Mid ship Cleat Backing Pads?

[xeitosaphil]

I am hoping to fit some 200mm mid ship Cleats once the weather gets better and have a question re backing plates. Because room is limited below the deck on the inside of the lockers I didn't want to use timber pads.

I did consider using S/S until I got a price for 2 x 300mm x 200mm x 5mm plates!

I also wondered about using 6mm aluminium but wondered if it might not provide enough rigidity, although the loading is in sheer so it might be ok . I know there are different grades of aluminium, and it has been suggested to use a tooling plate grade as it is stiffer but I'm not sure what the grade is called. What does the forum think to its suitability?

My other option would be to use 6mm steel plate which is readily available and considerably cheaper. Question is if I do, what is the best thing to coat the plates in, to stop them rusting?

I intend to bed the plates on a thickened bed of epoxy but thought I should coat them in something first, Epoxy paint maybe?

Along with the backing plates, I will have to put some epoxy dowel cores in for the bolts, because I think the deck is Foam Core Sandwich. I did think of covering the backing plates with fibre glass once fixed, but due to their positions in lockers, I gave up on that idea as it’s not easily achievable.

Any input would be most welcome,

Philip

Thanks in advance for any suggestions.

 

[Searush]

If you have a s/s fabricator near you, have a peep in his scrap skip, there may well be something you can cut & drill to your needs for scrap value only. I managed to make a complete bow roller fitting from scrap some years back with freely given scrap, but I did pay them to weld it up for me once it was ready for assembly.

 

[Blueboatman]

This is what I would do, ok, in your stated situation where you are unhappy with metal or wood 'visible' within the lockers ..

First locally recore the cored deck with epoxy- drill hole, hollow out using an Allen key in a drill, fill with epoxy mix( apply fan heater underneath in this weather too) ,, await curing,etc.

Then consider applying extra laminate underneath and not lumps of metal . This can be several layers of cloth 'all done at once' laid up onto an old kitchen cabinet door and then lifted and pressed into place against the deck head , ideally coming down generously onto the hull as well. This will be both strong and integral and blending in.

You can pigment the resin too, and trim the almost cured GRP with a craft knife, and when cured drill holes through, bed the cleat in Sikaflex and back it with washers on large washers and dome nuts.

 

[xeitosaphil]

" consider applying extra laminate underneath and not lumps of metal . This can be several layers of cloth 'all done at once' laid up onto an old kitchen cabinet door and then lifted and pressed into place against the deck head , ideally coming down generously onto the hull as well. This will be both strong and integral and blending in "

.


If I were to do it this way, how could I acheive a good bond to the existing fibre glass as it has all been painted inside the locker?

 

[Tranona]

12mm ply coated with epoxy and Sikaflex would be my choice in this situation.

 

[Blueboatman]

" consider applying extra laminate underneath and not lumps of metal . This can be several layers of cloth 'all done at once' laid up onto an old kitchen cabinet door and then lifted and pressed into place against the deck head , ideally coming down generously onto the hull as well. This will be both strong and integral and blending in "

.


If I were to do it this way, how could I acheive a good bond to the existing fibre glass as it has all been painted inside the locker?

Yup indeedy. Would it be simpler to get someone in and pay them/get them to teach you ' hands on' if you are not familiar with prepping old GRP? ( You need to remove the paint and abrade the surface BTW and degrease it with acetone. And determine whether it is paint or waxy gelcoat or flow coat applied by the builder...grizzly discs, grinders, chisels and Dremel tools, with a vacuum hose sucking simultaneously is a usual method...) ...

 

[Rigger Mortice]

I did consider using S/S until I got a price for 2 x 300mm x 200mm x 5mm

Those are seriously big backing plates and I can't believe they need to be that size for a modest 200mm cleat. How big is your boat?

FWIW I have mild steel internally mounted backing plates and have had no problem with them. Some are galvanized, some painted with Hammerite. So long as the fitting is well sealed so that water doesn't get through they should be fine

 

[jwilson]

Yup indeedy. Would it be simpler to get someone in and pay them/get them to teach you ' hands on' if you are not familiar with prepping old GRP? ( You need to remove the paint and abrade the surface BTW and degrease it with acetone. And determine whether it is paint or waxy gelcoat or flow coat applied by the builder...grizzly discs, grinders, chisels and Dremel tools, with a vacuum hose sucking simultaneously is a usual method...) ...

Correct, but the extra GRP is not going to move much once two big bolts through the cleat hold it in place - certainly there should be no shear forces to debond it even if the bond is not perfect. The only action that will debond it is flex of the cored deck and hull itself.

 

[doug748]

I would not want to use mild steel at any price, ally is also likely to corrode badly, sooner or later.

One forum member cut up an old plastic chopping board (basically polythene, I think) and used penny washers.

As Searush has suggested, stainless should not be that pricy, esp if you are doing the drilling and trimming. I should have another ask around. Don't overdo the size thing, in the golden age of British yacht building it is the sort of thing that would be fixed in place without backing plates or even washers :-}

 

[Poignard]

12mm ply coated with epoxy and Sikaflex would be my choice in this situation.

Mine too

 

[xeitosaphil]

Those are seriously big backing plates and I can't believe they need to be that size for a modest 200mm cleat. How big is your boat?

FWIW I have mild steel internally mounted backing plates and have had no problem with them. Some are galvanized, some painted with Hammerite. So long as the fitting is well sealed so that water doesn't get through they should be fine

I didn't consider that the backing plates were seriousley oversized? The actual cleats are Allen YS7109B Deck Cleats with 4 x 8mm hole fixings.

The plate overhang on the cleat base is only 60mm each side in width, and 112mm overhang each end in length.

The side ways stressed involved with using the cleat will tend to want to lift the end of the cleat where the resistance from the rope is, out of the deck, so I thought that the extra length would give it more surface area to reduce the lifting stresses?

The plate is only the extra width so it will get extra support from the side of the hull where it will be reinforced with the thickened Epoxy?

The boat is 30 foot and weighs 5 1/2 tons rigged for cruising, so not that lightweight.

I have attached a couple of photos of my proposed idea for scutiny and comments?

I must admit I don't like the idea of using Mild Steel Plate unless really well coated with something? Maybe I will have to look again for a cheaper supplier of S/S

 

[Rigger Mortice]

I didn't consider that the backing plates were seriousley oversized? The actual cleats are Allen YS7109B Deck Cleats with 4 x 8mm hole fixings.

The plate overhang on the cleat base is only 60mm each side in width, and 112mm overhang each end in length.

The side ways stressed involved with using the cleat will tend to want to lift the end of the cleat where the resistance from the rope is, out of the deck, so I thought that the extra length would give it more surface area to reduce the lifting stresses?

The plate is only the extra width so it will get extra support from the side of the hull where it will be reinforced with the thickened Epoxy?

The boat is 30 foot and weighs 5 1/2 tons rigged for cruising, so not that lightweight.

I have attached a couple of photos of my proposed idea for scutiny and comments?

I must admit I don't like the idea of using Mild Steel Plate unless really well coated with something? Maybe I will have to look again for a cheaper supplier of S/S

At a guess I would have thought that a plate one quarter the size of what you are proposing would be more than adequate. But have a look and see what size the plates are on your bow and stern cleats; you'll probably be surprised how small they are.

TBH I don't know if there is a rule of thumb for sizing backing plates but there must be some recommendations somewhere.

 

[Sneaky Pete]

I used s/s penny washers and nylock nuts. Finished off with white plastic hexagonal nut caps. Perfect.

 

[Amulet]

Mine are 5/8 ply and Sikaflex. I always have a dilemma with things like this. Do you epoxy it rigid up to the eyeballs so that it never moves, or do you bathe it in Sikaflex so that if it does move it doesn't break the seal? On my wooden boat I'd normally accept that movement is inevitable and go the Sika route.

 

[ghostlymoron]

I would avoid metal backing plates unless the panel is absolutely flat. The backing plate needs to spread the load and have a bit of give in it to avoid introducing point loads. Chopping board or marine ply would be my choice.

 

[LadyInBed]

Why new s/s?
Raid the kitchen, charity shops, scrap yard, council tip for old s/s pans, lids, engineering works off cuts.
Go to work with an angle grinder and Bobs your backing plate

 

[LadyInBed]

I would avoid metal backing plates unless the panel is absolutely flat. The backing plate needs to spread the load and have a bit of give in it to avoid introducing point loads. Chopping board or marine ply would be my choice.

I used both on mine, ply for depth and contour s/s as a big rectangular washer.

 

[James_Calvert]

I am hoping to fit some 200mm mid ship Cleats once the weather gets better....

Please forgive this probably unhelpful post, but someone needs to ask it - at least someone usually does!

Do you really need midship cleats?

I can see the point of them, but have managed without on my 32 footer for many many years and so the bother of putting them in just doesn't seem worth it.

 

[ghostlymoron]

I used both on mine, ply for depth and contour s/s as a big rectangular washer.

That would be fine.

Please forgive this probably unhelpful post, but someone needs to ask it - at least someone usually does!

Do you really need midship cleats?

I can see the point of them, but have managed without on my 32 footer for many many years and so the bother of putting them in just doesn't seem worth it.

Midship cleats really make single handed berthing so much easier on anything over 25' or so but not necessary on my 19 footer. If you can manage your 32 footer without them you are obviously a skilled boat handler - hats off to you!

 

[James_Calvert]

Actually I've not had them for so long they'd probably be a danger to me - I'd trip over them...

Generally once the boat is stopped alongside I get off smartly with the lines and do the necessary. Of course it's easier if someone lends a hand to steady the boat before I've got both springs on... my overhanging pulpit makes a good handhold for this purpose.