Thruster Performance

[Bobby P.]

On my 31 CB, the bow thruster performs pretty well.

The stern thruster, in any wind, is weak.

Has anyone tried any modifications to the sternthruster? I've heard talk about switching out the prop, but no reports.

Thanks,
Bobby

 

[dbsea]

following.

 

[Bruce Moore]

Based on my experience in three Ranger Tugs with thrusters (R-25, R-29, R-31) I learned to rely more on kicking the stern with brief pulses against a hard over rudder. The bow thruster is more effective because there is much less hull resistance and much less weight to move. The stern is full beam and houses the engine, etc.

Once I built up the motor memory I rarely used the stern thruster unless there was no wind or current, or if I wanted to move the stern in the direction of those forces. Learning to manage the stern by feathering a 200-300 HP engine will serve you well in close quarters, especially in combination with the bow thruster. One exercise which helped a bunch was learning to pivot the boat 360 degrees without making significant headway - brief feather of prop against hard over rudder followed by a brief feather of prop in reverse, repeat.

Cheers,

Bruce

 

[GaylesFaerie]

...I learned to rely more on kicking the stern with brief pulses against a hard over rudder. The bow thruster is more effective because there is much less hull resistance and much less weight to move. The stern is full beam and houses the engine, etc.

Well explained. Also, on the R27 (R25 as well but not sure about the 29 and 31) the stern thruster is mounted a couple of inches away from the port trim plane and the rudder to starboard, both of which impede the thruster water flow coming out of the thruster tube. Not ideal. Make sure your trim planes are up when docking. The stern thruster does have some effect when no current is present. HTH, Gary

 

[bill46]

Agree with Bruce. Stern thruster is nearly useless, kicking with rudder and short burst of power is much better This was only way with single screw before thrusters. The bow thruster is a wonderful tihing!

 

[aintmissb]

Just to agree with Bruce - with my C28 found it helpful to think of the boat as more or less anchored in the water under the centre of gravity which is likely under the engine i.e. the aft cockpit. Manoeuvres then consist of using the bow thruster to rotate the bow, which it does well, and the main prop to push the big heavy stern around - in the direction of the shaft of course. The stern thruster doesn’t really add to this, but thinking that it does provides an unhelpful distraction! Cheers, Roger, Kingston, ON