[GeorgeB]

Running the Numbers

I took the opportunity to run the numbers and this is what I get:

DSP to Length = 368 (200-300 is "cruising")

<O
Sail Area to DSP Ratio = 14.2 (Most boats are between 16-18)
<O
Hull Speed = 6.05 kts

<OVelocity Ratio = 1.05 (under powered is less than 1)

LOA to Beam = 2.72 ("fine" is 3.5-4)

Capsize Risk = 1.99 (over 2 cannot compete in ocean races)

Comfort Ratio = 22.09 (This is in the range of racers, cruisers are 60+)<O

The LOA/Beam ratio indicated a little "tubbiness", but probably is this way to accommodate an interior. To get a "fine" hull, you would need to decrease beam by a foot or more which would probably "loose" the cabin. Where you are getting killed is the relatively small rig (small sail area) in relationship to the displacement. This is going to be a slow boat. The capsize risk and comfort ratios are marginal again, due to the high DSP to length ratio and smaller hull form (length and DSP). So how did I do? What boat is this? A Pacific Seacraft?

<OValiente, can you give me your racing boat's data for comparison?

 

[GeorgeB]

You know, in keeping the name secret, the boat is either going to be something really good or really bad. The relatively small rig had me going the Crealock direction with the Danna, but I just had a thought – could it be a Catalina 27? The beam made it too wide to be a trailer sailer. Either or, the design problem here is stuffing a large enough cabin to have a head, sink, stove, and sleeping for four and still be around 27’. Something has to give. I do not think there is a true “cruiser-racer” out there in that size range. To get the performance that the ratios suggest, a boat that small needs to be more of a day sailor. Think the comparison of say, a J24 and a Catalina 25. That is why I am curious about Valiente’s dimensional data. I want to run the numbers of a racer.

 

[GeorgeB]

Just ran the numbers for a Catalina 27 and they do not fit. Try again. Any other suggestions?

 

[GeorgeB]

Kwalter – Just to check, do you have the dimensional data correct? To “build” you a hotter boat, I need to shave a foot off of the beam, trim out a thousand pounds, and increase the sail area by 75 sf. I don’t know what it would look like, but the ratios would like it. But seriously, the design problem here is “cramming” in that cabin to make a cruiser in 27 feet. Anything in that design parameter is goining to run into the same problems, number wise. If you’d like, send me the dimensional data of some “comp” boats and we will run the comparisons which will give you a better indication. Give me the PHRF and I can tell you your Pacific Cup rating. Unfortunately, I have a bug in my stability formulas so I can’t tell you your offshore ratings.

 

[GeorgeB]

Here are your numbers Minsy. O.K., now tell me what “ARE” stands for. Also, you will have to eventually tell me what your boat is (so I can update my database). Length is increased in the “middle” of a boat (not the ends) so it takes a certain amount of LOA before a boat grows into its ratios. Congratulations Minsy, it’s a cruiser! (your moment of inertia is the classic number for cruisers)

DSP to Length = 232.1 (200-300 is “cruising”)
<OSail Area to DSP Ratio = 16.6 (Most boats are between 16-18)
<OHull Speed = 7.88 kts
<OVelocity Ratio = 1.07 (under powered is less than 1)
<OLOA to Beam = 3.28 (“fine” is 3.5-4)
<OCapsize Risk = 1.77 (over 2 cannot compete in ocean races)
<OComfort Ratio = 30.48 (cruisers are 60+)

<OScottyT, your Hunter numbers aren’t bad either albeit, you do suffer a little from the “under 30’ syndrome”. Your numbers are almost a scaled down version of my 34. I’m assuming that this is one of those Chernubli (sp) Hunters? Do you race, and if so, how well do you do?

<OOnce again, this is not a Catalina of any stripe (I’ve checked). Nor do I think it is a Com-Pac on the account of the beam dimension.<O