Can anyone help me to find the LWL. load waterline length of my Cat 30; 1988 standard Rig. I am trying to figure the hull speed. Thank you.
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Another Association Suggestion
Barb When looking for information of that type, either go to www.catalinayachts.com or the C30 association, which is either www.c30.org, or www.catalina30.org or net or com. It's out there somehwere
And try the link to a question like yours earlier today. Good luck. Stu
Barb When looking for information of that type, either go to www.catalinayachts.com or the C30 association, which is either www.c30.org, or www.catalina30.org or net or com. It's out there somehwere
And try the link to a question like yours earlier today. Good luck. StuFrom the home page, boat info menu, select model information. select boat from menu on left, then select specifications. A standard 30 has an lwl of 25ft.
Barb, LWL is the length of you boat at the Waterline. I believe the Cat 30 is 25'-0". Froude's Law Froude's Law states that a displacement hulled boat will go faster than the wave length created by the hull as it moves through the water. This wave length is equal to 1.34 x LWL. In other words, a boat with a 25-foot waterline length will go no faster than 6.7 knots. Most boats can be overpowered or may sail down the back of a wave and temporarily exceed this calculated maximum, but they cannot maintain that speed unless they have a low displacement/length ratio when they plane.
Hull Speed
Paul, I think your formula should read 1.34 times the square root of the LWL. The C30, with a LWL of 25, has a hull speed of 6.7, not 33.5 as your formula would suggest.
Paul, I think your formula should read 1.34 times the square root of the LWL. The C30, with a LWL of 25, has a hull speed of 6.7, not 33.5 as your formula would suggest.
Remember its Theoretical
I have a Cat 30 and I can routinely hold 7-7.5knots verified by knot log and GPS with about 15knots of wind. The max hull speed is theoretical and can be surpassed. I've even walked away from Hunter 33's in similar conditions
I have a Cat 30 and I can routinely hold 7-7.5knots verified by knot log and GPS with about 15knots of wind. The max hull speed is theoretical and can be surpassed. I've even walked away from Hunter 33's in similar conditions
Static vs. Dynamic
Also remember the before mentioned 6.7 knots was calculated using the static vs. dynamic LWL. When the boat heels, the LWL increases by virtue of the overhangs thus providing a greater speed. The hull speed can not be surpassed unless the bow wave is able to be over run. This is called planing.
Also remember the before mentioned 6.7 knots was calculated using the static vs. dynamic LWL. When the boat heels, the LWL increases by virtue of the overhangs thus providing a greater speed. The hull speed can not be surpassed unless the bow wave is able to be over run. This is called planing.
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