Permatrim

[Captains Cat]

[Will-C]

Charlie,
Anytime but we only carry those little 8 oz cans of beer to save weight.
D.D.

[jlastofka]

Well, I couldn't wait to do a test, so here I am on Mission Bay near San Diego with a moderately loaded boat, somewhat less than a week's worth of stuff but not real light. The boat does well without trim tabs now that the heavy kicker's in the garage. It still likes full down trim on the engine, though.

I guess I'll spend the night, watch Sea World's fireworks and be a little late for work in the morning…

-Jeff

[Spike]

Charlie
115 hp Yamahas do not have a restrictor pin set up, hydraulic from stop to stop. I really dont run all that heavy and try to shift as much weight as I can forward. Just dont think they are worth the money, but will keep it on as I now have 8 nice little holes in my cavition plate

[thataway]

We had no trim tabs or Permatrim on the C Dory 22. The boat ran level with out, but there would have been an advantage to get the bow down in chop. The 25 already had trim tabs, and I ran it for a season without the Permatrim. The permatrim did improve the ride into chop, and gave use faster on a plane, and a better top speed when loaded, on an underpowered boat (Honda 135).

There was no adverse affect going down wind/seas--including severe conditions--as long as the boat was trimmed properly. If the bow had been trimmed down, then there would have been bow steering and some potential issues.

[Montana Kev]

Our Permatrim on the 22 with Honda 90 puts up a lot of side spray when we drop the motor down below halfway (as per the trim gage). Is the side spray normal?

Kevin

[texasair]

For the Brats that need to get the bow down, try transom wedges.
Gives you 5 degrees more down trim with less drag than tabs or a permatrim.
Have used them with great success for decades on all sorts of boats.

Currently have one on my 22, as well as a permatrim, no trim tabs.

We handle the side to side trim with load placement.

[Hunkydory]

Have the Honda twin forty's and for eight years have used just the bennett trim tabs with very satisfactory results, except on the Alaska cruises with our extreme weight. Then even with the trim tabs fully extended & shifting to the sleeping area much of the stuff during the day felt would improve performance, milage, & ride if the bow could be lowered, so decided to install Permatrims before going to Yellowstone this year. Won't know until next years Southeast Alaska cruise how well the combination works under extreme boat loading, but am overall pleased with them now. With full fuel & water tanks & the boat medium heavy with gear found best performance to be to have the Permatrims aligned with bottom of the transom & 40 percent on the Bennent tabs at 15 mph. Of course at higher or lower speeds the optimum percentage of trim would change, but what remained constant was performance was always best if the Permatrims remained aligned with the transom & trim made with the Bennets. When I wanted the bow down more going into the chop could really then force the bow down much better then ever before using both the Permatrims & Bennent tabs making for the smoothest ride into heavy chop we've experienced yet. The ability to have more combinations of trim & just plain more trim available is definitely a plus. They also solved the problem with prop ventilation I have had at times when trimming into chop or with moderate to heavy load. Would under these conditions in the past have to trim the motors way down along with the the trim tabs even further reducing performance efficiency to stop the ventilation.

Now the negative. The Permatrims reduced my WOT rpm just enough (from 5100 to 4900) that prop changes had to be made to run at the 8000 feet elevation of Yellowstone Lake. Ended up with new stainless 11 7/8 X 10 pitch that max out now at 5450 rpm (Honda 40 likes 5000 to 6000) at 21 mph.

Jay

[Wefings]

Dave I cant resist . It sounds like you are heavily loaded in a life style manor as well as shifty. I would advise anyone to use trim tabs first and to analyze the need for Permatrim later . Wedges are a good addition to stern heavy boats . They will bring the bow down in a geometric or balanced manor ,have no permanent downside and retain the tabs available for you for major leveling and serious bow stuffing . Permatrims are a necessity on 16s , but from all I have absorbed from this site ,the jury is still out on most models . Once you drill those holes , you just want it to be the right thing........
Marc

[tpbrady]

Marc,

Do you have a picture of what a stern wedge looks like?

[Wefings]

Look at these from Bob's Machine shop. 2 different styles . T&H Marine makes them too .
Marc

[Chester]

Our 22 came with twin 40's, permatrims and stern wedges. The pins that limit the down trim are in the second hole from the bottom which seems to negate the wedges. I assumed the dealer set it up that way and knew what they were doing. I wonder if the pins are relocated to the bottom hole the permatrims could be bent or damaged though I can't imagine using that much downtrim at planing speed. Quite likely I'm not getting full benefit of them due to ignorance.

[tpbrady]

Marc,

Thanks for the link. Now I understand. I am not sure of the transom wedge would be any better or worse than a Permatrim. Somebody really needs to do some detailed testing of both to see if a wedge increasing the angle of the ventilation plate in the water coupled with a propeller thrust angle that is not in line with the motion of the boat raises the stern more with less drag than a Permatrim.

My experience with a Permatrim on my 25 seems to show the best fuel flow numbers at any speed are obtained by a combination of trim tabs to push the stern up/bow down, with the motor trimmed up to be parallel to the direction of travel. The effect of the Permatrim seems to be to keep the stern a little higher. I generally run with the motor in one position only (trimmed up toward a 0 angle) unless more down trim is needed due to sea conditions. As speed increases, I back off on the trim tabs such that at 25 mph, I have about 1/3 to 1/4 tab down and at 28 mph, I have them completely retracted. At 12 mph they are full down.

I tried using using the Permatrim for more bow down with less trim tabs and consistently the trim tab adjustment resulted in the lowest fuel flow at any given speed. If I could design it, I would look at a fixed transom flap between the trim tabs with a notch for the motor as the best approach since it would offer the lowest drag.

[localboy]

I must confess, I don't know which way to go. I've been going back and forth on this issue; the cost, the holes, is it "worth" it? I can't judge based on fuel consumption numbers as we do not have a fuel use meter.

I usually run nearly full trim tabs down as the boat always seems "ass" heavy to me and we do not travel "heavy". IMO with the water tank in the lower bilge (2007) it only adds to the stern heavy attitude. We're in the process of adding a 9.8 kicker, so that will be ANOTHER ~100 lbs astern. Guess I'll see how it handles once that's added and go from there.

[Captains Cat]

For goodness sakes, bite the bullet (sorry for the metaphor) and do it. You won't be sorry. It's the price of about 15 McDonalds meals... And you get to keep it!

Charlie