23DV: 12x24 Tabs vs. Permatrim/Side by Side Comparison

[grouperjim]

Place: Gulf of Mexico
Conditions: 2-3 feet
Boats: 2006 2320 w/12x24 Bennetts/Merc Rev 4 17p
2007 2320 w/Permatrim and factory 12x12 Lencos/ SWS 19p

Both boats with 120 gal fuel, two people onboard, full fishing gear, ice etc. for a 120 mile trip.

A friend of mine with a 2320 has been contemplating larger trim tabs to help control the bow. Instead of opting for the larger tabs, he installed a Permatrim.

We went out tandem on a fishing trip with identical fuel, gear, and people. Both boats were loaded the same as far as CG.

Results: With the Permatrim, my friend's boat easily stayed on plane 20-25 mph even with a 3 bladed prop. Without the Permatrim, is boat fell off plane at 28 mph. My boat with the bigger tabs and Rev 4 of course stays easily on plane 20-25 mph.

Running in the Gulf side by side at 30 mph, the bow of the Permatrim boat actually stayed down and pitched less than my boat no matter how I adjusted my tabs or engine. Do to wave spacing, for me, 30 mph was the limit as far as beginning to pound somewhat. The Permatrim boat was able to cruise easily at 35 mph without pounding. The engine was trimmed up 2 bars with no tabs.

Analysis: I was very surprised and impressed with the performance of the Permatrim--especially since it is only a $136 modification. Essentially this thing is nothing more than a fixed trim tab that is bolted to the A/V plate. Because the Permatrim is mounted an additional five feet further aft of the traditional trim tab, the pitch axis is extended significantly giving the boat the feel and ride of a much longer boat, thus allowing the hull to span the waves in certain spacing resulting in less pitching of the bow which was the case the day we went out.

An interesting experience that I wanted to share. I am considering one for my boat. Anyone else out there have any experiences good or bad with a Permatrim?

Almost forgot-- the fishing report. Gas Pipeline, 135 ft, 14 lb Mutton Snapper was the highlight of trip. Also some barely legal Red Grouper and some med/small mangos. A nice Wahoo cruised the stern but no flat lines out so we missed him.

jim

 

[Porkchunker]

I was in a similar situation, shortly after I purchased my boat. Didn't want to expend the $$$ for larger tabs, and decided to try an experiment with some similar plates (from Cobra) on my twin F-115s. They defiantly solved the problem at a much cheaper cost.

There is a thread in the projects forum entitled "Show us your doel-fins" (or something like that. I'll see if I can find it and post the link here.

I don't understand why the motor manufacturers don't put larger anti-cavitation plates on their motors in the first place.

Dave

aka

 

[Porkchunker]

Found this, but it isn't the right thread:

http://classicparker.com/phpBB2/viewtop ... ht=doelfin

Still looking...maybe it wasn't in the projects forum...can't remember that far back.

Dave

aka

 

[Porkchunker]

Here it is

http://classicparker.com/phpBB2/viewtop ... ight=cobra

Dave

aka

 

[Outta Here]

How much top end speed did the permatrim scrub off? From my experience w/23DVCC in SE NC, we are constantly trimming left and right for people moving around in boat, can't do with any of the "add-on" fins. Ever have to run a course perpendicular to wind for an hour or so? Boat requires constant steering correction only trim tabs will fix (not to mention having to put up w/boat leaning to one side). Should my steering go out, I'm pretty sure I can steer boat in with tabs.

I cannot think of one boat builder or motor manufacturer who offers any of the "fins" standard or optional. Gotta be a reason. Real, hydraulic trim tabs of proper size might be the "cheapest", best value addition to any salt boat.

 

[captbone]

While Doel fins or Permatrim cant replace trim tabs, they certainly help the running conditions of heavy, single engine boats.

The trim tabs can be adjusted for ever changing conditions (people, fuel sea conditions).

The doel fins and permatrim dont do that, they just lift the stern further back than trim tabs and drop the bow better. That all they can be expected to do. Bring the bow down and lift the stern while plaining off. This is a huge help because in a chop, they drop the bow better than anything else.

Boat builders will NEVER consider adding them to a new boat because that is the same as saying, we didnt design the boat to ride correctly so we added these.

I have used these in the past with great results. They bring the stern up alot faster for planing off and allow us to stay on a plane at lower speeds.

The best part, is you just have to trim up to negate them and then it is back to normal.

 

[grouperjim]

Permatrim boat was getting 2.6 mpg at 35. I was getting 2.4 mpg at 30 mph, which is the difference between 17p and the 19p props. The advantage is being able to run the 19p (better mid-range fuel economy) and also being able to plane at lower speeds. Don't know about top end. Top end doesn't really matter to me.

jim

 

[TheOtherLine]

The advantage is being able to run the 19p (better mid-range fuel economy) and also being able to plane at lower speeds.

Jim, not sure what you are suggesting. Are you thinking you would have been better of with the 19p instead of the merc 4x17?

 

[TheOtherLine]

Did I not read, somewhere in these posts, that someone had some engine problems as a direct result of using these "fins"?

 

[grouperjim]

Not really suggesting anything. I do like the 15.25x19 3 blade for fuel economy, but switched to the rev 4 because not staying on plane 20-25 was not an option. If I can find a way to plane at lower speeds AND get the 3 blade mid-range economy then that it something to think about. So far I have not yet discovered any downside to the Permatrim. And you know there is always a downside to anything you modify on a boat. I just don't know what that is yet.

jim

 

[SIM]

How much top end speed did the permatrim scrub off? From my experience w/23DVCC in SE NC, we are constantly trimming left and right for people moving around in boat, can't do with any of the "add-on" fins. Ever have to run a course perpendicular to wind for an hour or so? Boat requires constant steering correction only trim tabs will fix (not to mention having to put up w/boat leaning to one side). Should my steering go out, I'm pretty sure I can steer boat in with tabs.

I cannot think of one boat builder or motor manufacturer who offers any of the "fins" standard or optional. Gotta be a reason. Real, hydraulic trim tabs of proper size might be the "cheapest", best value addition to any salt boat.

Fish,

Glacier Bay is the only boat company that I am aware of that ships there boats with any type of fins installed. My biggest Permatrim customers by boat manufactuer are by far C-Dory(cats and mono's) followed by Glacier Bay and Scout. Parkers rank up there too.

When I got to work I had 8 email requests for quotes on Permatrims from Parker owners, so I figured a discussion must be going on a Classic Parker and obviously their was. I normally check this site daily and somehow missed this one.

Are Permatrims for everyone? No. There will always be sceptisim with any bolted on item. But then again the same comments can be said about "real" trim tabs when you think about it. How come boat manufacturers do design there hulls better so they do not need trim tabs? No one thinks twice about drilling 21 holes in their transom fiberglass and inner supporting wood to gain the benefits of trim tabs. But drill a hole in your AV plate? Better call in the president of Yamaha to get approval! lol jk

Bracketed powered boats have the greatest possibility of loosing a small amount of speed at WOT with a Permatrim since the engines are set farther back off the transom and therefore the gear case's are in more "open" water. With transom mounted engines, if you loose WOT speed, just raise the engine up a hole(you most likely are to low anyways). Most of the time you can expect small WOT speed gains because you are able to trim the engine farther up and still have the prop stay hooked up with a Perm installed.

Andy

 

[Megabyte]

Thanks Andy. Good to see you checking in here. :wink:

 

[grouperjim]

Fish:

If I install a Perma, I'll be switching back to the 19p wheel, so for me, my top end will increase from 44 (17p) to 47/48 mph which is my WOT with a 19p.

Having traditional trim tabs are still important for the reasons you stated, but I think the unique advantage of the Perma is that the Perma actually lengthens the pitch axis of the boat which delivers a smoother ride in certain sea conditions. This is something that a regular tab is not designed to do.

I've also looked into the Cobra plate which is effective too, but the Perma extends further aft of the prop which is where it is most effective. I have say I like the looks of the Cobra over the Perma but I'll take "function" over "form" any day.

jim

 

[Porkchunker]

The plates do not take the place of the tabs when trimming from side to side. In my case, they overcome the 800+ lbs of motor on the bracket that make my boat ass-heavy. By adding the lift of the plates, the tabs are much more sensitive, and can accomplish their intended use. Without the plates, the tabs were woefully inadequate to do much more than plow the water and consume fuel.

 

[JC]

By adding the lift of the plates, the tabs are much more sensitive, and can accomplish their intended use.

Ditto..... I have a "Cobra Pro Stabilizer" on my 2120. The plate provides additional lifting action relieving force on the Trim Tabs allowing them to control roll and pitch more effectively.

 

[Outta Here]

Thanks Andy. Good to see you checking in here. :wink:

Yep...My Rev 4 and misc parts all come from SIM. Can't beat price or service. :wink:

If ya gotta have some fins, I highly reccomend Andy, or..........

Cadillac 8)

 

[Mokee]

Ditto on Fish Factory's SIM endorsement.

I've got a Permatrim from Andy installed on my 150 HPDI.

 

[MaxOut]

Can somebody post a picture of these Permatrim's Installed? I would like to see them.

Thanks! :lol:

 

[grouperjim]

Some here.


http://www.shipyardisland.com/images/Pe ... 20Rev1.pdf

jim

 

[Wicho]

Fish:

If I install a Perma, I'll be switching back to the 19p wheel, so for me, my top end will increase from 44 (17p) to 47/48 mph which is my WOT with a 19p.
jim

Jim...
And you'll always have an appreciative second hand prop buyer for that merc rev 4!!!