For years I did not believe about the benifits of fitting hydros. A friend of mine with a 5.5m Humber and a 100 yam 4 stroke swears by them and has fitted them to every boat he had owned, I used to think they were crap. My previous Redbay (Jellys now) was the first inboard Rhib that I have had. I was not very happy in her trimming ability as what ever angle you tried to trim her to is made very little difference to the ride of the boat, so I bit the bullet and after much slagging off fitted a set.........what a difference I could now trim the boat to suit the sea conditions, the way I like them. When I was over in Redbay picking up my new boat I noticed that some of their customers boats have them fitted, even in twin setups, however my current boat does not require them as she will trim away quite happily.
But who knows I might just fit them next time shes out of the water.
I'm no scientist but all that I can say is that they worked for me and did exaclty what they said on the tin!!
Hard or Soft it's never BIG enough