I see your point of the weather forcasters saying that they are only saying the ave. BUT, it would have been nice, and hopefully this is occuring with the more recent Syd/hobarts, in that the forecaster can say, this is the best guess, BUT, it does appear that IF this low over here could and might do this and that, then all hell will break lose, so really watch the forecast when you all hit this point, and THEN decide if you want to chance the crossing at Bass Straight! Or the, if this and that do not occur, you have 20-30 knot easterlys, and fun all the way to hobart! otherwise, you may have......
Some of Jeffs comments are what I was thinking about while at the vet with our 4 month old puppy. Tankage, while some say you need more for this type of cruising, or less that that. One needs to look at this from "WHOM" you are. A couple, less water tankage may be needed for a 2 week crossing somewhere, where as the folks I mentioned earlier that went to Oz, a couple and twin 12-14 yr old daughters during the cruise, need more water tankage for those 2 weeks!
A person cruising in the winter here in Puget Sound, will want more diesel or LP than in the summer months here or say in Florida all year depending upon how the cabin is heated.
Water/air drafts if you will, again, depend upon where you are cruising. I can see how George ended up with the tayana he did for where he is at. On the other hand, for where I am, and wanting a 52' boat to cruise in, an older Santa Cruz 52 would be a hoot! BUT, I do not have the water/air draft issues he has doing the eastern canal up and down the coast with bridges and channels etc. Hence why we would choose such different boats cruising.
I also do not like the use of the comfort or roll ratios. One boat I like, the Jeanneau Sunfast 3200, a boat designed for single/double handed offshore racing, has a comfort or roll factor of 2.4. Above the 2.0 or less that is considered good. Yet from what I understand, like its bigger brethren the open 60/70 boats, it will roll back upright quicker etc, than boats with factors less than 2.0, because of the requirements that they right themselves in a certain time frame. ALL of the open 60/70 boats IIRC are purposely put int he water upside down and made to roll upright, and timed while at it. Note here, I may be off on my wording, but for discussion purposes, I believe I am somewhat correct, but maybe off in the final micro details of how these boats are ment to right, timing etc.
Like Jeff mentions, some boats of certain time frames, should probably NOT be taken off shore or equal. Others like the Morris m52, while it may have the EU A cert, I really doubt that that boat was or has any design basis to go offshore. It might only have the B cert for all I know! Which in reality what it is designed to be. So my earlier comment "most" boats over 40' will go off shore is correct. Also, the most recent ARC around teh world cruise, IIRC, a Jeannea 54? was the most popular boat, ie in quantity of the 20 or so boats on that 18 month trek. The actual ARC, Jeanneau and Beneateau have the highest % of boats also. Now some of this should be expected, in that those two build probably MORE boats then the next 8-10 builders combined....... but it still shows that these boats that most would consider to be coastalish in nature have the ability to go offshore and will survive.
Two yrs ago, a mid 80's Jeanneau Sunrise 34 did a nonstop solo driver circumnavigation, obviously with a trip around the main lower capes. So boat with sound design and build, will do what you ask, and then some.
Sorry I am harping Jeaneau to a degree, but I do own one, and like many folks with ownership in brand X if you will, learn what they can about brand X, and brag or compare accordingly. No different than CD with Catalina's! Or Jeff and Farr design boats........
She drives me boat,
I drives me dinghy!