I bought some of this tape. It is excellent. A question though, what is the problem with the RV type for marine use?
The quality and consistency can be all over the map so it sort of becomes like going to Vegas. Some may be suitable, while others are just pure junk and may not even be "butyl" at all. The range of product I have seen called "butyl tape" is simply stunning. All the way from excellent quality to stuff that literally melts in water...
I guess it would be the same as asking; "Why can't I just use a polyurethane caulk from Wal*Mart instead of Sikaflex, Boat Life or 3M 4200, its all polyurethane?"
Not all polyurethane sealants are made the same and not all butyl tapes are made the same.
"Butyl tape" is a very, very broad spectrum generic term like "sailboat".. "Why can't I race in the America's cup in my Pearson Triton, it's a sailboat?"
You can't because within the term sailboat there are different types, just as with "butyl tape"..
RV tape is often a gummier, if that is a word, wetter, more solventy, and has more "fillers" in it as opposed to virgin butyl. This can make its ability to stretch, when pressed very thin between a deck and hardware, difficult without a failure. RV tape is generally less dense and less consistent in its extrusion/mix too. This is because it does not have to pass any sort of "industry standard" for quality, consistency, density or other measures.
Much of the tape sold as a butyl tape is not even butyl tape but a "putty tape" and some of it, sold as butyl, may even be water soluble.
While you may get lucky, I have many customers who bough elsewhere first then bought Bed-It Tape and were amazed at the difference.
Here's a few shots of a customers RV tape:
Image courtesy Triton106
This is a high filler content tape very typical of RV tape. Instead of stretching it tears and fails..
This is what Bed-It Tape can do...
And here's a comment about the differences;
Originally Posted by Triton106
I received my order from Maine Sail today for three rolls of Bed-it Tape. I could not wait to see the difference between that and the (brand name removed) butyl tape I ordered from (vendor removed). I cut a 2 inch piece from one of the rolls and stretched it horizontally as far as I could and it clearly is far more stretchy than the (manufacturer removed) tape. I also noticed that the texture of the tape is a lot finer than the other tape.
I am not out to publicly malign other products, just to show there are differences, so have removed the vendor and manufacturer. If you want to try and save money I say go for it, you may get lucky. I like to save where I can too. Bed-It Tape is not the least expensive product you'll find but also not the most but it is a good quality without any guesswork involved.
Hope this helps...