Deck fittings question for AD14

[gonandkarl]

Hi,
I have to mount 5 deck blocks near the mast on my Adelie 14.
They are on the SB for Halyard, Yard hauling parrel and Topping lift hauling part and on PS for Luff hauling parrel and Topping lift hauling part.
My question is do they have to be screwed right through the deck with a washer and nut in the cabin or is it good enough to just screw them with wood screws into the mast partner which is 25 mm ( 1 inch) thick including the 6 mm of the roof ?
Near the transom I have to mount some bulls eyes for the sheet to lead the sheet forward. Do they also have to be screwed through the bench ? As it will be on the edge of the bench I have here also a thickness of 30 mm because the cleats for the 6 mm thick benches are underneath.The 2 sheet blocks will be mounted on a stainless steel bar which connects to the pushpits on both sides and the sheet goes from there down to the bulls eyes.
I must mention all this parts will have upwards forces.
Greetings from Karl

[Jaysen]

I'd recommend through bolting AND adhesive (5200). I'd also recommend stacked washers or a metal plate for load distribution. With a single washer the load will tend to focus on the area not much larger than the nut. The thicker the washer (in addition to diameter) the larger the distribution of force. If you go with a plate, consider using one plate to for all the through bolts. With adequate spacing from edges, this will be even better than stacked washers for distribution.

Either way, I don't think you want a simple lag for upward forces. If you can make the force lateral then the lag plus adhesive should be ok.

[terrulian]

Greetings, Karl,
Screws have very little strength except laterally, as Jaysen says. I'd second his suggestion for at least through-bolts, and better yet a backing plate.
Even laterally, I would prefer to have my deck cleats through-bolted. Screws can pull out under stress. Also remember that on a boat, even with a sealant, water can seep into the holes for the threads and compromise their holding power.
As is often suggested on this forum, drill all holes over-sized, fill with epoxy, and re-drill to the proper size. This will prohibit water intrusion into the plywood core.

[jacquesmm]

Trough bolts on backing plates.
If you can't reach with a nut, epoxy a thick ( 6mm +) plate to the inside surface then drill and tap for bolts.

[gonandkarl]

Hi,
Thank you so much Jaysen, Tony and Jacques. I thought that all answers will be to through bolting. I was just not sure and am glad that you had a common opinion. I like the idea of different size washers in addition to backing plates. As I still have the boat upside down I can easily install the necessary backing plates for the deck blocks. One of the bulls eyes is in the area of the backing plates for the PS rear cleat and pushpit which I have already installed. I just need another one in the PS bunk near the middle of the boat and is much easier to reach than the backing plates in the bunks at the transom. Thanks again.
Greetings from Karl

[Jaysen]

Karl, if you are using JM recommended backing plates then the need for washers changes. You simply need a flat washer to span diameter variations from plate to bolt and a locking washer to prevent loosening. I'd also recommend red locktite on the threads as well.

Also please take Tony's over drill advise. The one hole I didn't over drill and fill on Lil Bits solid wood mast is ALREADY showing signs of degradation. While the marine grade wood is much hardier than the pine I used on the mast, it's worth noting that ONLY that one hole is degraded. I'd hate to see that in a hard to fix hull area.

Now hurry up and get that boat done!

[das boot]

I can take a detail set of pictures of how I rigged my ad16 and send them to you this set up has worked well for a number of years

[gonandkarl]

Hi George,
Please send me the detailed rigging of yours. I am in the final stages and all ideas help.
Greetings from Karl

[das boot]

I will do that and send pictures on the week end