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Where to mount trim tabs 22ft cruiser

 
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rock knocker



Joined: 29 Sep 2016
Posts: 24
City/Region: Georgetown
State or Province: CA
PostPosted: Fri Nov 30, 2018 10:51 pm    Post subject: Where to mount trim tabs 22ft cruiser Reply with quote

Have some basic trim tabs id like to mount on my 22ft cruiser. Can someone post pics on where yours are mounted or would you recommend the outboard tail fins? Ive got twin 40hp yamahas. Thanks in advance.
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hardee



Joined: 30 Oct 2006
Posts: 9425
City/Region: Sequim
State or Province: WA
C-Dory Year: 2005
C-Dory Model: 22 Cruiser
Vessel Name: Sleepy-C
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PostPosted: Sat Dec 01, 2018 2:42 am    Post subject: Reply with quote

Not sure what you mean by "basic" trim tabs but here is how to get plenty of Trim tab info.


I just entered this into C-BRAT Search box :

“ trim AND tabs AND mounting” and got 66 threads.

As you look down the list you can prioritize from most interesting (helpful) to less.


Water intrusion from trim tab mounting?

Transom Drilling

Benett trim tabs

trim tab help/advice

Another new trimtab believer

My Bennett Sport tabs arrived today! Now what?

That is a few of the listings. Copy and paste my query without the quotation marks into the search box, and then click the “All” button and go from there.

Harvey
SleepyC Moon


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thataway



Joined: 02 Nov 2003
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City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
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PostPosted: Sat Dec 01, 2018 8:07 am    Post subject: Reply with quote

Quote:
outboard tail fins?
These are called hydrofoils--and the brand most often used by C Dory's are the metal Permatrims. There is a good reason that they are used. They give more lift, control and less resistance. The cheaper plastic foils will work-but to a lesser degree.

For twin 40's I would go with the Permatrims. With twin engines that may be all that is needed. For single engines, I strongly recommend both a adjustable trim tabs and a Permatrims.

If you mean by "basic trim tab" the ones which do not require adjustment (hydraulic or electric)--also called "Smart Tabs" or "smart trim tabs". I would strongly advise agains these for a C Dory 22. You want to be able to adjust the tabs for the conditions. If the tab is put down partly, it might help the boat get on a plane faster, but it may be dangerous when you are going down wind and waves.

Try the Permatrims first.

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Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
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DavidM



Joined: 24 Dec 2017
Posts: 92
City/Region: Punta Gorda
State or Province: FL
C-Dory Year: 2006
C-Dory Model: 22 Cruiser
PostPosted: Sat Dec 01, 2018 9:11 am    Post subject: Trim tabs, Permatrim and outboard trim Reply with quote

I am a little confused about the applicability of these three to a single outboard powered C-Dory:

1. Use of adjustable transom mounted trim tabs

2. Installation of a Permatrim which is a hydrofoil that mounts to the outboard.

3. Using the outboard's built in trim capability.

It seems that if the boat is has proper weight distribution fore and aft, then the outboard's trim capability should be able to dial the boat to match conditions.

If you have to move the outboard with its trim too much and you are losing thrust as a result then the Permatrim will enhance the outboard trim and let you get what you want without too much outboard trim.

It seems that adjustable trim tabs have no value on an outboard powered boat as the foregoing will do it much better.

Thoughts?

David
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A Fishin C



Joined: 02 Dec 2008
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City/Region: Victoria
State or Province: BC
C-Dory Year: 1989
C-Dory Model: 22 Cruiser
Vessel Name: Nootka Rose
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PostPosted: Sat Dec 01, 2018 10:02 am    Post subject: Reply with quote

I have both permatrim and trim tabs. I think the 22 needs both with a single out board.

Permatrim on the single outboard gets the bow down or up.
Trim tabs adjusts side to side, not too efficient at getting the bow way down.

My previous 22 only had trim tabs. Not enough to get the bow down far enough when riding into a chop.

and to the original question, see my pics for where to install trim tabs.

DavidM, do you have a 22 C-Dory?

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rbfconstruction



Joined: 19 Sep 2017
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PostPosted: Sat Dec 01, 2018 10:39 am    Post subject: where to mount trim tabs Reply with quote

I have both (trim tabs and hydrofoil)
I was anxious so I picked up a plastic one at west marine. It was very in expensive, slid onto the outboard without any drilling (just a set screw) and made my 19 footer a new boat. It got rid of the hard slap in rough chop and gets on plane, stays on plane faster. I. love love love it !!!!!!
As for the trim tabs, I mostly use them when I am weighted to one side or the other by passengers or load or current.

Richard

Im probably wrong but it felt that the 75 yammi was working too hard with the trim tabs for getting on plane
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thataway



Joined: 02 Nov 2003
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PostPosted: Sat Dec 01, 2018 3:17 pm    Post subject: Re: Trim tabs, Permatrim and outboard trim Reply with quote

DavidM wrote:
I am a little confused about the applicability of these three to a single outboard powered C-Dory:

1. Use of adjustable transom mounted trim tabs

2. Installation of a Permatrim which is a hydrofoil that mounts to the outboard.

3. Using the outboard's built in trim capability.

It seems that if the boat is has proper weight distribution fore and aft, then the outboard's trim capability should be able to dial the boat to match conditions.

If you have to move the outboard with its trim too much and you are losing thrust as a result then the Permatrim will enhance the outboard trim and let you get what you want without too much outboard trim.

It seems that adjustable trim tabs have no value on an outboard powered boat as the foregoing will do it much better.

Thoughts?

David


David M--I have been thru this--I bought my first C Dory 22 with a 90 hp Evinrude in 2002. My neighbor had a 22 at the time. I had neither trim tabs or a Permatrims. The boat was OK--but not what I expected for the "ride" and performance. My neighbor was adding trim tabs, so I became curious. Also in 2007 replaced that 22 with a 25 which had trim tabs--both kept on the West Coast. Because that boat had only the 130 Honda--(block same as the 115 hp) it was under powered--and so I added the Permatrim to help get the boat on a plane. It made a lot of difference in the ride.

The transom mounted trim tabs give balance right to left--and thus you can have a level ride. But they do not give enough "bow down" to push the boat thru the chop. By adding the Permatrims--the bow is pushed down, and the chop hits the "V" part of the hull, rather than flat part aft. The Permatrim increases the outboards ability to put the bow up or down.

Now, if you shift weight--lets say 100 feet of anchor chain--as one East Coast dealer did regularly--then the bow may be down too much when going down wind and waves--leading to dangerous bow steering and broach at the worse--poor handling at best. Granted the boats were first made more as day fishing boats--with a 70 hp outboard--and flat bottom with moderate rocker (up to 1987--when the V and some variable dead rise were added.

You will find that the "thrust" --which is important--pretty much aligns with the attitude of the motor--even with the trim tab--in fact in some cases it improves that part of the equation.

The trim tabs are side to side--For example, if Marie wants to go out of the cabin and sit on the starboard side of the cabin--and we are at a planing speed, she will tell me--and I will compensate to keep the boat level and ride comfortable, with the trim tabs.

If you don't have the tabs and Permatrim you are not getting the maximum out of your boat.
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DavidM



Joined: 24 Dec 2017
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City/Region: Punta Gorda
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C-Dory Year: 2006
C-Dory Model: 22 Cruiser
PostPosted: Sat Dec 01, 2018 3:58 pm    Post subject: Reply with quote

Ok, I hadn't thought about the side to side trim for which the transom mounted adjustable trim tabs are the only way to do that.

So it seems that all that have responded so far support my assumption that a Permatrim enhances the outboards up or down trim and it seems that the C-Dory 22 needs more down trim heading into a chop than is available with a non modified outboard.

FWIW I do not have a C-Dory. I have a new Alas Pompano 23, a similar purpose boat but with a downeaster style hull. I ran into 2' chop a week or so ago and played with the outboard trim. Actually a little bow up trim improved speed and stability into the chop. Too much bow up caused cavitation so I lowered the bow a bit below that point. But this boat has a shallow full keel so it handles differently than a C-Dory.

David
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