Trim Tabs vs. Interceptors

I "have" a set of Interceptors completed, but waiting to get on a plane from AUS for our Cat C12 715hp powered Tiara 42 Open. The original MI props had some cav burn when I bought the boat used that we've been chasing so finally decided it was time to replace... With the current setup, we were running 28.5-29kts @ 75-80% load, burning 50-52 gal/hr with maybe 30% tab. Once they finally arrive and we're able to splash the boat to test, I'll post our findings.

Max

Apologize for the confusion... I was talking about Veem Interceptor propellers not interceptor tab system. We still have the stock Bennett tabs on the boat.

max

I just noticed in this photo of the latest 100 footer launched by Permare that they installed interceptors rather than trim tabs from the factory, and this thread popped to my mind.

Wondering if anyone had a chance to make any further experiences/comparizons, in the meantime?

Interesting. Lazzara eliminated trim tabs on some of their boats including the 84 i run. Instead there is a 1/4” strip of SS at the edge of the transom where tabs would be. Pretty much a fixed Interceptor. Works very well as the boat pops on plane with almost no bow rise at 1500 rpm and 15.5 kts. Doesn’t seem to create a lot of drag even at high speed. 1950 fast cruise is 26kts...

Trim tabs that extend beyond the transom as opposed to being set into a hull pocket are amplifiers of a following/quartering sea. I like the design of the Interceptor.

Hatteras used to recess the trim tabs in hull pockets. Not sure if they still do, probably not. When I repowered my 53 I removed the originals, closed the pockets and mounted 54x12 on the transom following Bennett’s recommendation. Big difference in running attitude

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True. And you could reduce drag a little.

Wow. My 53c had the pocketed version, and were very rarely used. Had I thought of extending the running surface as you did, I might have given some considerable thought to that...

...I did, however, like them tucked in with the pocket versions when fishing in deep water, not protruding, be it for fish, lines, or wave action.

I was looking thru the file I have on board which includes a detail log starting from day one in March 1970 and covering the first 12-15 years.

In 1971 the original owner had 4” added to the original trim tabs... I was also amazed to see that around the same time they recorded A 17kts top speed with 8V71Ns. Yes naturals. Now the long doesn’t say how it was measured... no GPS back then. Maybe times along a measured mile...

In principle I agree with the objections of Capt J to such solution, but pretty sure it's hard to beat in terms of simplicity and durability!

1/4" is by how much those strips extend under the transom border, I suppose.
Do you possibly know also the other dimensions, like the steel thickness and the total heigth, including the part which is (I guess) bolted to the transom? Besides, how extended are those strips horizontally?

In the above Amer 100', they look wider than you would expect from traditional trim tabs.
Practically as wide as the whole transom - centreline aside.