Variable (Controllable) Pitch Propellers

[fishwife]

Hi all

I'm at the very beginning in researching the possibilities of installing a controllable pitch propeller on a largish (62ft) long range adventure type motor yacht. The first thing I'm sure of is that I have no intentions of replacing the entire drive chain. That being so, does anyone know of a prop that can be hung on a conventional shaft that is either self adjusting or can be adjusted from the bridge. I'm looking primarily, to increase range at a given speed, say around 8 knots, though cost is a limiting factor to some extent. The cost may be off set by fuel economy but at this stage I don't know enough to be able to even speculate. I'm reading everything I can get my hands on, both on and off the net, but this is a large reservoir of hands on knowledge and I'd appreciate your input. Thanks in advance.

Paige

[Mule]

Paige;

Look up and research Hundstead. Alos this is an excellent source, BTW with this site go to the home page for all kinds of marine knowledge, a regular google of marine information

Controllable Pitch Propellers. CPP CHOICES

[Talbot]

If you want to manually control, then you will require some form of new shaft and control system - because with a true variable control, there is no forward and reverse through gears, merely a shift in pitch on the propellor.

That would be VERY EXPENSIVE

Autoprop provide a degree of variable pitch which may be what you are after, but I dont know if they make them large enough for your application.

[Chief Engineer]

I am familiar with Hundestadt(sp) Propellers.

You will need a new shaft.

You will also need to install Exhaust Gas Temperature Senders to tell you just how hard the engine is working.

Anyhow...8 knots is 8 knots

They are great units...Europeans have been using them for years in the fishing industry...you can get manual or electric models

[fishwife]

Thank you for the replies. I was aware of the Scandinavian solutions but I guess I was looking for something that just doesn't exist. I'm going to research the cost/benefit aspects of a new gearbox, shaft and prop, i.e. does fuel cost saving and increased range offset over say 5 years running around 1250 hours a year.
(I realised about 30 minutes after posting that the 8 knots figure was an red herring and woolly thinking on my behalf, sorry Chief)

[roblanford]

I have a brand new Hundested electrically operated controllable pitch prop system, a new ZF trans, and a rebuilt 5lw Gardner engine that I was going to put in a 64,000 lb sailboat. The boat is gone. The driveline is available partially or complete.

[roblanford]

Oh yeah, the reason you want a trans is that you can feather the blades of the prop (inline with the length of the boat) and use the forward and reverse gears to spin the boat in its own length either way negating the need for a bow thruster.