Saildrive boot keeps coming loose

[mjt2]

Hi, I have a 2003 Bavaria 38 Holiday with a Volvo Penta D2-50 and sail drive.  When I bought the boat, the "boot" around the sail drive was adhered to the bottom of the boat and stayed there for about 18 months. It got removed to bottom-paint, and then was put on badly by a terrible contractor.  A different contractor put on a new one and used a ton of 5200.  It stayed in place for over 18 months. Now 1 corner, maybe 1/4th of it, is hanging down again. 

Here are my questions, predicated on your having experience with this issue:
1. What "glue" do you use for your boot?
2. Is the "glue" you use something that can cure underwater, or do I need to haul out, apply, and have it cure for some period of time (if so, how long)?
3. I have researched various adhesives (mostly epoxies) that cure under-water, but am wondering if they will work against existing 5200 and/or gel-coat and the rubber boot?

Thank you very much in advance for your input and advice.

[MagicalArmchair]

Hey there,

The important part of the saildrive diaphragm is the bit that sits inside the boat. In the very, very low probability that were to fail you would have a rather large hole in your boat. Volvo recommends that is replaced every seven years - in reality, in my higher latitudes they can last much longer. In the tropics I think they do not last as long.

The hull seal that adheres to the hull is just to keep all the sea creatures out of the saildrive well, so is less important.

I used very cheap, but very very good CT1 for my hull seal when I redid Mirages diaphragm (not for the feint hearted  ).

[Moodymike]

Bostic 2 part. 2402 is the recommended product.  Used it 10 years ago,still in place.

[Happysailor]

Very important is the preparation of the outer seal before putting it on. I sanded the rubber (as advised by my VP guy) and also made sure the hull was completely free of previous glue (slight sanding with a multitool) and grease free, cleaning hull and seal surfaces with thinner. I used Sikaflex 291ii, straight on the hull, not on the Anti Fouling! Next important thing is to make it stick well. For this I used a small wall paper seam roller. This spreads the sealant evenly as well, excess is pushed out. Finish the outside rim well and remove excess. This lasted for over 5 years!