Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.
The series 40 blocks are rated at 2,800lbs and can accommodate lines up to 5/8", whereas the 30 series blocks, rated at 2,000lbs, can use up to a 1/2" line.
Since boats our size generally have 1/2" mainsheets or less, I would buy the series 30 blocks. (I don't even have docklines that go to 5/8")
BTW, the auction for the series 30 blocks is currently at $80.00 plus $15.00 shipping and handling for a total of $95.00. Garhauer lists these two blocks for $86.52 plus shipping. I would bet that Garhauer's shipping would be less so you might break even (or save a dollar or two) by ordering directly from them.
I use Garhauer for several products (where wieght and quality don't matter), 25 series blocks with shacles mast base plate, genoa cars good genoa cars bad (they hang up lines and bend) I would never use their products for a purchase system. The Harken Airblocks are a major event in block evolution and are the only product I would consider for a new mainsheet or vang system.
Our 1980 Cat 25 came with two mainsheets one of which is a Garhauer, four purchase, 30 series. The other is a Shaeffer, three purchase. The Garhaurer a nice piece of equipment, but the four purchase requires more time to adjust due to the extra line that's associated with it. We find we use the lighter weight three purchase just because it is more responsive and it hasn't felt inadequate for the task. I'd prefer a better quality set-up and will be checking out Frank's suggestion of the Harken airblocks. Frank, you have all the cool stuff!
BTW the four purchase works very slick for raising/lowering the main and we keep it aboard at all times.
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ. The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.