N. K

FeatherStream A-Hub 3B

Neptunian

“Hi Nick, Initial feedback of FeatherStream fitted to Neptunian 33′ motor sailor.

 “Firstly, very impressed with manufacturing standard, packaging and instructions. I am a retired Marine Artificer and later Marine Engineer, so have some background.”

 “Newly fitted prop on clean hull, calm conditions”

 1 – Harbour trials showed the prop to be less efficient at tickover revs and gave a slower speed ahead, which is what I wanted. 

2 – Speed astern was faster and with less prop walk (because flat blades do not have the problem of reversing the effects of a fixed blade with the aerofoil one side and scoop the other?).

3 – Full speed trials gave lower speed through the water per 100 rpm but achieved hull speed (7.2 kts) at 3000 rpm, just below full throttle, which was not reached before.

4 – Feathering

I had some concerns about my TMP 12000 hydraulic gearbox not allowing the engine to be stopped in gear, thus affecting my ability to ‘back torque’ the shaft to trigger feathering.

Fitted reflective tape and a spotlight onto the shaft and tested disengaging drive (at 200 rpm steps up to full speed) from driving ahead:

At all speeds, the shaft stopped dead immediately, within a few revolutions, and remained completely stationary until drive re-engaged, therefore I conclude shaft back torque is not needed, only water flow ‘reversal’ on the rear bulge of the blade (?)

The improvement in sailing speed is felt, but difficult to quantify and will take longer to assess.

 “Conclusions – Excellent product, well made and presented. Does exactly what is claimed. I am well pleased. The prime reason for purchase was the feathering, which is faultless. No more noisy trundling prop and gearbox/shaft bearing wear whilst sailing.”

Neptunian 33’ motor sailor – 3B FeatherStream