A Frame fittings

[andrewe251003]

What’s the best method for bolting down the base of an A frame if you can’t get to the underside of the deck?

I had to remove the A frame off my Humber to get a new steering cable in. Whilst there I noticed that the a frame base plates are held down with 2 coarse threaded screws per side with a 17mm hex head on them, straight in to the deck. No idea whether this was original at the factory but the screws don’t really ‘tighten’ down and don’t feel like they would take much torque.

Is there a better way of holding the base plates down by using some sort of helicoil in resin and s/s machine screws?

TIA

[boristhebold]

Should be bolted not screwed, my advice would be to look at a method of bolting the a frame down, they must have to take a lot of strain.

[spartacus]

Should be bolted. Is there any access? Ideally you wanted stainless steel backing plate under deck to spread load. What about the witches hat (assuming you have under deck conduit for fuel and engine cables) where you could at least see or feel under deck.

Not convinced about helicoil glassed into deck. Any pictures?

[Nasher]

I think you're going to have to add an access hatch or two so you can get your arm down under the deck and put some nuts on bolts under the deck.

You know it's the right thing to do.

Nasher.

[andrewe251003]

Originally Posted by boristhebold

Should be bolted not screwed, my advice would be to look at a method of bolting the a frame down, they must have to take a lot of strain.

This my concern. The frame is bolted through the transom with M12 stainless fasteners and nylocs. It’s screwed to the deck with 4 of these. these.

[andrewe251003]

Originally Posted by spartacus

Should be bolted. Is there any access? Ideally you wanted stainless steel backing plate under deck to spread load. What about the witches hat (assuming you have under deck conduit for fuel and engine cables) where you could at least see or feel under deck.



Not convinced about helicoil glassed into deck. Any pictures?

Control cables run through the console and across the deck like this. so there’s currently no under deck access apart from the drain bung in the bilge well.

[andrewe251003]

Originally Posted by Nasher

I think you're going to have to add an access hatch or two so you can get your arm down under the deck and put some nuts on bolts under the deck.

You know it's the right thing to do.

Nasher.

This is the deck plate for the frame. I’d be a lot more comfortable with bolts through and a plate on the underside. Not done that before though so slightly nervous about taking a holesaw to my deck.

[spartacus]

Step away from the hole saw!

If you look at the self tappers, you've effectively got 1-2mm of the thread that's holding the A-Frame to the deck, but it's bolted to the transom too, so it's not going anywhere, but you said it yourself there's no security with self tappers.

The access hatch needs to be watertight, so don't scrimp on the quality. Bed in with Sikaflex 291 and screw down with s/s self tappers. I'd also glass the exposed deck plywood once it's cut to seal.

Here's what's on Humber's site. https://www.ribworld.co.uk/hatches/

I quite like these in marine stainless steel from Osculati. Means you can safely walk on it and it's not going to flex. (Note - key not provided)
https://www.floatyourboat.co.uk/insp...BoCwdkQAvD_BwE

You'll need details from Humber regards what's under the deck in terms of the location of stringers. I suspect you'll need two access hatches?

[andrewe251003]

Thanks for the replies. It’s a pain but ultimately needs sorting.

I’ll have a chat with Humber about what’s under there and see how much room there is. The outer edge looks close to the hull so it may be tight.

Hopefully they will update their pricing on that website. £100k for a hatch!!

[spartacus]

Osculati ones are £60-80 which I thought was pretty reasonable for 316 grade. If nothing else adds a bit of bling.