Boatlife life-seal........mildew resistant, fast curing, non-shrinking, Use above or below waterline. Its a mix of silicone and polyurethane.

3m 4200 never had any issues with installs - from rub rails to depth finders to pitot tubes to trim tabs and every darn screw or bolt that need it. Even fix some Formula boats that had their debonding issues for the shoe box fit the top cap to the hull.

3M has a 4000UV hybrid. "Hybrid" being polyether. White, kicks fast, good strength, UV resistant. Like Frank's Red Hot for boats.

http://multimedia.3m.com/mws/media/4...6580-06586.pdf

http://multimedia.3m.com/mws/media/7...oduct-info.pdf

+ 1. Been working on boats for over 30 years have always used Boatlife when installing below and above water fittings and drives. Never had any issues

Mark

3m 5200 only thing is it's forever

I have rigged this same set of boxes and drives on 3 different boats in the past 5 years. The first time I used 4200 and when we removed it from the first boat gelcoat and glass came with it. We used Life-seal for the second boat and it was much easier to remove with zero damage.

Better question - are either of these products, Lifeseal or 4200, available anywhere but a marine place? Like if I needed some in a pinch.

Ayuh,.... Yer Right,..... My bad,....

Glad to here about the life seal as that is what I have been using, screws included.

Here you can get the 3M product at Home Depot! But I have a couple of buddies with Lewis marine accounts so I just get the stuff there.

If you need the big 10 oz tube, haven't seen them anywhere except a marine place. However, if you need some in a pinch, you can get 3 oz. tubes of white 4200 and white 3M marine silicone at Academy stores (if you have them in OK.). One big tube is more than 3x the amount of the small tube and will cost less than two small tubes, even at West Marine.
At Academy, the 3 oz tube 4200 is $11.99 and 3oz tube Silicone is $12.99. Go figure....

I used LifeSeal mahogany color caulk on my antique wood boat and it dried out and started flaking off, even under varnish. I have used other LifeSeal products for other projects and they have done fine. May just be that particular product.