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Turn knobs instead of switches for trim and tabs?

Old 10-30-2008, 01:47 PM
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Default Turn knobs instead of switches for trim and tabs?

My boat is very sensitive to weight/wind and balance. When I go to adjust a tab or the trim I always over compensate because there is little control over power to the pumps. Could a knob be used to adjust the amount of power to pumps? Do the joystick type controls do what I am asking or do they operate like the switchs?

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Old 10-30-2008, 09:42 PM
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You might want to try the older style pumps which have the same motor but have a metal resevoir rather than the plastic tank. The mercruiser style pumps tend to "over-run" a little even after you let off the switch. I noticed it mostly when I switched from the old to the new style on my Allison. Made a difference.
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Old 10-30-2008, 10:05 PM
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The wire that goes into the switch is for a relay at the pump. If you change the voltage going to the switches the only thing you will do is burn out your relays faster. You would have to lower the power at the pump but that also would probably lower the life span of the pump. As ziemer said you may want to try a different pump.
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Old 10-30-2008, 10:37 PM
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it could be done, not with stock parts, might be able to do it with a servo operated flow valve, but it could get complicated in a hurry....
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Old 10-30-2008, 10:42 PM
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How about a thicker oil? Then the pump will run a bit slower; tab will move a bit slower, and you will be able to fine tune a bit better.
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Old 10-31-2008, 12:08 AM
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My tabs do the same thing it drives me crazy. one always stays moving slightly longer than the other after I let go of the button so they are never the same.
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Old 10-31-2008, 02:55 AM
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I believe everyone that fine tunes their ride via trim and tab has experienced this same issue. When is the boating industry going to produce controls that are 100% precise? Does anyone build quality? After all, the average new boat price is far greater than the average automobile price, yet we have sub par to average quality controls to choose from. Why haven't automobile or aircraft quality controls made their way into the boating sector?
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Old 10-31-2008, 08:18 AM
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How about something that does your tab adjustment off of your indicators? You can have a couple of 10 position knobs with some hefty detents. You're running at 3 and want 5? 2 clicks clockwise. It wouldn't matter if 1 pump was faster than the other, as the indicator would know when it hit the position, and stop the pump. If it had a little overrun on 1 tab, the indicator would know it, and move it back a hair till it's perfect. You can leave the rockers for fine tuning (5 1/2 position). You could also do it all manually with the rockers if you wanted with an override button of some sort.

This could all be done electrically (not by me ) . You'd just have to ensure your indicators were adjusted properly.
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Old 10-31-2008, 09:48 AM
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Nothing like a nice electronic feedback system to raise costs while drastically complicating what is an extremely simple system.

I think thicker oil may be a better idea!
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Old 10-31-2008, 10:07 AM
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Maybe smaller valving somewhere in the system. Most of the rams used in boats are built with stock internal hydraulic pieces. Restrict the flow to inflow and outflow of the rams. That would slow down the movement giving greater control. Might make the pumps work harder?
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