Twin screw handling question?

Props and Rotation Do Not Matter

I have yet to meet a seagoing lady that does not move her ass starboard when you ring up an aft bell on the port shaft. Same goes for forward on starboard, shes moving to starboard abaft the beam and to port forward of it.

Opposing thrusts on each shaft will increase the lateral movement that can be additionally increased or decreased through rudder angle adjustment. Efficiency in this maneuver is exacerbated with inboard turning wheels.

A flatter bottom will allow the bow to be more compliant in the walking maneuver whereas a deeper keel necessitates the use of a bow thruster to to maintain the ship perfectly parallel to the quay as she walks towards or away from her berth.

I have seen it no other way in 40 years at sea......

That's just my opinion.....I could be wrong ;-)

This is what we are all saying. Do you know if it is the same regardless of the props rotation..?

As I said above, the inboard turning props are not as efficient in the lateral "kick". The outboard rotation provides the addition of wheel effect in the direction you are twisting. That is when the rudder angle can assist in additional lateral movement as well.

Thanks, I couldn´t follow the wording exactly. May I add that on sterndrives with 2 x Duoprop, (probably same with Bravo 3), which means 4 counterrotating props, you get a sidewalk by steering the drives to the side you want and give reverse on that side and forward on the outer. (I hope I said it right, I always do it without thinking.. )

With the outboards you enjoy the advantage of being able to actually steer the thrust (propellers) providing additional lateral control just as you do with jet drives and azimuth drives.

Further to a comment above, you can play more with the wheel effect of CPPs while using negligible thrust.

I was talking about traditionally handled drives, not the new where they rotate individually (just like jets or pods).

Inboard spinning propellors don't have nearly as much effect on twisting the boat or walking it sideways as outboard turning props, you generally have to give them throttle to get them to react similarly, but that is also how they are more efficient when running as the propellor thrust is sent out in a more narrow area.

Just to add a bit of thought..... the downward angle of the shaft changes the pitch of the prop at the 3 o'clock and 9 o'clock positions. Therefore looking from behind a twin propped boat with counter rotating outward turning shafts/props, (port turning counter clockwise and starboard turning clockwise), the outboard arcs of each prop have the greatest prop angle and therefore most thrust. That is to say, 9 o'clock on the port prop and 3 o'clock on the starboard prop have the most angle and thrust. Therefore from a leverage perspective gives the most responsive handling. Also the most action when the rudder interacts with the most powerful segment of the prop wash.
ie, underway forward, turn the wheel over to starboard, the starboard rudder gets slightly more pressure as it intersects the 3 o'clock wash from the starboard prop than the port rudder gets from the weaker wash from the reduced pitch from the 3'oclock position on the port prop.

Anybody with experience on the early 80's 56 Hatteras know if they can be walked sideways (no thrusters)?

Thanks guys. That's what I thought since she does have a keel. Pascale, DK about pivoting 74,000 lbs off a piling. You're a better man than I. Hopefully I won't have to do that too often.

Fortunately I'm an old fashioned guy. Done it many time with single screw and steel and aluminum hulls. Fiberglass Careful does it.

I have owned and operated one for 5 1/2 years. Put about 10,000 miles on it, take it out all the time. The short answer is yes. It does have a fairly deep keel. I have a thruster but I forget to use it half the time. Turn the wheel away from the dock and use the shifters.