Trim tab pump motor - Retro fit?

[elv_1986]

Hi,
I have a pair of Bennett trim tabs hanging on the back of my 28ft motor cruiser, with no internals at all. Just tabs & hydraulic cylinders.

I have been looking at the price of pumps & motors, and they seem to be ludicrously expensive! It got me thinking its only a hydraulic pump?

Has anyone had any experience with retro fitting a hydraulic pump & motor off something else, like a power steering system or similar?

Thanks,
Louis

 

[Bondo]

Hi,
I have a pair of Bennett trim tabs hanging on the back of my 28ft motor cruiser, with no internals at all. Just tabs & hydraulic cylinders.

I have been looking at the price of pumps & motors, and they seem to be ludicrously expensive! It got me thinking its only a hydraulic pump?

Has anyone had any experience with retro fitting a hydraulic pump & motor off something else, like a power steering system or similar?

Thanks,
Louis

Ayuh,.... Nothin' could be further from the Truth,.... The amount of engineerin' in that tiny plastic box is Amazin',....

Not only is it a pump, it's the Valvin' involved,...

'n a power steerin' pump Pressures, would Shatter the rams, 1st time out,...

 

[Tabman]

The biggest issue will be the fact that Bennett hydraulic power units used for the Trim Tabs are single acting, and most other pumps are dual acting so they will not work.

We like to support our dealers, and buying a new unit will get you a five year warranty. But have you tried looking at E-bay for a used unit?

 

[smokeonthewater]

It could definitely be done from the power steering pump BUT it would cost WAY more than buying the bennett unit..

First you would need to limit pressure, then you would need to build the valve body... 4 12v solenoid valves would be needed.... Now there are some issues to work around... the pump will vary in rpm so it will be hard to predict the rate at which the tab will deploy and also since the return fluid won't be controlled by going through a pump, the retract rate will vary greatly with the pressure on the tab (ie boat speed) Also you're gonna need a larger reservoir on the pwr steering pump... also don't forget the switches....

Figure somewhere around $1200 if you have the ability to design and build it yourself...


OR $175ish for a used pump on ebay

 

[Chris1956]

Could you set the angle of the tab where you want it for most uses, and plug the oil ports? Maybe you could get it to act like a smart-tab, except it has an "air spring".

 

[JoLin]

Could you set the angle of the tab where you want it for most uses, and plug the oil ports? Maybe you could get it to act like a smart-tab, except it has an "air spring".

Probably wouldn't help. I use mine as much to control list as I do for help getting/staying on plane. They need to be adjustable to be practical.