Quote:
Originally Posted by sailaway21
I have not played around with it John but I'd hazard a guess it is because immersed hull is a far more important variable then the keel depth below the water, or draft.
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Sailaway, I find that proposition intriguing, and counterintuitive. If your suggestion is correct, that might explain why the LPS/AVS for the Catalina 42, and other similar relatively flat-bottomed modern designs, is so low.
But, with that in mind and looking at some photos of JeffH's boat hauled out (that he has posted in the photo gallery), I am surprised his LPS number came out as high as it did. The hull form of his boat seems to emphasize low wetted surface -- very different from our boat. Our boat is more old school -- the hull is down deep IN the water, rather than floating atop it like the wider, flatter modern designs. [This is not intended as a criticism of Jeff's boat, just an observation.]
Quote:
Originally Posted by jrd22
JohnR- I couldn't find a hull draft for our boat either. Using the actual design drawings I was able to measure fairly accurately the hull draft. I came up with SSV of 26.73 and AVS of 133.9. I am going to call Ted Brewer and ask if he has the actual values tomorrow. This is for a Brewer 40 PH.
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JRD, that's interesting. I have some drawings too of our boat, but it's somewhat of a guess as to where the hull ends and the keel begins. Viewed in athwartship cross section, ours has the fairly traditional wine glass profile, so the transition from hull to keel is very gradual. And the ballast is bolted externally to a fairly deep keel stub. So I am left wondering where US Sailing gets that value? From the owners? If so, there could be a large fudge factor on some boats.
I'll be curious to hear Mr. Brewer's thoughts. Maybe you could direct him to this thread and see if he might be willing to post some comments? If not, I look forward to hearing from you what you learn.
In the meanwhile, I'm going to run the numbers on our boat again, then I will post the figures and how they were derived. Maybe others would be willing to do the same with their own boats and perhaps the comparisons will make for interesting discussion...