I'm wondering if the Pearson will back down to port or maybe just straight back with a right handed prop installed.
My Velvet Drive transmission is symmetrical, so I have that option.
Pete
Pete: Now that is an interesting question.... I don't know much about Nautical design, but I do know a bit about airplanes.
When you design and airplane with a propellor on the nose, under power, the nose will try and turn left. To counteract this, designers either adjust the alignment of the engine mount or add a little angle to the vertical tail so you don't have to keep your foot on the right rudder pedal all day. Because it varies with power and airspeed, it can only be right at one speed and power setting, usually in cruise.
I suspect that Bill Shaw, being the smart guy he was, probably did something similar on the Pearson 365 by making the prop drive shaft come out the starboard side of the hull slightly. The effect of the rotating slipstream would ideally be canceled out by the offset in thrust. If he hadn't, you would not have the rudder centered when under power. That means that if you were to reverse the direction of rotation, the shaft should then come out the same distance over on the port side instead of the starboard side. That change would be a pain in the donkey.
That would leave you with the prop being on the "wrong" side of the boat, requiring you to hold some rudder which would slow you down going forward, unless you are already at your theoretical hull speed, which would mean it would just cost you more fuel to go the same speed.
With respect to backing up, my guess is that the direction of the rotating slipstream would be reversed, the the offset would be on the same side, so it might back up a bit closer to straight because the two effects would be closer to canceling each other out, but it would cost you going forward, but I could have it a backed up :D
I have a 367 with RH, 2-blade, fixed prop. Prop shaft comes out at angle to starboard. The stern walks to port in reverse. It's a pain until you get used to it.
Sounds like prop walk is the dominant force in backing down. LH prop walks to starboard, RH prop walks to port regardless of the few degrees of shaft offset to starboard. Shaw designed that in simply so the shaft could clear the rudder skeg. I'm curious to know what engine and gearbox do you have that allows you to run a RH prop?
Thanks for the feedback. Pete
Hi Pete,
Engine is Universal 5444, Hurth ZF15 transmission, Walter RV-26. Not sure what the reduction is, probably 2:1, that's pretty common.
Don't know much about these except that's what I found on the tags of the devices.
I also concur that the offset shaft is for ease of removal, rather than to mitigate prop walk. It seems like everyone around here, RH, LH, 365, 367 has strong prop walk. Even the 424's have prop walk as bad as ours. I had a Catalina 30 many years ago and don't recall this strong of a prop walk. Same for the various boats I've used and crewed on over the years. Not sure why it's so bad on these boats, but it does come in handy sometimes. Kinda like the crappy access to the engine: you learn to live with it.
The boat's an '82 367.
I have a RH 12-pitch 17 I think......boat just does not run the way I expect...but could be my paragon slipping. I am going to replace my paragon with a Hurth...does anyone know which Hurth I should use and what ratio.....1 to 1? Any ideas of other solutions?
I have the W 40 4-108 that sounds strong and revs to 3600.
I believe the Borg Warner 71c 1to1 is the right one for the westerbeke w40