1985 Hunter 34 Winch Backing Plate Question

[c07chrisjohnson]

Hello Everyone,

I'm in the middle of replacing the Maxwell winches on my 1985 Hunter 34 with new Lewmar 40s and 45s (40s for the cabin top and 45s for the Jib sheets) I'm wondering what everyone thinks about backing plates for the new winches, are they necessary?

There were no backing plates installed on any of the original Maxwells. So far I've removed the old ones and epoxied the holes shut. During the removal of the old winches I noticed that the bolts were threaded into the gelcoat/fiberglass on every winch.

I was planning on drilling holes just slightly larger than the bolts, using butyl tape to seal the bolts, and using washers and nuts---still havent decided on using backing plates. I bought some G10 to use as a backing plate but today I noticed, while checking the inspection port on the port side in the sunlight, that there seems to be some kind of plate glassed into the hull. The picture labeled topside is just to show the area I am talking about. The other two pictures are looking at the same area from underneath, you can clearly see something in the fiberglass. I have no idea if its Stainless, regular steel, aluminum, wood, etc...

I'm not sure if there is a similar plate in the fiberglass on the cabin top.

What do you all think?

Backing plates or not, or do I need to use a tap to thread the new holes to take advantage of the integral plate?

 

[Ryan and ileana Bradley]

I spoke with Hunter some years ago about how the deck organizers were installed as I didn't see the bolts or nuts protruding from inside the cabin. They replied that there was an aluminum plate that the bolts threaded into under the organizer. I also got aluminum shavings when I drilled into the area just forward of the winches to install a fitting. So, I hope that helps in making your decision to install or not install a backing plate. I have thought of replacing the old Maxwell's but haven't gotten around to it yet, you will have to keep us posted on how your project turns out!

 

[Tally Ho]

I don’t have a Hunter, but I am replacing the primaries on my 1988 O’Day 322. I was surprised that there were no backing plates under the winches…just a washer.

When I drilled the new holes, I got some wood shavings, so I assume that Oday put some plywood under the winches.

i read somewhere recently that given the force on the winches is in shear, little chance of the bolts pulling through the fiberglass.

But nonetheless, I added some backing plates under the winches…belts and suspenders I guess.

Greg

 

[jssailem]

Inspecting the images that is daylight coming through the center of the holes ?

Assuming the hole pattern of the new winch does not match the old winch.

I would drill the through holes. Use backing plates to manage the stress on the deck from the winches. Secure the bolts and backing plate with large washers with nuts.

Did that this year on my boat. I have fiberglass deck no inner plate. The backing plate is 3/16” aluminum. It spreads the stresses across the area that the winch is secured. G10 also works well for this task.

What does not work well is just fender washers to the bolts. The fender washer eventually bends, the forces on the winch collapse the deck and given time and enough sailing the winch can be ripped off the deck.

This is unlikely on a daysailor when only sailing in good weather. It becomes a concern on a boat used in open water passage where bad weather conditions can occur and you place the boat under considerable stress. (I.e.racing Newport to Bahamas).

 

[c07chrisjohnson]

Inspecting the images that is daylight coming through the center of the holes ?

Yes, sunlight is coming through the holes I filled with epoxy, I used West system, didn't use any pigment so its pretty much clear.

Will keep the thread updated with the progress. I think I am going to use the G10 backing plate route, good points above, and it can't really hurt to be too strong, factor of safety is always good.

 

[kloudie1]

There is an aluminum plate imbedded in the area of the shadow. I don't remember if it is 3/16 or 1/4, but it is strong enough that no further backing plates are necessary. The winch mounting bolts were threaded into that plate. My PO added some larger winches in addition to the original Maxwells. He thru drilled and bolted from below with washers but no additional backing plates.. All is good after many years. There is no plywood in that area.

 

[c07chrisjohnson]

kloudie1, are the bolts threaded into the fiberglass?

 

[markwbird]

I did this. No backing plates needed

 

[kloudie1]

The original bolts are threaded into the aluminum plate imbedded in the fiberglass. There are washers and nuts on the ends stat come thru to the inside.The cabin top winches and clutches are done that way too, but without the inner nuts. My additional winches have the holes thru-drilled and have washers and nuts on the inside. If you've filled the old holes, you can drill for the new winch, staying away from the old holes. The holes should not be oversized. Then washers and nuts on the inside.. The embedded plate is the backing plate. You can add a backing plate but it is not necessary

 

[Blitz]

Remember you are dealing with dissimilar metals here (stainless bolt into aluminum backing plate.. Use of Lanocote or Tel-gel is highly recommended.

if through bolting the deck to a backing plate not imbedded, would recommend G10 or Stainless with rounded corners to prevent stress risers.

 

[artboas]

Remember you are dealing with dissimilar metals here (stainless bolt into aluminum backing plate.. Use of Lanocote or Tel-gel is highly recommended.

if through bolting the deck to a backing plate not imbedded, would recommend G10 or Stainless with rounded corners to prevent stress risers.

 

[artboas]

Hunter glassed aluminum plates into the hull.
they then threaded them, and put nuts and washers on.
This gave more than enough strength to the mounting.
If you are installing new winches with a different bolt hole pattern, then just fill the original holes, re-drill & tap.
Then, install nominal washes & nuts underneath. This is more than strong enough
Caution !!!!
When you are re-tapping the holes, use a good quality tap, cutting fluid, etc.
If you break off a tap in your deck, it will be a very bad day

 

[c07chrisjohnson]

I ended up not using the G10 backing plates, became too much of a pain in the a$$. I ended up tapping the the bolts through the aluminum plate then using washers, basically replicating how they were installed from the factory. I sail out of Marina Del Rey in Southern California and do not anticipate sailing during bad weather, so this method should suffice.

 

[Tally Ho]

I ended up not using the G10 backing plates, became too much of a pain in the a$$. I ended up tapping the the bolts through the backing plate then using washers, basically replicating how they were installed from the factory. I sail out of Marina Del Rey in Southern California and do not anticipate sailing during bad weather, so this method should suffice.

Looks very nice.

If you have aluminum plates in the coaming, you should be fine.

Greg

 

[Crusty Ol Salt]

Hunter glassed aluminum plates into the hull.
they then threaded them, and put nuts and washers on.
This gave more than enough strength to the mounting.
If you are installing new winches with a different bolt hole pattern, then just fill the original holes, re-drill & tap.
Then, install nominal washes & nuts underneath. This is more than strong enough
Caution !!!!
When you are re-tapping the holes, use a good quality tap, cutting fluid, etc.
If you break off a tap in your deck, it will be a very bad day

Question about the Hunter plates glassed into the hull. Are they glasses into the hull were the optional winches were not installed?

 

[artboas]

Question about the Hunter plates glassed into the hull. Are they glasses into the hull were the optional winches were not installed?

Yes, on my boat they were. It was zero effort for Hunter to glass in the plates, and at that point in production, they didn’t know all of the option details.
But, if you want to be 100% sure, when you have your hole pattern, drill a 1/8” starter hole.
Look on the drill flutes, and I’m sure you’ll see aluminum
Or, you could buy an “aluminum magnet” . It’s made by the same incredible engineers who are putting in a 1000km /hour train in Canada. Go to Eev blog to see a great video on this .

 

[artboas]

Yes, on my boat they were. It was zero effort for Hunter to glass in the plates, and at that point in production, they didn’t know all of the option details.
But, if you want to be 100% sure, when you have your hole pattern, drill a 1/8” starter hole.
Look on the drill flutes, and I’m sure you’ll see aluminum
Or, you could buy an “aluminum magnet” . It’s made by the same incredible engineers who are putting in a 1000km /hour train in Canada. Go to Eev blog to see a great video on this .

BTW,,, they’re calling their technology “Fluxjet”
I’m 100% serious .

 

[Crusty Ol Salt]

Yes, on my boat they were. It was zero effort for Hunter to glass in the plates, and at that point in production, they didn’t know all of the option details.
But, if you want to be 100% sure, when you have your hole pattern, drill a 1/8” starter hole.
Look on the drill flutes, and I’m sure you’ll see aluminum
Or, you could buy an “aluminum magnet” . It’s made by the same incredible engineers who are putting in a 1000km /hour train in Canada. Go to Eev blog to see a great video on this .

I figured as much on the backing plates. I think I read it somewhere on here previously.

I thought about a magnet before I asked. Then I decided that a magnet would not work on aluminum....

Thx for the info. Off to read about "Fluxjet" now.

 

[artboas]

I figured as much on the backing plates. I think I read it somewhere on here previously.

I thought about a magnet before I asked. Then I decided that a magnet would not work on aluminum....

Thx for the info. Off to read about "Fluxjet" now.

Everyone needs to go to the EEV blog site and look at the video on Fluxjet. It’s a high budget kickstarter with even more BS than Theranos.
It’s unbelievable that the Alberta govt has thrown money into this.
The “demo” they put on for the investors (on video), was an April 1 production. But, investors are using someone else’s dough., Why bother to ask a grade 12 physics student if this is viable

Btw,,,
Here’s the link