CD30MKII-How fast?

[Richard Feffer]

I have only had "Adamarie" for a short time. Yesterday, in a delightful breeze, my knotmeter indicated over SEVEN KNOTS on several occasions. They were brief moments, but it did indicate six plus for much of the time. Wind was brisk, but seas were not enough to slow the boat down. I didn't think my boat was capable of making that speed. How about it CD30 and CD30MKII owners? What is your best speed under similar conditions?



RichFef@Prodigy.net

[Larry Austin]

Hello Richard, sounds like you're really enjoying your new Cape Dory.
About 3 weeks ago the wind was from the north at about 18 -22 out on the sound and I hit 7 knotts a couple of times that afternoon. My speed is normally 5.5 to 6.5 in those winds but this day
the sound was relatively flat for the amount of wind. I had my 130 jib all the way out.
Good question, I'd like to hear from others as well.

Cheers.
Larry Austin
CD 30 MKII
LAYLA



laustin@us.ibm.com

[Richard]

Hi Larry,
Likewise on the 5.5 to 6.5. I didn't think she would do 7! I thought my speed log was out of adjustment. I wonder what the hull speed is on the MKII?

Hello Richard, sounds like you're really enjoying your new Cape Dory.
About 3 weeks ago the wind was from the north at about 18 -22 out on the sound and I hit 7 knotts a couple of times that afternoon. My speed is normally 5.5 to 6.5 in those winds but this day
the sound was relatively flat for the amount of wind. I had my 130 jib all the way out.
Good question, I'd like to hear from others as well.

Cheers.
Larry Austin
CD 30 MKII
LAYLA

RichFef@Prodigy.net

[John]

Hi Larry,
Likewise on the 5.5 to 6.5. I didn't think she would do 7! I thought my speed log was out of adjustment. I wonder what the hull speed is on the MKII?

Hello Richard, sounds like you're really enjoying your new Cape Dory.
About 3 weeks ago the wind was from the north at about 18 -22 out on the sound and I hit 7 knotts a couple of times that afternoon. My speed is normally 5.5 to 6.5 in those winds but this day
the sound was relatively flat for the amount of wind. I had my 130 jib all the way out.
Good question, I'd like to hear from others as well.

Cheers.
Larry Austin
CD 30 MKII
LAYLA

Some interesting discussion here. I can honestly say I've never been better than right around 6 knots. That generally falls right in line with the boats theoretical hull speed of 6.28 kts. maximum. That max hull speed is based on the hull speed formula of: 1.34 x square root of LWL.

I don't know how reliable knot meters are from one to another or even one on its own. Turbulence, fouling etc., can all have an effect. Maybe GPS would be a better measuring device. I'd be curious to hear from others with CD30's to see what speeds they are experiencing. The CD30 cutter PHRF rating is 207.

[Harvey Wilson]

Hi Richard...

I don't think the GPS will give an accurate reading at the speeds of most sailboats, because of SA...this is where Uncle deliberately screws up the signal....it may be close if you have the differential module.

My garmin 12XL works great in the car, but while sailing, I regularly get 4-6 knots in a 17 footer!!

Harvey/ Ga

s/v Stargazer



harveywilson@compuserve.com

[Patrick Turner]

GPS will give you speed over ground wich is good to know but may be confusing if your trying to determine speed through the water. If your bucking a tide, your knotmeter may register 6 knots but you may actually be only traveling 3 knots over the ground surface.

My CD 30 cutter us usually right around the 5.5 to 6.5, sometimes pushing up against 7.



patturner@earthlink.net

[Harris]

From my readings about Alberg and other "50's style" keelboats....many of the narrow wineglass shaped boats like the Triton and my Sea Sprite 23 were designed for favorable ratings under the CCA rules (Cruising Club of America). this formula gave benefit to a short waterline. The end result is long overhangs and boats that initially heel easily to 30 degrees and then dig in(lengthening the heeled waterline). Most people on this board already know this but the concept facinated me when I first read about it. My boat is 22.5 feet with a 16.25 waterline. Pretty extreme example. Heeled I get a 19-20 foot plus possibly including a bow and stern wave riding up the hull. My freind brought a GPS aboard this weekend and in flat non tidal water on a beam reach with Genoa and main we were doing 6.3 in 10 knots of wind. Subject to debate. Take 20 square times 1.34 and it equals.....5.99. pretty close. For arguements sake say the 32 heeled to the optimum angle is a 30 foot waterline. that gives 7.34. Not as slow as you thought.......eh?



hg@myhost.com

[Boyd Bundy]

I have a CD30 MkII and my DataMarine Knot meter reads over 10 knots for brief periods when sailing in 20 knot winds with the 150 or working jib hoisted and the rail almost in the water. I think the Knot meter is completely bogus. I wish I knew how to calibrate the stupid thing. The GPS reports 6.5 knots max speed at any time for this boat with long term averages at 5.5 to 6 kt. If anyone knows how to calibrate a knot meter please let me know.



wbta@pstcomputers.com