Alberg 37 MK!! 1975 - bilge floor glassing

[Oldsailor27]

Hi there.
I had to remove some of the bilge floor as there was some delamination in the tabbing and water and engine oil has gotten into the incapsulated keel area.
Apparently under the aft part of the bilge floor there is only packed sand in the keel cavity, the lead ballast ends at the line of the last bulkhead which separate fuel tank and bilge area.
I have dremmeled as much bilge floor as I could and cleaned up the oily sand and wet send from the under the floor area. Have run a de humidifier for several days so the remaining sand is quite dry and packed.
Now I need to fill in this space,- pour some mortar, concrete or mix up west system epoxy with 209 hardened and 2 parts play ground sand or high density foam or anything to get it filed and sealed.
My concern is that there is some tabbing delamination is still there and it's impossible to reach it to grind it off. It about 4 inch high.
I am thinking of filling the bilge to the top of tabbing line and pour some thicken epoxy on top. Would it create a waterproof seal as I hardly could sand the hull from the inside to allow a proper adhesion surface for epoxy to stick in.
If anybody have an idea to to approach with repair please pass it on as I am pulling my left of heir dreading this repair

[Bowdrie]

Is the boat on the hard?
I would not leave the sand in there.
Getting that sand out and cleaning that area, (perhaps a pressure washer,) would be a good start to determining further action.
If possible, weigh the sand that's removed, its weight probably has some effect on the trim of the boat, (it's hard to judge without scale/depth known).
With a nice/clean "cavern/cave" the best way to proceed will become more apparent.
Edit: Is this the extreme aft end, in other words, might the heel fitting for the rudder be hidden under the remaining sand, (the bolts going thru a solid section at the bottom)?
Nice boat.

[Oldsailor27]

The boat is on the hard. This is the extreme aft end very hard to reach area.
The rudder sits on a bronze rudder shoe bolted to the lower end of the keel.
I have removed the old blown diesel (all the oil was in the bilge and some found the way to the keel cavity which I have already removed.) I will be putting electric motor so I would need to do some additional ballasting work down the road.

[Don C L]

I am not sure if I can help here or not but I have the same cavity on my keel which was left empty. My feeling is to go with the epoxy cap over the concrete. Now if it is not waterproof, what is the down side? The only one I can imagine (and it is not insignificant) is that if you are hauled out in an area where it freezes you could have problems with the water down in there. Still I think the cap would end up waterproof if the area that your can reach above the sand is cleaned well and scrubbed with acetone.

I don't know how accessible it is, but if it needs the weight back there, how about vacuuming out the sand and store extra chain in there? (Though that could be a problem if the boat is ever inverted)