:oI am starting to work on a 150 ft vessel with twin inward turning cpp and I am wondering if anybody has experience operating this type of propulsion. I have been unable to find info on how to maneuver with these. Please help ! I have experience with twin fixed pitch and single screw. Oh by the way the v/l also has a bow thruster.
[QUOTE=“trickiepoo;103580”]:oI am starting to work on a 150 ft vessel with twin inward turning cpp and I am wondering if anybody has experience operating this type of propulsion. I have been unable to find info on how to maneuver with these. Please help ! I have experience with twin fixed pitch and single screw. Oh by the way the v/l also has a bow thruster.[/QUOTE]
Should handle pretty much like twin screw fixed pitch vessel when “twin screwing”. When you put an engine astern on either type of vessel, that prop turns inboard with simliar tranverse thrust effect. Difference may be noted in astern power. The stopping effect of an astern bell is usually a lot less with CPP. Also, CPP vsls tend to creep ahead or astern when props are set to neutral pitch (stopped). Good idea to de-clutch as soon as you are in final docking position. Also helps keep mooring lines from getting caught in props.
Really there’s not a more experienced captain to explain how that vessel likes to perform? Hell I’ve asked deckhands sometimes how to best do things on a new boat.
It will pivot like normal, walking might be a little difficult, but even on fixed pitch boats I just pivot my stern and use my bow thruster to walk when I cant get it to walk with out the bow thruster. If I’ve got a split rudder system I will sometimes position each rudder in board to increase my pivot speed when ever that engine is going forward. Some boats like all the rudder you can give them, the one I’m on now prefers about 20 degrees.
There are a lot of subtle differences between fixed and CP when it comes to slow speed maneuvering. One in particular is when on a fixed wheel (twin outboard turning) vessel you can drop the starboard in reverse, leave the port out of gear and your stern will dependably go to port aft. The torsional effect of that one propeller turning starts at the first revolution with nothing to counter it and can be used as a huge advantage. With CPP both wheels are always turning canceling each others side movement so you lose that initial “bump”. If you put your starboard in reverse pitch initially you could slide off to starboard just as well as port. You need the other wheel pitching forward to guarantee the initial port movement. Even then you will want the forward thrust going across the rudder to slide your stern over. Like Jemplayer said, if you have split rudders turn them inboard, find their sweet spot and leave them when maneuvering. The part about both being inboard turning isn’t going to make much of a difference in most cases. At first you’ll feel like you’re slipping and sliding everywhere but you’ll get use to that, then you’ll expect it and after that you’ll depend on it.
I can’t believe someone asked this.I have experience but how do you handle a boat.
Why the heck not? Come on man, he is asking an honest question…why don’t we stop comparing the size of our dicks for a moment and help somebody, is this that big of a deal? Really?
[QUOTE=“Louis;103762”]I can’t believe someone asked this.I have experience but how do you handle a boat.[/QUOTE]
What??? Do you think all “boats” handle the same way, and that discussing ship handling on this forum is out of line?
Another thing that you will notice is that when you walk a boat with CPP you will have to use more power than a fix prop to get the pebble wheel effect.
Pebble wheel effect huh? That must be where your props are walking along a gravel bottom!
Pebble wheel effect huh? That must be where your props are walking along a gravel bottom![/QUOTE]
LOL You know it! Sounds like you have done that before!!
Paddle Wheel not Pebble Wheel!!