Problem windlass mounting

[ThereAndBack]

I have an old vertical windlass (Lofrans Airon) I'm about to replace. It is mounted on a fiberglass shelf below decks in a locker. The problem is that how it is mounted doesn't provide access to the thru bolts that hold the windlass down. There are bulkheads on two sides of the shelf that allow less than 3" clearance. The aft bulkhead, maybe only 1". I can't really figure out how to remove the old windlass without destruction. So that said... Here is my plan, please critique.

I plan to cut the old windlass out by making a hole in the shelf. I plan to cut out the shelf to the dimensions of the top of the old windlass (approx 7"x10"), this will let the windless drop out the bottom of the shelf.

I will then make a spacer to fill the hole. I will bolt a 1/2" G10 board onto the bottom of the shelf with bolts every 1/2" all the way around. I'll bond the spacer onto the G10 and mount the new windlass ontop of the spacer. That should allow me to drop the new windlass out when required in the future.

Thoughts?

[ThereAndBack]

I actually found this in the old Lofrans Airon manual:

In order to facilitate maintenance operations Lofrans
suggest to install the windlass on a removable panel fixed on the deck by bolts.

This makes me feel somewhat better about things.

[tkeithlu]

I'm glad you are feeling better about it. You've run into one more example of designers saving space to the point that maintenance is just about impossible.

QUOTE:"with bolts every 1/2" all the way around." This caught my eye. Spacing of bolts is a function of the flexibility of the material being bolted. If you really need bolts that close together, use thicker/stronger marterial.

[ThereAndBack]

Originally Posted by tkeithlu

I'm glad you are feeling better about it. You've run into one more example of designers saving space to the point that maintenance is just about impossible.

QUOTE:"with bolts every 1/2" all the way around." This caught my eye. Spacing of bolts is a function of the flexibility of the material being bolted. If you really need bolts that close together, use thicker/stronger marterial.

I'm probably just being paranoid because I'm ignorant. Do you have a suggestion on correct size/spacing? The fiberglass shelf is 1/4" thick and I'll be putting a 1/2" thick G10 backing plate behind that. I'm not anticipating a lot of flex from that material.

[tkeithlu]

OK. Not a problem. Let's think it through. When you drop out the windlass, take a look at the bolting used to attach it to the original shelf. That worked, so you can use it as a guide. The 1/2" plate is sturdier than the original shelf. You will bolt the new windlass on the plate in a similar manner. Now you've got the package and need to bolt it on to the remains of the original shelf. Your bolts will be farther from the windlass than the bolts holding the windlass to the plate. That means they have a longer arm with which to hold the package from turning rather than pulling in your rode. If you use the same size bolts in the same pattern, just farther from the windlass, they will be strong enough. If that's not clear, send me a private message and we'll move to photographs and drawings. Good luck with it.

[ThereAndBack]

Originally Posted by tkeithlu

OK. Not a problem. Let's think it through. When you drop out the windlass, take a look at the bolting used to attach it to the original shelf. That worked, so you can use it as a guide. The 1/2" plate is sturdier than the original shelf. You will bolt the new windlass on the plate in a similar manner. Now you've got the package and need to bolt it on to the remains of the original shelf. Your bolts will be farther from the windlass than the bolts holding the windlass to the plate. That means they have a longer arm with which to hold the package from turning rather than pulling in your rode. If you use the same size bolts in the same pattern, just farther from the windlass, they will be strong enough. If that's not clear, send me a private message and we'll move to photographs and drawings. Good luck with it.

I really do appreciate your help and concern. Thank you!

The windlass is held in place by 4 studs. So if I'm understanding you correctly, you're saying four corners of the new plate would be good enough. I may add at least a couple more just to make myself feel better.