I have just signed on to the trawler list and have read with great interest the discussions held approximately 9 months ago on anchoring. I seem to be studying the same questions only from a different perspective. On the West coast we rarely get hurricane force winds or bottoms material as weak as those you have experienced. My concern hasnt been so much about holding the boat in the worst possible bottom under hurricane winds, but balancing the normal winds and bottom conditions. For example major boat supply houses recommend for my boat a 45 pound anchor. However, I have found that I can anchor my 44 ft. Cutter successfully well over 80 percent of the time on a 12 lb. anchor. Now to those guys who step on buttons to get their anchors up thats no problem, but for the few who still use muscle, jerking up twelve pounds compared with 45 makes a big difference. Some of the results of this work might be of interest. Let us begin by talking about Org, (also, Bamford, West, Marchaj, and Van Dorn who also tackled this subject) and Gerr. Knowledgeable fellows, but just how accurate are there equations in the real world, and in turn the numbers given in the tables found in anchoring 201 and other places. First of all as you know, the equations of Org et al are based on the classic drag equation. As such, they calculate essentially a static load which does not take into account wave and surge loads. Dynamic loads are truly difficult to calculate accurately, and can get extremely high especially for boats with all chain rode. But that is another subject and we will confine this discussion to static wind, and engine loads. Lets start with classic drag equation. The problem stems from the two innocuous coefficients use in this equation, and referred to in anchor 201 as drag coefficient (Cd) and the area (S). Both of these numbers are not easy to get with any accuracy. Where as Org suggest Cd between 0.7 and 1.0 considerable artistic licenses was used to make that recommendation. I have found values in the literature for Cd anywhere from 0.06 to 1.9. Further, calculating the exact area exposed to the wind on a recreational boats is a daunting task (lifelines, dingys, brother-in-law fishing on the bow). However, the accuracy of the load is directly dependent on the accuracy of this area. I am not sure how area of the boat is calculated in Anchor 201. For example, do sailboats calculate the area of the rigging? On the other hand it is not to difficult to measure these values in the field. This I and others (most notable Robert Smith) have done. If we compare these measurements with the various equations and tables we find the AYBC (put together by Org) overstates the loads on the anchor lines by greater than 550%. The accuracy of Org, Bamford et al, has a lot to do with how the area is calculated. For example the calculations given in Bamfords book, over estimate the load on the anchor by about 400%. Better, but still not good because it means if you calculate a wind load of 1000 pounds on your boat you will really only experience 250 pounds during the storm. In order for me to estimate the accuracy of the tables in 201, I need to know how the area in the tables is calculated so I can make similar calculation on my test boats. Of course it is possible for anyone to get a rough idea by comparing the their load results to AYBC, if their results are similar the error is similar. As for Gerr equations, and the tables in 201, comparing these data with ours, is a little more difficult. Most of our tests were run using a feathering prop which has better efficiency in reverse than a fixed prop. Depending on the assumptions, my tests show this equation over estimates the engine load on the rode somewhere between 105 to 150 percent. In this case good is bad. If the engine load is used to calculate a equivalent wind velocity, the errors offset. The closer the Gerr equation is to actual, the worse the combined effect of both errors. Combining the two errors it means that the wind velocity is over by about 65 to 95%. So if you are trying to find an anchor that will hold in 70 knots of wind, you could in fact be actually be searching for one that will hold in 115 to 135 knots of wind. By the way all of this assumes no dynamic (wave) loads, and no current load. A 3 knot current can put considerable loads on an anchor line (on my boat the load is equivalent to 30 knots of wind) did I miss the discussion of current loads? In defense of the AYBC tables, they are overstated to take into account such things as dynamic and current loads, and poor anchoring technique. Don Dodds