Resizing Winches

[Stumble]

I have been sailing on a Columbia 50' for the last year or so, and recently we have replaced the old 155% Jib with a much larger 170%. The sail works great, but the old winches are pretty slick, and even with the maximum wraps we can get on the drum the line still pulls to hard on the sheet.

The owner and I were talking about replacing the winches, but aren't really sure what the best option would be. Any thoughts would be appreciated.

[Brion Toss]

Hello,
There are some things that might be driving this problem besides winch power. One is that the existing winches are powerful enough, but need maintenance; old grease, the wrong type of grease, too much or too little grease, can all siphon power away.
Lead to the winch can also generate friction, if it is too low. And too-tight stripper grooves can generate excess friction. These problems might have been masked by the smaller sail.
But if all else is well, it's about the load. Calculate the load on the sheet (Harken catalog has the formula, as does the Apprentice), and divide the result by 35. This should give you the power of the winch you need.
Fair leads,
Brion Toss