Attaching Cleats to the center board trunk

It's been less than an month that I have had my "77 DS II. I've been out on Lake Erie 4 times and pleased to say it's been smooth sailing. Thanks to Roger's book, I've upgraded a few things.
1. Placed cheek blocks on the mast for jib and main halyards. These are now run back to cleats on the cabin top.
2. Placed a cheek block on the mast for the cunningham. I've placed a fair lead and cam cleat on the cabin top to allow for easy adjustments.
3. My vang "V" cleat was always slipping. I took off the "v" cleat and ran this forward to a cam cleat as well. Everything is at my finger tips.
4. I added a rudder uphaul line and jam cleat. This is going to be great for clearing weeds etc. Which brings me to my question.
The area of Lake Erie which I like to sail has a fair amount of sea weed floating around. Boats and freighters entering the Detroit River chop it up and it floats to the surface. Certain areas "like heading back to the dock" cause me to clear the rudder and CB quite often. The addition of the rudder uphaul is going to be great. Now I'm looking to create an easier way to raise and lower the CB. It's currently setup with a standard cleat. I'd like to replace with a cam cleat with two cam cleats.
I'm wondering how the existing cleat is fastened and how I would fasten new cam cleats. Are these normally fastened with bolts or screws. If bolts, how can ensure that I don't create an access point for water and don't interfere with the CB.
Any help or advise would be great.
1. Placed cheek blocks on the mast for jib and main halyards. These are now run back to cleats on the cabin top.
2. Placed a cheek block on the mast for the cunningham. I've placed a fair lead and cam cleat on the cabin top to allow for easy adjustments.
3. My vang "V" cleat was always slipping. I took off the "v" cleat and ran this forward to a cam cleat as well. Everything is at my finger tips.
4. I added a rudder uphaul line and jam cleat. This is going to be great for clearing weeds etc. Which brings me to my question.
The area of Lake Erie which I like to sail has a fair amount of sea weed floating around. Boats and freighters entering the Detroit River chop it up and it floats to the surface. Certain areas "like heading back to the dock" cause me to clear the rudder and CB quite often. The addition of the rudder uphaul is going to be great. Now I'm looking to create an easier way to raise and lower the CB. It's currently setup with a standard cleat. I'd like to replace with a cam cleat with two cam cleats.
I'm wondering how the existing cleat is fastened and how I would fasten new cam cleats. Are these normally fastened with bolts or screws. If bolts, how can ensure that I don't create an access point for water and don't interfere with the CB.
Any help or advise would be great.