Sikaflex-291, White, General All-Purpose Fast Cure Marine Adhesive and sealant. Polyurethane sealant for Boats, 10.1 fl. oz Cartridge (Pack of 1)

Used this to fill the seam between the hull and deck. Used an electric calking gun allowing for controlled flow into the seams which were 22ft runs from stern to bow. took two tubes of Silkaflex. While fresh it was easy to use a scraper to push this material deeper into the seam and simple to remove excess leaving a smooth seam level with the deck. It took several days to harden to my satisfaction and in the meantime collected a layer of dust onto its surface. Once painted there is a subtle but clear discoloration showing through the paint. It's a good product but as this was a restoration job on a classic wooden boat I think epoxy would have been a better choice. But, no complaints with how this material works and I'm sure it will hold up for some time as the hull and deck flex a bit with movement and with the natural swelling and shrinking inherent in wood.

This is really good RTV! I didn't know Silksflex existed until I had to change out a pair of jet drives on a Zodiac Hurricane. Silksflex RTV was the recommended by the OEM manufacturer. I use Silkaflex on Motorhomes, trucks and around my house. Very strong and flexible and seawater resistant.

Each type of caulk has its own purpose and this is not structural quite obviously. I like the fact that It can be above or below the waterline but I would not ever use this below the waterline. As I suspected there are better ways; that said knowing that they don't have a problem with it being underwater makes me feel a lot better about it being above water on my deck. Acting as a sealant.

Works the way it should.

TWICE I RECEIVED AN EXPIRED PRODUCT WITH ZERO RESPONSE FROM THE COMPANY. The product arrived expired. It was expired four days before I even ordered it. Sikaflex customer service is nonexistent. They did not return any of my messages. Thankfully Amazon stepped in to have it replaced. No wonder people don't care to buy USA made products. The label very clearly states the warranty is only applicable for the product shelf life. The product quality and cure time is not guaranteed after expiration date.

Wonderful, grippy, but gooey to apply - super great adhesion - but absolutely need humidity such as East or West coast, near water, Great Lakes or humid Georgia. I live in Colorado and it is still gooey on my sailboat - called the company - they said need 50-60% humidity or it won't dry. Used in my bathtub and I had to leave hot steaming water in the tube twice and it adhered perfectly. Otherwise would be 5 stars in a humid climate. 2 stars for Colorado - but it's not chemical reaction for drying - it's reactive to humidity.

Been using it for years in marine carpentry

Good