Tuesday, November 18, 2008

The Ralf Relative Rolliness Scale

You have no doubt heard of the Beaufort Scale. This is a gauge of wind force from 0 to 150 knots which is supposed to tell you whether or not you can go sailing today. What you really need to know about wind, however, is that it works like earthquakes with the force growing exponentially. 30 knots is a whole lot more than 20. 40 is seriously nastier than 30 by a considerably greater amount than the 20-30 increment. I think 50 and 60 are like 8 and 9 point quakes on the Richter Scale, something to be avoided at all cost.

The longer we spend on the Pacific, however, the more convinced I am that we cruisers also need a Ralf Rolliness Scale. This 0 to 6 scale would describe the degree of comfort found at an anchorage based on the amount of bounciness. An anchorage can be quite comfortable with little or no swell, or you can bounce around like the rubber ball on the end of child’s paddle toy. Discomfort comes from the wakes of passing boats, ocean swell, wind fetch, tide and current. Just as wind changes on a daily basis, the Ralf Rolliness rating in a given anchorage can change from day to day, even from hour to hour.

Some anchorages, however, consistently suck. I for one would really like the cruising books to be more explicit about the amount of suckage. I’d also like to be able to get on the VHF and say, “Hey everyone, you know that little place next to Wharf #2 in Monterey Bay that’s supposed to be so comfortable even if there is a NW swell? Well, we’re here in a Ralf 4. Do not venture in. We’re abandoning our anchor early this morning.”

Or how about: “This morning we are waiting out a truly heinous low pressure system in San Simeon. This is the most beautiful spot we have anchored since Native Anchorage in Knight Inlet. Fortunately, the bay provides reasonably good shelter from the prevailing (and in this case storm driven) north westerly. There is a mild Ralf 1 swell from the south, shading to Ralf 2 when the breeze pushes us beam on to the swell.”

See how useful that would be? Let me take a first stab at formalizing the Ralf Rolliness Scale:
Rolliness Scale

1 comment:

Frank said...

Oooooh, I like the idea of assigning an anchorage a Ralph value. I'm gonna adopt your scale and have it live right next to my Beaufort sheet.