Re: Do I Need an Anti-Cavitation Plate?
After owning several soft-hull inflatables (as opposed to RIBS), I can make the following general comments about them. The hull is not very streamlined and therefore will never run as true as a traditional glass hulled boat. Also, since these boats are so light in weight, when you raise the engine high enough to avoid spray, you often cavitate and experience prop blowout in rough water. It is not uncommon to get the water spray problem you mention even if you have the correct length shaft.
Question ? is the outboard thru-bolted to the transom or simply clamped on a knurled plate with pinch bolts? If it is not thru-bolted, be extremely careful when adding any spacer on top of the transom to raise the engine as the engine can easily come off the transom should you accidentally hit an obstruction underwater. Come to think of it, if it?s thru-bolted, your only option in raising the engine would be to drill additional mounting holes (not a good idea).
There used to be a custom-made adapter sold by a manufacturer which bolted to your transom and then your outboard mounts atop this adapter. As I recall they were made in varying heights (approx -1?-3?). Unfortunately, I cannot recall the company but I learned of them through a RIB forum perhaps 6-8 years ago. You might try to google Inflatable/RIB forums and sift through the results. Sorry I cannot be more specific ? good luck.
