How easily driven is a particular hull? - Page 2 - SailNet Community
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post #11 of 14 Old 07-21-2011
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The Cal 29 has a 24' LWL and is really stable

The J24 has a 20' LWL not so much in the stable

The A4 motor is mounted at or near the max 15 degree angle BUT the outboard was level and the Cal still had stern squat were as the J24 had littel if any stern squat at the same speed

It just seems to be the nature of pushing that style hull VS the C/E from the sails being more or less in the center of the boat and if it squats under sail it does it level

The question is how much HP does a 400 to 500 SQFT sailplan make in twenty knots of wind as it takes some honking wind to break 7 knots on the Cal

The Cal will go above 6 knots under power BUT the water gets really deep in the cockpit and its NO fun standing in 12" of water and using 3 times as much fuel to go 1 knot faster

The Cal was built with and still has its ordinal 12 x 8 prop which is a bit big BUT does not seem to have hurt the motor as it still is within spec at 41 years

1970 Cal 29 Sea Fever

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1981 J24 Tangent 2930
Tommays
Northport NY


If a dirty bottom slows you down what do you think it does to your boat
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Last edited by tommays; 07-21-2011 at 03:45 PM.
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post #12 of 14 Old 07-21-2011
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Theoretical hull speed = (Sqrt of LWL)*1.34. You can reach that speed with a reasonable amount of energy (sail or mechanical) but to exceed that you have to have a lot more power. The exception is a planing boat or when you get lucky and can use following seas and surf down the faces (thats fun). Again that is theorectical hull speed and can be affected by any of the variables mentioned above, but every non planing boat has a definate point that it reaches this transition.
DD

Doug
Jboat J/37c (new to me Jan 2011); J/22 #1003


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post #13 of 14 Old 07-21-2011
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Quote:
Originally Posted by davidpm View Post
Would you mind mentioning a boat or three that pop into your mind in the 28 - 33' or so size.

Long waterline for lengh:
Fair lines:
Rule induced bumps:
Narrower vs. fatter.

I know you have been doing this a long time and I would like to look up some specific boats and see the difference.

It seemed to me that the Catalina 27 is a little better hull shape than the Catalina 30 according to this criteria, yes?
Just for fun, compare a Farr/Mumm 30 One Design to a Catalina 30.
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post #14 of 14 Old 07-21-2011 Thread Starter
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Quote:
Originally Posted by puddinlegs View Post
Just for fun, compare a Farr/Mumm 30 One Design to a Catalina 30.
That's not fun it's just cruel.
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