TRIM TABS

[Guest]

I have a 22' Mako centre console with twin 90hp outboards on brackets and a am considering installing trim tabs.

Anyone had any experience with trim tabs and any tips re the installation that may not be found in the instructions (I do read them)

 

[Guest]

Re: TRIM TABS - dont do it

I have a slightly smaller centre console with outboard and find the hydraulic outboard trim gives easily a big enough range of trim angles, so tabs would be superfluous. In fact it is a "purer" solution to trim the engine thrust direction using the engine trim; tabs are just the next best thing when you cannot adjust the thrust angle, ie on a shaft drive boat. But the deployment of tabs will add drag whereas changing the engine trim will not.

Tabs will increase your planing area but I expect that's insignificant on a boat the size of yours?

 

[Guest]

Re: TRIM TABS - dont do it - BUT ......

My challange is that with 5 adults, a full tank 60 gallons and with the engines nearly trimmed all-in the angle of the hull feels like I am driving-up-hill. If I trim all-in the revs drop by 10% or more with the accompanying loss of speed.

I was trusting/hoping that the tabs by increasing the planing area may "lift" the stern and thereby "flatten out" the running angle for a better running trim and reduce the height of water I am pushing.

I was looking at 12" x 9" (yes the are USA sourced)

Any further input appreciated

Thanks

 

[Guest]

Re: TRIM TABS - dont do it - BUT ......

Not quite the same thing but some years ago, I had a Fairline Mirage with twin 125hp engines on outdrives. The boat with any kind of load would struggle to get "over the hump" which was between 12 - 14 knots. I fitted Elltrim electric tabs which were excellent and pretty well trouble free. They were also easy to fit with the only thru transom holes being well above the waterline. Elltrim help with tab size selection also.

The net result was that the hump speed came down to about 10-11 knots, hence no trouble getting on the plane. They also added 1 knt to my overall top speed (up from 22 to 23 knts. so drag may have existed but getting the hull to a better running angle was more important.

The dinette in said boat was to port and if the crew chose to sit below at the dinette it was east also to adjust the trim to bring the boat back level.

Nick

 

[Guest]

have you tried.....

Doel-fins on the outboards? - these bolt onto the cavitation plate and are suppoed to help planing etc.

I don't have personal experience of these but know of a couple of boat owners who have fitted them with some success.

 

[Guest]

Re: TRIM TABS - do do it then

Hmmmm...see your point. What I meant was, dont use tabs to do what your engine trim can do. But if your engine trim cannot do it I agree with you and others, use tabs. No other choice really, apart from redistributing weight but I guess you've already tried that (60gals fuel = 500lbs weight, any chance to move that forward? On mine I have a custom tank under the centre console instead of using stern fuel tanks). Good luck

 

[Guest]

Re: have you tried.....

Tabs are fab, so are doelfins, In fitted a doelfin on my 16ft 6in sports/ski boat with 90hp outboard. It would fly on the fin with little or no hull in the water, with much better out of hole response. With a 21ft 6in boat with 275hp duoprop, the Tabs helped in efficient use of props, setting the leg in neutral position and using the tabs to hold the boat in in rough conditions i.e. force 7 SE North Sea Amble to Whitby. I would thoroughly recommend fitting tabs for your situation they will make a significant improvement to getting over the hump. As for drag when you are fully on the plane the tabs can be fully up and producing no drag. Go for at least 1 size bigger than recommended size. In this case bigger is better.

 

[Guest]

Re: I will try the tabs . . .

I have Doel-fins on the outboards already. The Mako does currently run a little too much up hill, so I am really trying to fine tune the ride.

PS I am a great fan of Doel-fins. They increased my top and crusing speed and the speed for getting on the plane dramatically. Fuel consumption dropped as I was able to cruise at lower revs. This however was with a 75hp Yamaha on a 23'0" centreconsole pirogue (6'0"beam).

I will try the trim tabs after all it is only money and another hole or two in my boat.

Will keep you informed.

Thanks all.

 

[Guest]

Re: I will try the tabs . . .

I have Doel-fins on the outboards already. The Mako does currently run a little too much up hill, so I am really trying to fine tune the ride.

PS I am a great fan of Doel-fins. They increased my top and crusing speed and the speed for getting on the plane dramatically. Fuel consumption dropped as I was able to cruise at lower revs. This however was with a 75hp Yamaha on a 23'0" centreconsole pirogue (6'0"beam).

I will try the trim tabs after all it is only money and another hole or two in my boat.

Will keep you informed.

Thanks all.