Upgrading sheet winches: use of an adaptor plate?

[NealB]

About 4 years ago, I bought a pair of Lewmar 43 self-tailers, to replace the smaller Barient winches fitted by Westerly.

At long last, I'm actually getting round to making the swap.

The existing winches have six, nicely spaced mounting bolts: the Lewmars will need five, not so evenly spaced.

So I could, of course, fill most of the existing holes, and drill new, or .........

I could make up a stainless adaptor plate that bolts through the existing holes, and then mount the Lewmars into five tapped holes in the adaptor plate.

I'd appreciate any informed opinions/ piss-taking, please, from the wide range of engineering knowledge amongst forumites.

 

[PeteCooper]

Either would work, but adding an adaptor plate would raise the winch, which may adversely affect the lead of the sheet to the drum of the winch.

 

[rogerthebodger]

When I changed the winches on my mast I did exactly that.

The winches on my deck are mounted on plates welded to the deck (steel boat) as shown below

https://flic.kr/p/WVi6c5

 

[NealB]

Either would work, but adding an adaptor plate would raise the winch, which may adversely affect the lead of the sheet to the drum of the winch.

Thanks, Pete.

I think that's unlikely to be a problem, but I guess it would be fairly easy to try a 'mockup' plate first.

 

[DownWest]

You would probably need something like 4mm plate and use countersunk bolts both ways. Otherwise, fine. Can't see 4mm changing a lead much, if the height of the winch is the same.

Countersunk holes would be easier than tapping ss

 

[Praxinoscope]

When I changed my winches, Lewmar to replace old Gibbs SR, I filled the old holes in the grp and re-drilled for the Lewmar,

 

[NealB]

You would probably need something like 4mm plate and use countersunk bolts both ways. Otherwise, fine. Can't see 4mm changing a lead much, if the height of the winch is the same.

Countersunk holes would be easier than tapping ss

Sorry, but just to make sure I'm not misunderstanding you .............

Are you visualising that the bolts that go through the base of the winch will also go right through the adaptor plate and through the grp of the cockpit coaming?

 

[DownWest]

Sorry, but just to make sure I'm not misunderstanding you .............

Are you visualising that the bolts that go through the base of the winch will also go right through the adaptor plate and through the grp of the cockpit coaming?

Nope, one set of bolts holding the plate to the GRP, countersunk to make the top flush, then another set facing up, to hold the winch base also countersunk against the grp. This was to avoid filling and redrilling the grp, which would be far easier..

 

[penfold]

Drill new holes and fill, as you're going up a size I'd make up a backing plate to spread the load. A lot easier than drilling 11 holes in a chunk of stainless steel plate(TBH these days for something like that which needs precision I'd draw it and send it to one of the CNC cutting places as they can do it faster and better than I can).

You would probably need something like 4mm plate and use countersunk bolts both ways. Otherwise, fine. Can't see 4mm changing a lead much, if the height of the winch is the same.

Countersunk holes would be easier than tapping ss

Most winch bases have countersunk holes in; will there be clearance from the rotating components to fit the ends of the screws, nuts and washers? Even if there is clearance bridging a countersink with a washer or tightening a nut into it is too bodgy for my taste.

 

[NealB]

Drill new holes and fill, as you're going up a size I'd make up a backing plate to spread the load. A lot easier than drilling 11 holes in a chunk of stainless steel plate(TBH these days for something like that which needs precision I'd draw it and send it to one of the CNC cutting places as they can do it faster and better than I can).

Most winch bases have countersunk holes in; will there be clearance from the rotating components to fit the ends of the screws, nuts and washers? Even if there is clearance bridging a countersink with a washer or tightening a nut into it is too bodgy for my taste.

Thanks, penfold.

I've got a friendly stainless steel handyman who's offered to do the necessary handiwork.

It was the factory counter-sunk holes in the winch bases that was confusing me.

 

[Fr J Hackett]

I changed the winches on my Vancouver 34 and simply epoxy filled the holes then drilled the new holes spaced as far away from the original filled holes as possible. Never caused a problem and was simpler and aesthetically better than introducing a spacer or plate.

 

[rogerthebodger]

Nope, one set of bolts holding the plate to the GRP, countersunk to make the top flush, then another set facing up, to hold the winch base also countersunk against the grp. This was to avoid filling and redrilling the grp, which would be far easier..

Mine winches were bolted down to the adaptor plate into tapped holes in the adaptor plate after bolting down to the mast base or the deck.

Unless you use nuts on the winch to hole the winch down bolts under the adapitor plat to bolt the winch down may not be possible

 

[Rappey]

If bolting down direct to the boat was good enough for the old winch then why not drill 5 new holes for your replacement winches ? Saves messing around with extra plates and fittings. I changed to larger self tailing and it took no time at all to remove the old, redrill and bolt down. Hex bolt heads fit nicely in the countersunk holes and easily clear the gears .
Would like to motorise mine, that will be much harder.

 

[bluerm166]

I used old marine grade ali plate 9.5 mm (which I had from old rudder stock and is easily worked) to overcome differing holes and to bring old and new winches into a better take-off position and further back clear of the sprayhood which both nhibited access and had windows at risk from raised levers.

 

[PaulRainbow]

Fill the holes with epoxy, drill new holes, fit backing plates under the deck, simples !

 

[doug748]

About 4 years ago, I bought a pair of Lewmar 43 self-tailers, to replace the smaller Barient winches fitted by Westerly.

At long last, I'm actually getting round to making the swap.

The existing winches have six, nicely spaced mounting bolts: the Lewmars will need five, not so evenly spaced.

So I could, of course, fill most of the existing holes, and drill new, or .........

I could make up a stainless adaptor plate that bolts through the existing holes, and then mount the Lewmars into five tapped holes in the adaptor plate.

I'd appreciate any informed opinions/ piss-taking, please, from the wide range of engineering knowledge amongst forumites.

I made transfer plates when I fitted new main winches. Made them from 6mm alloy wheel spacers something like this:

2 x 5mm Hubcentric Alloy wheel spacers Fits BMW X6 E71 F16 M 74.1 5x120 | eBay

There are loads available, so you have to juggle your requirements, I found the perfect diameter and manged to fit in the new holes no problem. Here is a snap of the new winch in situ:




Of course when I had done it I looked at the perfectly good alloy plates and thought - I wish they were stainless. So I got the local stainless people to laser cut copies. £110 which I thought was pretty good.

The plates are bolted down with countersunk set screws securing the winch, err I think. I must still have the original plates around somewhere so I can photograph them if you like.



.

 

[NealB]

Fill the holes with epoxy, drill new holes, fit backing plates under the deck, simples !

The old, and new, winches will, presumably, be subject to the same forces.

There's no backing plates for the old winches, and there's no signs of crazing on, or underneath, the coamings,, so why would the new wiches need them? Or is it just prudence doing her thing?

 

[penfold]

Going up a size allows winch grinders to apply more load and filling the holes with epoxy doesn't put back much strength, a back plate probably isn't necessary but it would be something I'd do.

 

[PaulRainbow]

The old, and new, winches will, presumably, be subject to the same forces.

There's no backing plates for the old winches, and there's no signs of crazing on, or underneath, the coamings,, so why would the new wiches need them? Or is it just prudence doing her thing?

As Penfold says in post #18

 

[NealB]

Going up a size allows winch grinders to apply more load and filling the holes with epoxy doesn't put back much strength, a back plate probably isn't necessary but it would be something I'd do.

Very sound advice: thank you.