My own experience with this family of block has been to think it’s great. ?It might be bigger than you need, except that to run a comfortable-size mainsheet (half-inch, in my opinion), you might not want a block much smaller. ?This one should certainly be able to handle the load; it’s listed as recommended for the much bigger Flying Scot. ? But OTOH the Scot has a 3 1/2 :1 purchase on the boom, whereas the Sailfish has 1 1/2 :1 (reckoning the part of the line from mid-boom to cockpit as the 1/2 in each case) — so the actual tension on the sheet may not be too different.

I say “this family of” block because mine is the 2135’s predecessor by 35 years, a 2 1/4” Harken Hexaratchet bought in 1984, but same size and with same mildly polygonal sheave in it — so the corners of the polygon in the sheave’s V groove act as modest jam cleats, adding up to a good belay effect when the ratchet’s on. ?(There’s a lever to flip that turns the ratchet off if you want, so that in light air you can play the sheet without drag — I suppose that's standard with most ratchet blocks.) ? The Hexarachet block was standard equipment on the fleet of Tech Dinghies I learned on, and it was great, so when I refitted the beat-up 1964 Tech I bought for myself (and still sail), I gave it one too, and have continued to think it’s great. ?(My boat is intermediate in sail size between Sunfish and Scot, and intermediate in mainsheet purchase as well, with 2 1/2:1. ?(The Scot has 3-part tackle at the stern, the Tech has 2, the 'Fish has 1.)

With any block that size, one nuance (or nuisance) is that in really light air it may tend to flop over and not pay out the sheet as freely as you’d like. ?But the remedy is easy, just bypass the block ?— run the sheet all the way out to park the stop knot at the block, and then play the sail purely by hand by taking hold of the sheet in the bight above the block. ? Or just play the boom itself by hand.

So unless Harken's new generation has managed to introduce some defect, I think you’ll like it.

Crispin