would i benefit from trim tabs?

[d_tuck]

I have a 21.5' 1996 stingray 658zp with 5.7 magnum mpi + engine and bravo 3 drive turning 28p prop. it currently runs high 60s gps I was told I could gain a few mph and stability with some decant tabs I was wondering if there is any truth to this?. I was also wondering if I could stay on plane at a lower speed? currently I have to be going at least 25 to keep the nose down.

 

[Scott Danforth]

yes, tabs in conjunction with trim is a benefit

 

[garbageguy]

I don't know about increasing speed, maybe - but trim tabs offer more control of a boat on plane

 

[JASinIL2006]

I agree... tabs can help with your stability and getting up on plane, but I would not expect to see any speed increase. Given what you have described, something like SmartTabs would probably do the trick.

 

[tpenfield]

Trim tabs perhaps for lower speed. What RPM are you turning at WOT? . . . and a 21' Stingray going high 60's is a real chine walker.

 

[alldodge]

Got plenty of opinions and of different thoughts, and all are good, and maybe not so good

I see anything in the water will create drag, now if that increased drag will benefit in additional speed, I'm not so sure. Do believe it will help with stability because you can keep the chine walking a bit reduced.

A 21 footer doing in excess of 60 mph + mph is good figurin you weight 3600 and have 300hp. My 23 foot also does just reach 60 mph at WOT and weights 4200 lbs with 300hp 454 carb.

was also wondering if I could stay on plane at a lower speed?

Yes, this will happen but also remember that it may also take more gas due to increased drag of the tabs. If you want the best efficient place for your boat to ride, is find the place where the boat runs easy on plane. More then this increases gas used, and as it starts to go back down into the water it also starts using more gas. Get it to this optimum point and use tabs just enough to keep it level and this is your best ride point.

 

[d_tuck]

Wot 5k - 5100 ive thought about having the props pitched up a degree or 2. It gets on plane very well as is im just afraid of pitching too far and ss bravo 3 props are pretty pricey. Ive read the bravo 3 is only good for about 70mph but you can change the lower with proper ratio to bravo 1 and go faster that way but im afraid id lose alot of lift and wouldnt have enough power to do much better. I do like the throttle response of the b3

 

[alldodge]

The old comment of a B3 only good to 70 is not for real. Some folks are doing well above that without issue, its all in setup

The B1 will reduce hole shot but takes less HP to rotate the single prop over the 2 props. Same thing goes with a 4 or 5 blade prop to a 3 blade. The more blades the more power it takes to rotate them.

I'm running a 3 blade 21 and your boat is light so with the MPI you should do fine with a B1. The B3 allows less slippage and therefore more efficiency. If I had a B3 on the Rinker I wouldn't change to a B1.

You can find many prop sets on ebay and craigslist for a lot less, think I have 5 sets now :facepalm:

 

[d_tuck]

Haha 5!? Dont happen to have a 29 or 30 laying around do you

 

[Chris1956]

I doubt trim tabs will do anything to increase top speed. They should let you plane at a lower speed, and help you get on plane, when in the down position.

I would recommend power adjustable tabs. The spring loaded ones (smart tabs) will always drag, and will rob some top speed.

Make sure when you install the power tabs, they can be retracted above flush with the hull. Then they will not drag, but can be lowered to help chine walk and other stability issues.

 

[JASinIL2006]

I would recommend power adjustable tabs. The spring loaded ones (smart tabs) will always drag, and will rob some top speed.

This may be true, but the loss is really pretty minimal. I think I lost maybe 1-2 mph (GPS measured) at WOT after I installed my SmartTabs.

 

[high&dry]

Almost all boats will benefit from real, working, helm controllable tabs of proper size.

 

[ezmac]

Have a 17ft center console century. Had a problem with porpoising. Since I am not able to shift weight forward I mounted smart tabs. Porpoising stopped, planes easier and stays on plane longer but cost a couple of mph. Boat weighs 3000 lbs with a guest and myself, gas, gear and 90hp 2 stroke yamaha. Top speed was around 30, now is around 28 29. Fast enough for me.