[Rhodes22-list] boat speed to outrun storms

[J Cook]

 I picked this off our local sailing club's newletter:



Friends:

One of the justifications that folks who hawk larger boats frequently cite is that a few more feet of waterline will get you the extra boat speed necessary to outrun or dodge bad weather.

To refresh your memory, the maximum theoretical hull speed of a displacement boat, such as a cruising sailboat, is the square root of the water line length (in feet) times the constant 1.34.  This gives the fastest speed the boat is capable of (in non-surfing or non-planing conditions) and is expressed in knots.

So, my boat with its 30 foot waterline is capable of 7.34 knots.  I thought it would interesting to see how much longer the boat would have to be to out-run Tropical Storm Wilma if I was so unlucky as to be in her path in the Atlantic today.

>From the National Hurricane Center
WILMA IS MOVING TOWARD THE NORTHEAST NEAR 53 MPH

Based on this rapid forward motion, the waterline on a boat that would be capable of outrunning this storm would be:

(53 mph x 1.16 knots/mph / 1.34) squared = 2105 feet.


Now, even with the most understanding Admiral in the fleet (my first mate), I just can't see her agreeing to buy boat this long just to outrun a storm.

Thank you Wilma, for allowing us boaters in North Central Florida to dodge yet another bullet, but we don't appreciate you picking on all the boaters in South Florida just because their yachts weren't long enough to out-run you.