What Bow Thuster should I get

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I'm thinking for my 1982 MT DC single 120 hp that I want to install a Lewmar 92lb thrust 12 volt and power it from the Lewmar windlass cables all ready up there in the bow. Will have a fixed control at salon steering station and a remote for the Flybridge station, The rudder from PO s has been extended 3 inches on aft edge and I want to add a 1inch X 4 inch long fishtail on each side of rudder end aft with type 316 ss angles and a level 316 ss 3/8 thick X 6 inch wide plate welded top and bottom to the rudder. I realize that the plates need precise alignment. Comments please.
 
Our Sidepower stern thruster sheared a key where the main bevel gear is attached to the shaft that goes thru the transom to the elec. motor. The boat had to be removed from the water and the thruster gearbox completely disassembled to fix it. There was too much torque for the size of the key, and machining a bigger keyway was not an option. I consider this to be a design flaw. Either the shaft should be bigger, or there should be a spline.

Except for that, our Sidepower bow and stern thrusters have worked well. They are each powered by 2 8D AGM deep cycle batteries in series for 24V. (The rest of the boat is 12V) They are charged by a dedicated 24V charger, so the batteries get charged only when we are on shore power, or when the generator is running. We often use both thrusters at the same time, in the same direction to slide sideways, or in opposite directions to spin on the spot. We have never run out of battery power.

Although I have no experience with hydraulic thrusters, I often wonder how well they work, since the engine is always idling when the thrusters are needed. I once toured a boat where the thruster hydraulic pump was attached to the generator. This solved the low idle RPM problem, but the generator had to be running to use the thrusters.

Our previous boat (a 36ft trawler) had a 12V bow thruster run off the house batteries. That arrangement worked well too.
 
+1 on a sidepower 24v system, that’s what my stern Thruster is and I love it! I’ve run it for minutes at a time with no issues. I think the wire run size and length is important. It has a totally separate charging system and battery bank.
On using the same pump I know very little about hydraulics but I have separate pumps for my bow Thruster and stabilizers, they are very different sized and the bow Thruster is on an electronic clutch, you can really feel it when it is on, I’d not want that running all the time....
 

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