Pad eye backing plates

[wonkywinch]

I'm going to fit some pad eyes, folding and non folding for clipping on and for blocks for my Code 0.

I intend to bolt them through the deck and wondered what type/thickness of steel to fabricate a backing plate with? The pad eyes I plan to use have 2 or 3 holes.

If stainless is recommended, can I drill this with a battery drill? Online tips seem conflicting.

 

[zoidberg]

'How long is a bit of string'.....

I'm in process of fitting very beefed-up deck cleats, 250mm, to take mooring and ( possible ) towing loads. There are teak backing pads about 200mm x 180mm below the 10-11mm solid grp deck, and 2.5mm s/s sheet even larger, which bridges across two glassed-in deck beams.

Of course, the purpose of the steel sheet is to help spread loads into larger areas of grp. A suitable bonding compound will help with this.

While drilling that s/s sheet today, I used a 3mm drill bit initially in a drill press, then a 'titanium-coated' step drill bit to enlarge the pilot holes to accept the 8mm through-bolts. It was quite hard work for the drill press, using quality drilling/tapping paste. My hand-held 14.4V battery drill would not even touch it.

 

[William_H]

As said it will be hard work drilling SS with a hand held drill. The best way is a drill press where you can get great drill pressure at low speed. One of the problems drilling SS is that the material work hardens so the more you persevere the harder it gets. Use a sharp drill with lots of pressure and some oil lubricant can help. If you don't get noticeable swarf cuttings you are doing it wrong. Oil helps lubricate but also gives a good indication of over heating with smoke.
Perhaps easier to use thick GRP as a backing plate. (use large metal washers) Either buy it as a board or cast it yourself from polyester or epoxy resin and bolt in to place. You could lay up glass and resin in situ but upside down this is difficult. ol'will

 

[rotrax]

Island Packet use thick aluminium backing plates.

I fitted two threaded eyes-12mm ones-and used some 10mm aluminium plate I had left over from my motorbike racing days. I threaded them and then used locknuts.

It was high quality duralumin plate, from GKN at slough.

 

[rogerthebodger]

I would use 6 mm thick stainless steel drilled and tapped for the setscrews through the pad eye from the top so that id the pad eye gets damages they can be removed from the deck outside

I do use a bench drill most of the time but I do use my 18v battery drill to drill 316 stainless.

The trick is slow speed and sharp drill and ensure the drill always cuts and not just rub

I tend to start with a 5 mm drill and too small will blunt quickly of barke dur to high drilling pressuer

 

[Neeves]

I'm going to fit some pad eyes, folding and non folding for clipping on and for blocks for my Code 0.

I intend to bolt them through the deck and wondered what type/thickness of steel to fabricate a backing plate with? The pad eyes I plan to use have 2 or 3 holes.

If stainless is recommended, can I drill this with a battery drill? Online tips seem conflicting.

It depends on your battery drill. My little Black and Decker would be a waste of time.

Jonathan

 

[NormanS]

The important thing is to use a sharp drill. The rotating machinery is of secondary importance.

 

[rogerthebodger]

The important thing is to use a sharp drill. The rotating machinery is of secondary importance.

!000% agree.

A battery drill can have an advantage due to its slower speed.

The other thing is pressure to endure the drill is cutting and not just rub

 

[boomerangben]

Without know boat size, deck construction, geometry and so on, the question is unanswerable. The answer could range from penny washers to something far more substantial.

 

[zoidberg]

Without know boat size, deck construction, geometry and so on, the question is unanswerable.....

That's never been known to be a restraint in 'ere.

 

[Neeves]

It you simply add a 6mm x 100mm square plate of SS, epoxied to a slightly larger in area but heavy weight glass pad it will cover most eventualities in most yachts (of a size owned by most here).

I suspect the fixtures holding the pad eye are most likely to be the point of failure (unless its a really hefty pad eye (like Zoidbergs).

Jonathan

 

[VicS]

Deleted

 

[thinwater]

Don't use stainless. Use structural fiberglass plate. Properly tapered and bonded it becomes part of the boat. If it were a factory part of the boat they would probably have just layed that area up thicker, which is another option (add ~ 3/16" of 1708 cloth to the underside). Then use double-thick penny/fender washers to spread the load to the GRP plate/laminate. The main advantages of stainless in this application are that it is more expensive, harder to work, harder to seal, heavier, and does not add shear strength. Oh, and it's shiny.

Aluminum also works well. Very easy to work.

I've only used stainless a few times, always because I had a bit of scrap 316 and was out of GRP plate.

 

[zoidberg]

Those who know me and my legendary polytunnel will not be surprised that I've found four of 'thinwater's structural grp plates each 630 x 750 x 13mm under some other stuff I'd forgotten. Now I'm looking for a new task or two....

The foredeck needs reinforcing in way of a hefty U-bolt for an inner stay. Now, should I use one slice of 13mm grp plate, or two....?

My tame shipwright tells me he'd just bond in a half-metre chunk of half-inch ply and cover it in glasscloth. What thinks the hivemind?

 

[justanothersailboat]

I think your shipwright is a shipwright and I'm not, so my opinion counts for much less, but I really do worry about ply and water ingress. Even though I have fitted ply backing plates myself and when I've dug out rotten ones it's usually been because someone did something quite wrong to the seal. If your shipwright thinks half inch ply glassed in is structurally enough, then one 13mm GRP plate sounds like a really tempting option to me if you can get the edges to join over a nice big area rather than making a sharp transition.

 

[wonkywinch]

The boat is a 2016 Beneteau WPB with artifical teak. I want to fix pad eyes approx here. Penny washers prob no good as the screw holes will be too close.

These will be utilised for Code 0 block and/or jackstay.

 

[zoidberg]

.....I really do worry about ply and water ingress.....If your shipwright thinks half inch ply glassed in is structurally enough, then one 13mm GRP plate sounds like a really tempting option to me if you can get the edges to join over a nice big area rather than making a sharp transition.

Yup.

He's probably thinking of the remnants of my life expectancy vs how long it takes for decent ply to rot.....

I'll fit one ( or more ) 13mm grp plates to span between two glassed-in transverse original deck beams. These have filleted bases, so I can probably match the curves, approximately, and 'mind the gap' with thickened epoxy.