Which trim tabs?

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artwhitting

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I have a 1990 Seafarer with a bracketed 225yami 4stroke. I got her in April with a 225ox66. Upgraded to the 4stroke and she's butt heavy.
I would like to get on plane at slower speeds so I'm thinking trim tabs. After reading the Bennet site it looks like 12x9's or 12x12's.

Any recommendations?

thanks

Art
 
With trim tabs, regardless of brand, ALWAYS go for wider ('span' across the hull) tabs versus 'chord' (depth or projection off the hull). All tabs work by creating lift, which also creates drag. You will get the same lift by deploying wider tabs of same surface area than deeper ones. I'd state unequivocally to go with 18" span by 9" tabs, or 24" wides ones if you can.

If Bennett, and IMHO there's no other brand to even consider, contact Tom McGow, aka Tabman. I'd retrofit a tab in place that might be able to use your existing actuator.

FYI, I run fuel computers on my boat and in side-by-side tests of same hull with same motor, I was able to achieve a 20% or greater fuel economy using my 24x9 Bennett tabs versus the other boat with Lenco 18x12 tabs. Excess tab lowering KILLS fuel economy.

If you saw I just bought a new-to-me GW, it has the Navman 2-1/8" in-dash readout fuel computer. Using tabs to 2-3-seconds 'down' adds 10% of more fuel economy. Some hulls just ride best at a certain attitude. This makes the Bennett auto-tab leveler system (maintains trim regardless of loading & conditions) almost a no brainer!

Well, not 'ride' per se, but fuel economy wise that is :D. In heavy seas or a chop, one may clearly need to drop the bow to get the best 'felt' ride. But even there, wider tabs make more sense and are faster to respond.
 
Thanks for the info.

My concern with the Seafarer is the 'raised floor on each side of the transom. I'm not sure of the length, but hole needed to be cut thru the transome could be under the sub floor. I'll know better ina few days.

Also thanks for the larger span theory, I was dead wrong in my assumption the a longer chord would be better.

cheers
 
Art,

Dale H is 100% on target.

I am working with an owner of another brand of boat on another forum who added a bracket and a 4 stroke. The Trim Tabs that were on the boat with the original transom mounted 2 stroke worked great, but now with the added weight of the 4 stroke and with the bracket the center of balance has shifted considerably aft and the old Tabs aren't cutting it.

If you get a chance to post a picture of your transom I would be delighted to give some input where the actuators (rams) will land. We have a few options we can offer if they land below the subfloor.

Tom McGow
Bennett Marine
 
I agree with Daleh and Tom . I have a 228 seafarer w/ f 250. It came with the stock tabs (9x12 ?) and I am also looking to go bigger as response time lags a lot and as Tom says , these tabs are just "just not cutting it" either...probably because of the weight. Go with the biggest tabs that you can. Also, my engine came rigged 3rd hole from the bottom. Anti vent plate was well below water when running and had some porpoising. I recently raised the motor one notch and didnt really see much difference in speed etc,except porpoising actually seems worse, which is unusual. Im hoping that the bigger tabs will rectify that somewhat. That f 250 on a bracket is awfully heavy for this boat and I think that they had to do some creative stuff to make it work.
 
Thanks for the input. I was about to buy the 12x12, but your info and the info on Bennet looks like the 18x9 are the best fit.
Looks like the acuator needs to be about 10 inches minimum.
----talked to Bennet and they recommended the 18x12's and the acuator is 13-3/4 inches so I should be good.
18x12's or 18x9's?
Do you think the tabs will interfere with the transducer?

mocktab1.JPG
 
I have a 1990 228 with F225. My lenco tabs are electric and return to the up position when the ignition is turned off. I was told they are a better buy than bennett, although Im sure some will disagree.
 
Thanks for the info NJ-John. What size Lenco did you buy?
 
Art,

If it were my boat I would go with the 18 x 12. They will give you the most amount of lift and let you hold the bow down at lower speeds (a good thing with the bracket and 4 stroke).

I am not sure if you were mocking up the actuator (ram) with the tape or just holding the "tab" up. The actuator mounts 8-5/8" from the transom and the standard length of it is 13-3/4".

Here is a drawing so you can workout the geometry:
stdactheight1.jpg


There are options to make the actuator shorter if need be, let me know what you come up with.

It looks like there is enough space between the Trim Tab and the transducer to prevent interference.

Bennett also has an option for Auto Tab Retraction when you switch off the ignition (In fact we invented it :D )

Tom McGow
Bennett Marine
 
Thanks for all the help. I'm going with the 18x12's

My off-plane fuel consumption equals my top end consumption. I'm hoping this addition will change that.

Saludos

Art
 
Purchased the 18x12 Bennett and finally installed them. Since I had never done it before, I had to wait until I could get help creating the negative angle.

Bad:
1. The wires nounted on top of pump are unprotected and easy to chaff while determining the clearance.
2. The pump mounting bracket should allow for floor mounts, but I guess there's a reason for it not being there.
3. The fill hole should be angled differntly for ease of fill.
4. The accuator pipe was almost too short and may change to the longer during my next maintenance window.

Good:
1. Bennett components feel and look great. Well built and good quality.
2. After diving in, it was a straightforward install.
3. Not having to bleed the pump!!! This was great!

Test:
Launched in the dark to look for YT. Cruising through the bay in greasy flat water at 10 mph, fully loaded with gear. The normal squatting was not there. Already she felt different. Before, problem area was from 10-16 mph offplane. Now she sets high and the best part is no squatting when I throttle down, no wake coming high o the cowling. Fuel monitoring shows an improvement when 12-18mph would be at 9-11gph to an average of 7gph.

Conclusion:
These tabs just what I needed, her whole attitude was different and I'm very very happy. I will upgrade the switch to show position, but not after I try to learn by feel first.

Thanks for all the info.

Saludos
 
Art,

Thanks for posting your impressions regarding the installation, I am forwarding it to a few people at the factory as well as my notes (there are some things that need to be added to the instructions).

Can you please expand on what you mean by the wires on top of the pump being easy to chafe when determining clearance? Do you mean when the protective cover is off?

We do have a 90 degree bracket for floor mounting the pump (I think that needs to be added to the instructions).

Point taken on the filler.

We also have different lengths of pipe nipples available (should also be added to the instructions). The standard is 3" and fits most transoms, if you like I would be happy to send you 3-1/2" or 4" nipples at no charge, send your address to me in a private message.

I am delighted to hear that you found the installation to be straight forward and that you are pleased with the results.

Tom McGow
Bennett Marine
 
Tabman said:
Art,
Can you please expand on what you mean by the wires on top of the pump being easy to chafe when determining clearance? Do you mean when the protective cover is off?
Click to expand...

Hi Tom;

thanks for your support. While trying to determine the place for the pump to install, yes I removed the protective cover. While fitting the pump into the side wall bracket, without the protective cover it banged the wire mounted into the ferrite bead resistor thingy. This was a totally a user error. If this is a common problem, then maybe a change is warranted - otherwise I should be more careful.

I'm definetly interested in the nipples and side mount. I will pm you.

Thanks for the rec on the 18x12's. My outboard guy show them yesterday and agreed that those are the size I needed.

cheers
Art
 
Thanks Art!

Shoot me a PM when you want the mount and nipples.

Tom
 
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