C-27 Hull Speed

[jslocum]

What is the hull speed of a C-27. Does it vary fromyear to year, or standard to tall rig?

 

[Paul]

6.2 Kts

According to this site...http://www.geocities.com/Catalina 27/under C27 specs, it's 6.2 kts.The speed is set by the hull length and not the rigging so it doesn't vary throughout the C27 run. The C270 has a slightly higher hull speed as it is longer at the waterlinePaul

 

[Michael McCann]

Hull Speed

A 'close enough' figure can be obtained by multiplying the square root of the water line length by 1.34. For example my C36 has a water line length (DWL) of 30'3" that is 30.25'. The square root of 30.25 is 5.5 times 1.34 = 7.37kts. hull speed. This is the speed at which the bow and stern waves are as far apart as they will get.Mike

 

[Michael McCann]

Hull Speed

I should have done some research first instead of providing an example. From the 'Boats' link on this site, the specs for the C27 are DWL = 21'9", = 21.75' sq/rt = 4.66 X 1.34 = 6.25kts. For the C270 DWL = 23'9" = 23.75' X 1.34 = 6.53kts.Mike

 

[Peter]

What is hull speed?

I agree with Paul that the theoretical hull speed of the C27 is about 6.2 knots. BUT that doesn't take into account the fact that the boat can "squat" and increase the speed it can attain consistently. Further, surfing can make hull speeds irrelevant. I've sailed for 4-5 hours with the loran showing never less than 7.1-7.2 knots with the spinnaker up, and up to 9.2K for brief periods surfing down 8-10 ft rollers from San Francisco to Monterey CA.

 

[MJ]

Boat Heel

You will also go faster when your boat heels; this is due to the water line length increasing. I have gotten mine up over 6.6 kts without really trying too hard.