Trim Tabs and/or Permatrims on a TC 255?

Captains Cat

There are lots of 255's out there now, what is the concensus on tabs? Do many of you have trim tabs on there and are they considered useful? I know Dr John has permatrims, is that enough?

I'm considering a 255 at this point. Captain's Choice would be for sale, probably in the spring, got some things I want to complete on her before that though...

Charlie

Discovery · Posted: Thu Sep 06, 2007 9:51 am Post subject:

Don't think there's room for trim tabs on a TC255. We have Honda SST Hydrofoils on Discovery. Others have Permatrims.

drjohn71a · Posted: Thu Sep 06, 2007 10:20 am Post subject:

With my experience using trim tabs on other boats vs. Permatrims on the TomCat, the Permatrims offer much more robust control than trim tabs. In fact, just leaving the Permatrims set level, the boat's performance is greatly improved.

An extra bonus of the Perma-Trims is that, when going slowly, as in docking, you can still have effective steerage when the engines are in neutral. Somewhat like a sailboat's rudder effect.

The unique water dynamics from the aft edge of the narrow hulls to the the raised, set back outboards makes installation of a large enough trim tab difficult and I think the performance would be hampered by doing so.

Also, why put holes into the cored hull when greater control is possible with Permatrims or equivalent?

Heading into rough seas, you can force the bow down to allow greater speeds without the bow jumping and airborne episodes - a great comfort for the trip home after hours in rough seas.

I have never needed the total range of control available with the Permatrims. The slightest touch on the tilt control makes significant changes.

John

Captains Cat · Posted: Thu Sep 06, 2007 3:15 pm Post subject:

Thanks John et al.... Just looked at the boat and I agree, I don't think there's room. This boat has Suzi 115's on it, a little small but the current owner says it'll do 40mph lightly loaded and in a smooth sea and that's plenty fast for me! They should be somewhat lighter than a bigger engine too. I think it's hull #16 so I need to look closely for some of the early problems you folks have had....

The macerator pumps for the fish boxes aren't even fastened to the transom, they are hanging on their inlet and outlet hoses.... I guess I should be glad they didn't screw them in!

Charlie

thataway · Posted: Thu Sep 06, 2007 10:23 pm Post subject:

There is no room for trim tabs. If you want to plane the boat at lower speeds, then the Permatrim (or other tabs help). Otherwise, I would run the boat without first.

I added Permatrims, and I don't see a great deal of difference. I don't think that the rudder effect is any different--it was present before. What I have noticed is a huge quarter wave at 8 to 10 knots. I can plane the boat down to 11 knots, but not below.

The Permatrims have not helped, in fact may have hindered the fuel consumption.. Top speed may be slightly less--but again, the boat has been slightly more heavily loaded, so it is difficult to tell.

I think that the 115's may be fine for the very light load--and if you only take day trips, with light loads, they may be OK--but the engine displacement is 30% less than the 150's. If you want to do serious cruising, you may want the bigger engines. I don't think you will get any better mileage at the same speed, and you will be really working the engines. The 115's were well suited to the TC 24. But that was a considerably lighter boat. Also this boat has older 115's--as I recollect he had the same engines on a pirsuit before the Tom Cat 255.