. The reason behind calculating the displacement volume of the boat is to provide the sailor with the knowledge of the boat's float plane. A boat's float plane is the point when the boat allows in water if too much weight is placed in it.
The United States Coast Guard guidelines state that the calculations are to "ascertain a measured cubic capacity of the boat" (USCG, 2014). One method for to measure the displacement is to measure the depth to the breadth, the water line length, and the water line breadth. Displacement if figured by taking the cubic footage of the boat (in this case 35.68) then times that by 62.4 pounds. The displacement volume in pounds for this case is 23,245 and the displacement value is 35.68. The displacement that the Tartan 4100 is safe for ocean sailing would be the 23,245 pounds divided by 7 which would equal 33.7. A less stringent method for measuring the displacement is by figuring the area of the boat, adding the area all together and then times it by two. The result can then be plugged into the following formula: Volume x 62.4 divided by 5 for outboards and by 7 for inboards. The values figured herein are taken from the example given. By no means are these numbers the only considerations to be undertaken when figuring the safety of the boat. If there is additional volume (or volume that is taken up by equipment etc.) on the boat, then that has to be taken into consideration as well. Also, when figuring the overall dimensions of the boat be sure to use the beam calculations for width and length rather than the length and width of the boat itself. The reasoning behind this should be self-evident; if you are using a calculation that incorporate the beam width and length, oftentimes the beam is different than the boat itself.
You’re 100% through this paper. Sign up to read the full paper.
Sign Up Now — Instant Access Already a member? Log inAlways verify citation format against your institution’s current style guide requirements.