Anchor winch weight

[Danf]

Most anchor wells have more than enough glass in them, if however you have added more ply and glass then I would say that if you managed to rip it out then you would have to be doing something pretty silly. Most good boat builders add more glass in that area to stop bouncing anchors and chain banging/wearing through the hull whilst bouncing around in the sea plus the shape of that area would also add to the strength. Having said that there was no way it was even close to 50Kg more like 15Kg tops.

Did you join/extend the FRP to the sides or just add it to the top to cover the existing reinforcing? I did the same to my 26ft'er when I added a large winch to it. I did it mainly because I wasn't happy with the way it was originally done and so added the glass to the V sides as well as the top and back to the cabin sides, ie; completely glassed the well area, more so for wear and bumps than anything else.

But FRP is very strong so I wouldn't worry about it, if it is now about 50mm then that is about the thickness of a transom, and seeing as most 50mm transoms can hold 150HP -200HP motors I do not think that a 1 or 2 KWatt winch motor would do any damage even if snagged. Your boat probably would submerge itself by nose diving if you hooked it on the bottom whist driving forward fast and then you would have a different problem!
One last thing, 50Kg is a lot of glass and resin, are you sure you used that much?, that would be about a pail of resin and 2/3 of a roll of CSM glass.
Just my 2 cents worth.

Be aware that some of these winches can supply up and over 1000 kgf of line pull when the drum is empty of rope. While the same winch pulls with 200 to 300 kjf when full.
That is, the torque is greater when there is less rope on the drum. I suppose it is unlikely that a winch will be fully loaded when empty, and the person would use the boat to pull off the anchor if this happened anyway. Its like designing for the worse case scenario. I have seen bowsprits damaged by this very fact.

[ranmar850]

Yes, I've seen a cruisecraft bowsprit broken by a snagged anchor on a winch. And, as you point out, torque figures on the spindle are essentially meaningless , unless they translate directly to the sort of load you will have with the larger drum radius with most of the rope on, when you are more or less directly over the snagged anchor.

[Danf]

I know in the "old' days of pulling the anchor up using the "Armstrong Winch", one would pull the anchor up tight, then tie it off to the bow bollard, then motor forward. A stuck anchor would inevitably lead to the stern of the boat lifting, prop breaking out, and thus limiting the force applied. We did cut the line a couple of times when the anchor became wedged hard into a wreck. Divers did get quite a few anchors from the spot. The bow roller on those early boats were small and did not overhang by much. I would assume that with the extra leverage of long bowsprits and extended bow rollers, there may be extra bending forces on the bow.