How big are you trim tabs vs. size of your boat?

[MiddlepointBight]

Curious what size of tabs people are using. Bought a boat last summer that came with what seem like very large tabs. It's a 21' Hourston cuddy with and original pod. 2003 HPDI 175hp Yamaha 2 stroke on her.

Tabs are ~9 x 24" (Bennett hydraulic) - some photos below. The effect of subtle trim adjustments really swing the boat around.

Thanks for the thoughts.
MPB

 

[spring time]

I got a 18 ft trophy and mine are 9 x18 I got the biggest that would fit

 

[Sr SQ]

9x24 on my Searay 24 and they are very effective, so on your 21 they may be a bit touchy.

 

[ericl]

I was told by an expert boat fitter that trim tabs increase your hull planing surface & that bigger is better.

 

[MiddlepointBight]

I was told by an expert boat fitter that trim tabs increase your hull planing surface & that bigger is better.

I get the planing surface and effects, but to me, the more surface area gliding through the water (i.e. larger tabs) the more friction and thus slower the hull speed (?)

 

[Rain City]

I get the planing surface and effects, but to me, the more surface area gliding through the water (i.e. larger tabs) the more friction and thus slower the hull speed (?)

Unless the tabs are pushing more of your hull up out of the water. In my pig if I go no tabs she bogs down a bit as the butt end drops. The flatter she sits the more efficiently she seems to run. This wasn't the case on my old boat.

 

[easydoesit]

20 foot Grady, 200 HP main. No tabs, no problem.

 

[Brando]

20 foot Grady, 200 HP main. No tabs, no problem.

You may not have a problem but tabs are one of the best additions I have ever done on my boat. Night and day difference once you have them you’ll wonder why you waited so long.

 

[baddogg]

Campion 542, 9x12, provides side to side stability

 

[easydoesit]

You may not have a problem but tabs are one of the best additions I have ever done on my boat. Night and day difference once you have them you’ll wonder why you waited so long.

Appreciate the advantages they provide on larger boats or boats with soft chines. Hmmmmm, maybe I should get a bigger boat?

 

[Brando]

Appreciate the advantages they provide on larger boats or boats with soft chines. Hmmmmm, maybe I should get a bigger boat?

My boats smaller than your grady still would never not have the tabs after making the switch.

 

[MiddlepointBight]

Does a pod-mounted outboard change the performance / impact / size requirements of tabs?

Hull is a 21' but LOA including pod is closer to 23.5-24'

Maybe explains why the original owner added 9"x24" tabs.

 

[ReelSlim]

Does a pod-mounted outboard change the performance / impact / size requirements of tabs?

Hull is a 21' but LOA including pod is closer to 23.5-24'

Maybe explains why the original owner added 9"x24"

There is a lot of discussion around podding a boat and the effects both good and bad. Is it a true hull extension style or a stepped pod or even a bracket? I think adding a pod to a boat after the fact needs some serious pondering or the results will be less than what someone might want...IMO My hull is 25' and closer to 28' with the pod. The boat rides well and I never use the tabs other than to level the boat if I have a few people on the other side of the boat. Even so the boat is very quick to respond to any tab I use. I honestly hit the switch as fast as I can otherwise it almost over corrects. They are electric tabs so they probably are faster than my hydraulic ones on my last boat. I'm not sure why yours are so big unless he got a deal on them at some point? lol Mine are much smaller and very responsive so again just because it's podded isn't the reason.

 

[MiddlepointBight]

There is a lot of discussion around podding a boat and the effects both good and bad. Is it a true hull extension style or a stepped pod or even a bracket? I think adding a pod to a boat after the fact needs some serious pondering or the results will be less than what someone might want...IMO My hull is 25' and closer to 28' with the pod. The boat rides well and I never use the tabs other than to level the boat if I have a few people on the other side of the boat. Even so the boat is very quick to respond to any tab I use. I honestly hit the switch as fast as I can otherwise it almost over corrects. They are electric tabs so they probably are faster than my hydraulic ones on my last boat. I'm not sure why yours are so big unless he got a deal on them at some point? lol Mine are much smaller and very responsive so again just because it's podded isn't the reason.

Interesting... copied the pic of pod here for you. It's an original build, and I am pretty sure the trim tabs were installed when the boat was new as well. It's a custom Hourston pod, and there aren't many I've seen like it for a direct comparable.

Never had a chance to run her without tabs, so I have no idea how she'd go without. There is also a Stingray hydrofoil on the outboard (came with it). Does seem like a lot of **** in the water at transom for lift, but having never ran her naked, not sure how essential they are.

The tabs are super touchy though, the overcorrection can be kind of alarming if you either hit it too long and or the wrong tab/way!

 

[mbowers]

I get the planing surface and effects, but to me, the more surface area gliding through the water (i.e. larger tabs) the more friction and thus slower the hull speed (?)

Properly installed tabs do not touch the water at all when fully retracted and on plane so size makes no difference in that position. When the tabs are deployed, the bigger tab will achieve the desired effect with less tab in the water and at a more efficient angle of the tab. Therefore bigger tabs are almost always better.

 

[23Hourston]

Properly installed tabs do not touch the water at all when fully retracted and on plane so size makes no difference in that position. When the tabs are deployed, the bigger tab will achieve the desired effect with less tab in the water and at a more efficient angle of the tab. Therefore bigger tabs are almost always better.

My old 23 Hourston had 30 inch long tabs per side. It originally came with a command bridge.