According to Bennett if I mount the pump in the forward cabin the reaction time will be slower because of the longer hyd. lines. Makes sense, question is how much slower and is it significant. Anybody done this?
Tab pump location
- Thread starter cdwood
- Start date
Jelly, that sounds like the spot I had in mind. How does that work out when pump needs attention ie; adding fluid or whatever?
reaction time for what?? how fast do you want to change the attitude of the boat anyway?
my 232 had it below the starboard berth against the bulkhead. you can page thru some manuals on the gw site to see where it is located on various models. ron
my 232 had it below the starboard berth against the bulkhead. you can page thru some manuals on the gw site to see where it is located on various models. ron
Ron, exactly what I was thinking.
Being new to the tab thing, does location make that big a difference?
Being new to the tab thing, does location make that big a difference?
I have a 265 ,therefore longer lines, and the location works great. Certainly not a problem being that far from the actuators.
cdwood said:
just in the ability to get at the pump for install and service. when you use tabs, you slowly make adjustments. i'm sure there is a limit as to how far the pump can be from the tabs before it's pressure will dissipate in the lines, but i don't think that is a problem on our boats. ron
My tabs are on the way, Was looking at the same place for mine too, the hyd system is closed and if pressurized and air bled the speed should not be affected. But if air gets in the lines then it would affect the speed as it would have a sponge affect as it bleeds out the air, the more line the more air. So, I am not sure how long it would take the pump to bleed out the air but this design should not have this issue if installed correctly. You may have to run the tabs up and down more than 3 times on the initial install to get all the air out.
My buddy has a 26ft cc and his pump is way up under the seat in front of the console and his work perfectly. Plus he said his lines have 3ft difference as well. He has had them for 5 yrs and has never touched it.
My buddy has a 26ft cc and his pump is way up under the seat in front of the console and his work perfectly. Plus he said his lines have 3ft difference as well. He has had them for 5 yrs and has never touched it.
This is where it was on my 265 and no problem getting to it and it was out of site and out of the way. Never had a problem with trim tabs and they worked very well and fast. I think on most GW WA boats you will be able to put it in that same place.cdwood said:
I am surprised that Bennet would say that having the pump farther away would change the reaction time of the tabs in any way. Why would they even say that?
A proper hydraulic system with no air is going to react immediately regardless of length. Hydraulic fluid is a non compressed medium that simply transfers the pump force to the area that can expand and contract.
And just to confirm this.... Pretty much all Grady's have hydraulic steering- the pump for the steering is at the helm, routes down the starboard side, makes its way through the transom, then connects to the cylinder attached to the engine(s). Properly bled, any input at the helm provides instantaneous reaction at the engine.
A proper hydraulic system with no air is going to react immediately regardless of length. Hydraulic fluid is a non compressed medium that simply transfers the pump force to the area that can expand and contract.
And just to confirm this.... Pretty much all Grady's have hydraulic steering- the pump for the steering is at the helm, routes down the starboard side, makes its way through the transom, then connects to the cylinder attached to the engine(s). Properly bled, any input at the helm provides instantaneous reaction at the engine.
Chris,
Thank you for your email.
Regarding the Hydraulic Power Unit mounting location on your Grady White, it would be optimal for the pump to be mounted as close to the actuators as possible. When tubing runs are increased, you will notice a lag is response time. It is not necessary to keep tubing lines equal in length, however, you will notice a increase in response time with longer tubing runs.
Please let me know If you have any furtherquestions.
Regards,
M.J. Thomas
Account Manager
Bennett Marine, Inc.
550 Jim Moran Blvd.
Deerfield Beach, FL 33442
Service hours: 8:00 am - 5:00 pm Monday - Friday (EST)
Phone: (954) 427-1400
Fax: (954) 480-2897
www.bennetttrimtabs.com
sfc- where'd you go for your tabs?
Thank you for your email.
Regarding the Hydraulic Power Unit mounting location on your Grady White, it would be optimal for the pump to be mounted as close to the actuators as possible. When tubing runs are increased, you will notice a lag is response time. It is not necessary to keep tubing lines equal in length, however, you will notice a increase in response time with longer tubing runs.
Please let me know If you have any furtherquestions.
Regards,
M.J. Thomas
Account Manager
Bennett Marine, Inc.
550 Jim Moran Blvd.
Deerfield Beach, FL 33442
Service hours: 8:00 am - 5:00 pm Monday - Friday (EST)
Phone: (954) 427-1400
Fax: (954) 480-2897
www.bennetttrimtabs.com
sfc- where'd you go for your tabs?
I am interested to understand the rational behind the response. Pascal's law states that "pressure exerted anywhere in a confined liquid is transmitted equally and undiminished in all directions throughout the liquid." The fundamental principle of hydraulics is that the force exerted on one end of a hose will be matched on the other end. The only way to have a pressure loss would be for the hose itself to expand with the exertion of pressure, something hydraulic hoses are designed not to do.
Bennett tabs ship with their own hydraulic line- perhaps these are just not as robust as hydraulic lines for steering and they swell a little bit with the pump pressure, creating more fluid needed to actuate the tabs. ???
Never noticed a lag time on my tabs, and the pump is mounted under the aft birth like most Grady's I am aware of.
Bennett tabs ship with their own hydraulic line- perhaps these are just not as robust as hydraulic lines for steering and they swell a little bit with the pump pressure, creating more fluid needed to actuate the tabs. ???
Never noticed a lag time on my tabs, and the pump is mounted under the aft birth like most Grady's I am aware of.
cdwood said:
I agree with halenalu. Hydraulics are like "fly by wire" . Only side effect on a properly functioning system is extreme cold as the fluid gets thicker it may get slower. length shouldn`t matter, look at backhoes and excavators.
I think the "lag" time would be most noticible when the tabs are fully retracted. There'a no pressure in the system at that time, so the first time you go to use them, the pump has to pressure it up. The longer the lines, the longer the delay. Once they're in use, provided they're not fully retracted again, there shouldn't be any delay.
However... the pump on my Gulfstream was factory mounted under the starboard storage compartment, in the cabin, (like everone is saying). It always seemed to me like there was a slight delay, even if they were already applied. Was it a big deal?... not really.
With that said, I've insatalled Bennitt tabs on atleast a half dozen different brand boats, (20 to 24 footers). On everyone of them I always mounted the pump in the bilge area. So, if it were me, (provided there's room) that's were I would install it. Shorter lines... battery ground is near-by... it's just less work over-all. Try to mount it were it's accessable, (incase you ever have to add fluid), as high as possible and as level as possible.
However... the pump on my Gulfstream was factory mounted under the starboard storage compartment, in the cabin, (like everone is saying). It always seemed to me like there was a slight delay, even if they were already applied. Was it a big deal?... not really.
With that said, I've insatalled Bennitt tabs on atleast a half dozen different brand boats, (20 to 24 footers). On everyone of them I always mounted the pump in the bilge area. So, if it were me, (provided there's room) that's were I would install it. Shorter lines... battery ground is near-by... it's just less work over-all. Try to mount it were it's accessable, (incase you ever have to add fluid), as high as possible and as level as possible.
got em on e-bay. There response to your e-mail is weird, some of our vehicle systems use a similiar setup and they move at the flick of the trigger, and they a a good 15ft in lenth, have been working with hyd in the mil for years and have never heard of lag in lenth of lines. Even ones as simple as this. I am curious, will have to test this when I get then to see. set up one with a long tube and one with a short tube and see if they move different speeds. Maybe a difference of fraction of a second. Fun stuff.
Gee guys...mount it on the inside transom under the storage bin next to the battery and use matching 3' lines. Easy to service, install, and see if it is topped up with fluid. Mine is on the port side.
I haven't touched mine in 3 years. They are the 12" tabs, more than enough for the boat.
I haven't touched mine in 3 years. They are the 12" tabs, more than enough for the boat.
CJ, New motors already got the scuppers lower than I want them, so the pump will be going in the forward cabin location.
3' lines on an 8' transom, how do you make that work?
Also, with a new transon in place not looking to put any more holes in it than is absolutely neccesary.
3' lines on an 8' transom, how do you make that work?
Also, with a new transon in place not looking to put any more holes in it than is absolutely neccesary.
cdwood said:
Are you kidding? The pump can't weigh more than 3-4 lbs. And you're afraid of holes for the mounting screws for the pump? On the inside?
You have to drill holes for the lines and to mount the tabs and actuators regardless of where you mount the pump. And that's all on the OUTSIDE of the transom.
The pump mounts between the two tabs, on the inside of the transom, 3' line will reach easily. Okay, use 4! A helluva lot easier that running them all the way thru the boat.
It makes no difference to me, for your boat, but at least come up with a valid reason. :wink: