Performance

I had got the impression from reading a number of forums and listening to the “club bar expert” that Moodys were on the slow side. I happened to say that to Dennis (A yacht broker and owner of a Moody 44 – SV Caribbean Soul) and this is his reply…

“I find the boat to be quite fast, actually, though certainly not a racer, but then that’s not its design. In the US there is a rating system which handicaps all boats and allows them to compete against each other, as opposed to having one design. It is called the Performance Handicap Racing Formula (PHRF) and assigns a number to every boat related to its speed over a mile’s course. The M-44 has a 106 handicap and that is considered pretty fast. Typically, 100 is scratch and anything close to that is fast. The really fast trimarans will have a number far below 100, such as a Corsair 31 (which will sail the windspeed) which has a PHRF of about 20. My last boat, a Bruce Roberts 38 Ketch, had PHRF of 178….”

1. Displacement / Length Ratio (D/L) The result of this calculation is a general guide to overall performance level, load capacity and relative comfort at sea. The manufacturer’s web site will sometimes base this figure on something less than typical loaded displacement – you have to be quite ruthless in estimating your real weight when extended cruising or even on that blue water adventure! This uses LWL for its calculation but LOA can matter too. When a boat is heeled the LWL may increase changing this value significantly. Here is what Ted Brewer says…”STORM, a wonderful 27′ LWL sloop on which I raced with Bill Luders many years ago, had a D/L ratio of 386 so she would be considered very heavy by today’s standards. However STORM was 39′ LOA and when she heeled to a breeze her long ends would increase her sailing LWL, thus reducing her D/L ratio to a more reasonable figure when we were beating to windward. If she picked up 3 feet of WL her D/L ratio dropped to about 281, a significant change, and one that made her a very competitive racer in the 1960s”… D/L range of typical values:

  • 40 to 50 Light racing multihull
  • 60 to 100 Ultra light ocean racer
  • 100 to 150 Very light ocean racer
  • 150 to 200 Light cruiser/racer
  • 200 to 250 Light cruiser
  • 250 to 300 ** Average cruiser (Optimal)
  • 300 to 350 Heavy cruiser
  • 350 to 400 Very heavy cruiser

2. Sail Area / Displacement Ratio (SA/D) As with the D/L ratio, the displacement figure used must reflect the real-world weight of the boat in the water. The hardest number to get is the correct sail area figure – it depends on the sail plan, and the sea conditions. Total area has traditionally been considered to be the sum of the foretriangle, plus the triangular area of the main, roach not included. Because of the highly roached mains found on many of the newer boats, it’s becoming common to quote the full area of the main. SA/D range of typical values:

  • 16 to 18 ** Heavy offshore cruiser (Optimal)
  • 18 to 22 ** Medium cruiser (Optimal)
  • 22 to 26 Inshore cruisers, racing boats
  • 26 to 30+ Extreme racing boats

3. Capsize Screening Formula (CSF) The technical committee of the Cruising Club of America came up with a simple formula to determine if a boat had blue water capability. The CSF compares beam with displacement since excess beam contributes to capsize and heavy displacement reduces capsize vulnerability.

The formula is the maximum beam divided by the cube root of the displacement in cubic feet; B/Displ.333. The displacement in cubic feet can be found by dividing the displacement in pounds by 64, of course.The boat is acceptable if the result of the calculation is 2.0 or less but, of course, the lower the better.

For example, a 12 meter yacht of 60,000 lbs displacement and 12 foot beam will have a CSF Number of 1.23, so would be considered very safe from capsize.

A contemporary light displacement yacht, such as a Beneteau 311 (7716 lbs, 10’7″ beam) has a CSF number of 2.14. Based on the formula, while a fine coastal cruiser, such a yacht may not be the best choice for ocean passages.

What’s puzzling is that a yacht like the Tartan 4100 (CSF 2.02) and the Sabre 402 (CSF 2.01), both of which have pretty well documented track records as a blue water cruisers should have a CSF of over 2.0 – indicating that they fail the test described here…they are quite beamy for their weight…I guess.

There is a good review of the Moody 44 here…