Permatrim---thumbs up or thumbs down?

Thumbs down. :thdown
I've had one on my CD16 cruiser for 4 months now and could have gotten the same results from a $35 plastic hydrofoil. Did not help at all with cavitation. Plus, under certain wave conditions, small slow rolls of wake from odd angles, the boat can be violently thrown sideways. Must be the way that it holds the water. Prior to that, I would have bounced across the wake. Now, hang on tight, you could get knocked out. I guess the core problem of my cavitation is the near flat bottom and the prop being too close to the surface. My old boats were serious bottom feeders and never had ride issues.
I still love my CD though. :wink:
 
You may be correct that the small fins will work well on smaller boats. I have used te Dolfins on 12 to 14 foot RIB's very effectively. But the cavitation is a bit puzzling? Did you have cavitation before putting the Permatrim on? The mounting height of the engine is critical--both with and without the Permatrim. I have found the Permatrim to be more for putting the bow down and avoiding the pounding, plus getting the stern up faster, than dealing with problems of cavitation. Cavitation is due to other issues--such as prop size, blade types, clearance of the lower unit, and motor height--as well as the boat's bottom and water flow.

My personal experience with even the smaller fins, is that they improve handling in the situations you describe--but again--I have not owned a 16.
 
You may be correct that the small fins will work well on smaller boats. I have used te Dolfins on 12 to 14 foot RIB's very effectively. But the cavitation is a bit puzzling? Did you have cavitation before putting the Permatrim on? The mounting height of the engine is critical--both with and without the Permatrim. I have found the Permatrim to be more for putting the bow down and avoiding the pounding, plus getting the stern up faster, than dealing with problems of cavitation. Cavitation is due to other issues--such as prop size, blade types, clearance of the lower unit, and motor height--as well as the boat's bottom and water flow.

My personal experience with even the smaller fins, is that they improve handling in the situations you describe--but again--I have not owned a 16.
 
thataway":3e1ray1n said:
You may be correct that the small fins will work well on smaller boats. I have used te Dolfins on 12 to 14 foot RIB's very effectively. But the cavitation is a bit puzzling? Did you have cavitation before putting the Permatrim on? The mounting height of the engine is critical--both with and without the Permatrim. I have found the Permatrim to be more for putting the bow down and avoiding the pounding, plus getting the stern up faster, than dealing with problems of cavitation. Cavitation is due to other issues--such as prop size, blade types, clearance of the lower unit, and motor height--as well as the boat's bottom and water flow.

My personal experience with even the smaller fins, is that they improve handling in the situations you describe--but again--I have not owned a 16.
Click to expand...

My current prop is a 3 blade 11.1 x 13. The previous one was a 3 blade 11.6 x 11.
As far as the motor height it is mounted as low as it can be. You can kind of see it in the picture.

http://www.c-brats.com/albums/album768/ ... .sized.jpg

Also, when comparing the level bottom of the boat to the level of the cavitation plate, the plate is about 1 inch lower. To the best of my knowledge, that is the longest shaft available.
If the water is like glass, no problems. I have cavitation in as little as 3 inch ripples at 13 mph. This can vary due to wind direction, wave direction, or balance of the boat.
 
In following this thread I noted earlier posts mentioning improved maneuverability at slow speeds and even with way on in neutral. I'm just getting used to outboard power (again, after too many years to want to think about), am consistently non-plussed by my inability to steer at very slow speeds, being used to sailboats. Just curious as to whether a concensus exists on the degree to which Permatrims really help in this regard. If a lot they might be worth the price of admission. (I've got trim tabs so presume they wouldn't add a lot in the trim department.)
 
Spike38 on the subject of contolling trim with the permatrim verses the trim tabs for me the permatrim is far superior in that it's much easier to use and the trim is altered much quicker. I use my trim tabs to control side trim. As far as added control at low speeds I do believe the permatrim helps in this department also.
 
I started with Lenco 12x12 tabs. After asking lots of questions and working up the courage to drill 10 holes in my motor, I finally bought and installed a permatrim. I have been very happy with it.

The following is a quote from Les Lampman. He posted this in response to my question about having both trim tabs and a permatrim. This helped move me towards ordering the permatrim.

"I don't see it as being an "either or" situation at all. I'd rather have both options than none and only the tabs if I get one choice but for the price I'd definitely have both."

Rob
 
Spike,

The permatrims definitely allow better steering while gliding thru the water with no power. Like you, I had sailed for years and really felt lost with so little control while gliding/drifting without power on a power boat. Even the TomCat 255, which I assume is more difficult to turn than any of the single hulled C-Dory models, has excellent control with the Perma trims.

I glide down the way and into my slip every time with no power needed since the steering under drift is so pronounced.

John
 
drjohn71a":3vm7cs2t said:
Spike,

The permatrims definitely allow better steering while gliding thru the water with no power. Like you, I had sailed for years and really felt lost with so little control while gliding/drifting without power on a power boat. Even the TomCat 255, which I assume is more difficult to turn than any of the single hulled C-Dory models, has excellent control with the Perma trims.

I glide down the way and into my slip every time with no power needed since the steering under drift is so pronounced.

John
Click to expand...

John-

Have ever driven a jet boat?

Anytime the motor runs, the jet thrusts.

Forward, neutral and reverse are accomplished by a cup diverter:

No diverter= forward.

Diverter fully down, thrust backwards = reverse

Diverter half down, jet stream half and half = neutral (spinning jet stream still rotates boat some)

Come into dock, shut off engine= no thrust, = no steering= no control

Takes some getting used to. You have to learn to drive a boat all over again, pretty much.

Some jet drives (Hamilton) are better than others, and have a little better control.

CW could tell us more about this!

Jet skis are like this, and most of them have NO NEUTRAL OR REVERSE, JUST FORWARD AND IN GEAR!!

Jet boats need bit of a rudder to steer with when he power's off, but a rudder on a jet ski would be very dangerous.

If you've never driven a jet boat, don't just jump into one and expect business as usual! It's like a 5 year old kid thinking because he can ride a tricycle, he can jump into his dad's pickup and go 4-wheeling on the sand dunes!

Permatrims get a lot of their control from their downward side panels that act as rudders, and Permatrims are the best hydrofoils for any of the C-Dorys, as about 15 previous threads have concluded!

Joe. :teeth :thup
 
Yes, Joe, I have had several jet boats. The last one had twin engines, but had absolutely no steering control once the throttle let off. Docking it was like throwing a boulder at the float and crossing your fingers!

As mentioned, I can steer the TomCat adrift without power for over a hundred yards right into the slip. I do it every time I return nowadays... many of my dockmates are amazed you can steer so well without power after having installed the Perma Trims.

I too believe the length and the turned under edges are what works.

John
 
phillipgo":2q5pqzc9 said:
I installed a Permatrim on a 19' Arima,( simalar to the C-Dory). I am very happy with it. Well worth the money.
Click to expand...

Hi Phillip,

I almost bought an Arima- great boats.
I used to take a 17' Sea Ranger out 50+ miles for albacore.
You might want to check out the Arima Owners Group, another great owners group.
 
first of all, welcome Phillip to the C-Brats and thank you for posting about the your experience with the permatrims.

secondly, watch out ya"ll, the OFFICE NAZZI'S are at it again
 
I believe if the permatrim rests at a level equal to the bottom of the boat, cavitation problems will not occur. It is possible that the prop hub is spinning. I'd try another prop before coming to the conclusion that the permatrim is causing problems. I had one on my 22 and with it I was able to raise the motor one hole higher without problems. Ron
 
Welcome Phillip. I agree with you about the Permatrim. I love what it does but equally, what it is-it has no moving parts and it's simple to install. It's elegant, the best $100 item on my boat.
Photo_0002.jpg
 
It really saddens me that such a valuable thread is now likely to be closed because a few people are unable to hold back impulsive comments. For the good of the community, if you have something to prove and feel it best proven through a biting remark, kindly remove the C-Brats.com link from your list of favorites and post your remark somewhere else.

Mike
 
Seabeagle I expect your permatrim may be to low and your cavitation problem may be something related to the prop itself perhaps a spun prop. If you look at the picture of Lizzies permatrim while it't hard to tell at rest the permatrim appears to be pretty high. I had the permatrim on both my previous 16 and my current 22. On the 22 when I first installed it I noticed a slight decrease in top speed and RPM. I raised the motor until the permatrim was parrallel with the bottom of the boat and it was about 1/4 inch above the bottom. In my case this was one hole. This restored my preformance and actually enhanced it from before the permatrim. I never experienced cavitation with either boat. The only adverse change I found was at anchor on the 22 in a two foot wind chop I was hearing a strange poping sound. It turned out to be the permatrim seemed to hold the transom down in the sea and made this wierd poping sound as the waves splashed against the bottom of the swim step. This only happens if conditions are just right. It's hard to do but it may help to operate the boat at WOT and examine the position of the permatrim in relation to the water surface. You don't want it out of the water but as close to the surface as possible.
 
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