M80's or M120's

[cSickNick]

Well, i need some more expert advice on my next project, this time on tabs.

I am thinking Bennett's M80's because of the fit inside the 1st step.

Because i have a 20' Seafari, 115HP OB(weight/min HP), would i be better off with the larger M120's tabs?

Thanks again! .... Nick

[timd]

I chose the M80s, mostly because they fit better between the lifting strakes. They provide more than enough lift, and I would venture that the stern of my boat is heavier with a V6 on it.

[JohnS]

Nick,
I had the 120's on my 20 MA. My thought is this
and nothing more. If you need lift, and you go toooooo small, what is the purpose? If you go a bit bigger, and you really didn't need it, what is the difference? None that I can see other then you will plane quicker with the bigger tabs than you will with the smaller ones and you will not plane quick enough if the tabs are undersize. In a case such as this, a little bigger will never hurt and the cost difference is almost nill.

Just my opinion. Why not call Bennett and ask them? They are very knowledgable and have always been extremely helpful when I have called them on anything.

John

[PipeDreamsMarine]

Nick.. Do you have tilt and trim on your motor.. if so then your main use for the tabs is to control list. The 80's will work fine, place them outboard as far as you can. The bigger is better works fine for bigger boats with out tilt and trim because you must over come the forces of the hull and motor load. ..Kick it under, kick it the a$$ and trim her up!!

[JohnS]

Nick,
Go here and then make your decision...

http://www.bennetttrimtabs.com/size1.htm

[JohnS]

Don,
I agree with you however, if Nick EVER needs to get on plane in some shallow waters, such as my case many times, the larger tabs will give that extra lift and allow him to do so. Each boat is different but, I have used a 20SF with the smaller tabs and the 20MA that I had with the larger tabs. I could get on plane in about 2.5 feet of water. In his, I need about an extra foot of water....

John

[cSickNick]

Guy's thanks for the info so far.

I planned to call or email Bennett, but i was curious on what info people would have on using the M80's or M120's.

I read the specs prior on Bennetts site and both are made for a 20' boat.

Having no experience with trim tab's, i assume they would help my current ride. Basically i have to ride in a "squat" position to cut through some good chop. If i trim up the motor to plane, it gradually picks up too much speed to be comfortable in these conditions and then starts to "crash" through waves. I then back off a little, and it falls quickly back to a "squat", which is more comfortable but waves tend to "slap" under the bow.

So ..... am i missing something .... or is the tab's the way to fix a "squat/crash/slap" ride!

- Nick

[AlexT]

Bennett is going to agree that there is no harm and some benefits to going with the larger tabs, for all the reason listed above. For comparison sake, I have a 18' Parker which is a heavy boat at 1900 lbs. w/o motor, and Bennett suggest the 120s. Because my deadrise is straight and space along the transom was not an issue, I opted for the 18"x9" standard tabs, which provide more control.

What the tabs will do is allow you to go faster in the chop and keep the bow down so the sharp forefoot cleaves the waves. How fast you actually go, or if you get up on plane, is a function of the seas at hand and what you consider comfortable.

[cSickNick]

Guys,

I installed the M120's as Bennett's Tom McGow recommended. The ride is now sweetened!

Here is some of the info from our offline chat. Tom was a big help!

Thanks again Nick

******

-----Original Message-----

Nick,

Actually there are no instructions specific to the stepped hull on your
SeaCraft. There just aren’t that many boats like that out there like
them! As you may know I am a Classic SeaCraft fan and Like the hull very much!

I would split the difference with the Tab edge about 1-1/2" from the chin and about 1/2" into the first step.

The shorter actuators com standard in the M120 their overall length is
11-1/2" and they require about 10" vertical height on the transom,
perpendicular to the deadrise.

Yes a waterproof Rocker Switch is in the kit.

I hope this helps,

Tom

-----Original Message-----

Ok, you sold me on the M120's.

So, you would recommend mounting 1" from the chine to fit exactly over
the outer step? Would this be in the instructions for this type of hull?

- thanks Nick

-----Original Message-----

Nick,

Good questions! I should have been a bit clearer in my response. There
will be a noticeable difference in the 80 and 120, with the 120s giving
much better result at lower speeds. Since the M120 (and 80) have drop
fins on the sides of the Tabs you can indeed mount them closer to the
chine since they won't through spray out as much as a "flat" Tab.

Either Trim Tabs will work well on your SeaCraft, but if she were mine I
would mount the M120s.

Let me know what you think.

Tom

-----Original Message-----

Hi Tom,

My concern is if there is a significant difference on this type of hull
with the bigger M120's since the M80's fit nicely in the outer step.

The outer step measures 11", if you install 3" from chine, it leaves you
with 8" span, perfect for the M80's.

If i go with the M120's(10" span), does the extra 2" span that overhangs
on the second step on this type of hull really do anything? I am
assuming you need to still maintain the 3" from chine and not move them
to 1" from the chine to have them fit in the outer step?

I am sure the extra 2" chord on the M120's would provide more lift.
Would it really be noticeable? I guess i am trying to stay closer to the
standard tab 9" chord looks .... 12" seems big ....

Nick

-----Original Message-----

Nick,

Thanks for your e-mail. You are correct, due to the hull shape the 18 x
9 is not the best choice. I have to agree with most of the posters at
the forum, and I would go with the M120s. By the way the M120s have the
shorter actuator as standard so they will likely leave room for a
bracket.

Let me know what you think.

Tom

Tom McGow
Director of Client Services
Bennett Marine