Thinking of buying 85ft. Hatt extended MY

[WA2DDL]

Oh, one more thing...regarding the handling. The owner said the turns are a bit quicker than a standard 70 footer and the handling is fine. Now, if that came from a "Sunday afternoon skipper" I might not be inclined to believe it. This guy spends his life on the water (deep sea tug owner/operator) and has experience.

...Yet, lets keep in mind that, experience or not, he is still trying to sell it.

[Freeebird]

How could turns possibly be "quicker" than a standard 70?

[miboatnutz]

I would expect turns to be "slower" for a specific engine speed and a wider turning radius compared to a standard 70 due to the increase in hydrodynamic surface area aft of the rudders.

[Walter P]

Some years ago we took a cruise on a friend's 72' MY. It was originally a 64 MY that had been extended
After a wonderful day on the water down to Biscayne Bay and back to Ft. Lauderdale for dinner, we
were heading up the New River from the ICW. It was probably 10 o'clock in the evening. We came to
a right turn in the river and one of the shift cables came off one of the transmissions (stb side) making
it impossible to put the starboard engine into N or Reverse. With both engines engaged at idle speed,
we were unable to make the turn in the river. In an effort to "soften the blow" for the obvious crash on
the far side we placed the port eng in N and shut down the stb while still in gear. Well we had enough
momentum to crash into a small dock behind one of the very nice houses on the river and wiped out
the dock including knocking down the pilings as well as the small runabout that was tied to it. Steering
alone was not able to keep the boat on course. The investigation by the CG determined that the props
and rudders being in the original place when it was a 64 footer caused the boat to fail to respond
properly to the helm.

Walt

p.s. The only damage to the Hatteras was some scratches on the bow which required some filling
and repainting..... Gotta love Hatteras.

[WA2DDL]

How could turns possibly be "quicker" than a standard 70?

I can't tell you too much more than that, that is what I was told. I don't believe he did anything with the rudder size and I didn't feel it was a correct thing to challenge him at that time.

[WA2DDL]

I would expect turns to be "slower" for a specific engine speed and a wider turning radius compared to a standard 70 due to the increase in hydrodynamic surface area aft of the rudders.

The change in handling characteristics was a direct question that I had put to him and his answer was it was actually quicker than it was before. I'm not well versed in Hydro Dynamics, my strong suit is aerodynamics, and I don't think there's a lot of difference between the two when you get right down to it. As I mentioned in the earlier post and just above this one oh, I don't believe anything was done on the rudder size... Such as an increase of actual surface area. It would be interesting to talk with others who have had a boat that was actually lengthened by 10 to 12 feet and find out what kind of handling characteristics they have now vs. Before. As for me, I am just repeating what I was told. Thanks for posing that question

[WA2DDL]

Some years ago we took a cruise on a friend's 72' MY. It was originally a 64 MY that had been extendedAfter a wonderful day on the water down to Biscayne Bay and back to Ft. Lauderdale for dinner, we were heading up the New River from the ICW. It was probably 10 o'clock in the evening. We came toa right turn in the river and one of the shift cables came off one of the transmissions (stb side) makingit impossible to put the starboard engine into N or Reverse. With both engines engaged at idle speed,we were unable to make the turn in the river. In an effort to "soften the blow" for the obvious crash onthe far side we placed the port eng in N and shut down the stb while still in gear. Well we had enoughmomentum to crash into a small dock behind one of the very nice houses on the river and wiped out the dock including knocking down the pilings as well as the small runabout that was tied to it. Steeringalone was not able to keep the boat on course. The investigation by the CG determined that the props and rudders being in the original place when it was a 64 footer caused the boat to fail to respond properly to the helm.Waltp.s. The only damage to the Hatteras was some scratches on the bow which required some fillingand repainting..... Gotta love Hatteras.

Walt that is a very interesting story. I would think that there would be more of an effort to try to turn the boat port or starboard with it lengthened. Just thinking off hand, I would say that the Turning arm has been shortened because the center of gravity has now been pushed aft on the boat slightly with the introduction of the lengthened Hull. Because the arm has not lengthened, rather shortened, the moment necessary to turn the boat, that force that is applied on the Rudders, would need to be more. Meaning more steering input or larger Rudder surface to compensate. Now add that there is additional 10 feet on the back which is moving against the water as well and I would think it might be slower on the response when you try to turn. However, I was told it was quicker, plain and simple. Now, as for the situation that you went through, I think that's extremely interesting because I have been told by a Hatteras owner that you cannot steer the boat successfully on a single engine. I thought that sounded a bit crazy, and maybe some of you Hatteras owners could reply on that as well. Don't mean to start an argument, just wondering about that. And last thing Walt, I was told that when you have a boat of this size in class, much like the one you were just talkin about, anything you touch with it will break! Usually the boat comes out the winner, as you just described. That was really a great story and I'm glad no one got hurt.

[Cricket]

Not sure a stretched boat with an engine out trying to make a turn where there probably wasn't enough room to complete is very relative evidence.
What I do know is we installed larger rudders on our boat and it made a ton of difference compared to the originals, especially in a following sea and also with an engine out.
Power steering is also a game changer compared to non power assisted hydraulic steering.

[Avenger]

Just speculating, but I would think the "tank turn" where you put one engine in forward and one in reverse would be better since the props are closer to the center of gravity. But the underway steering would be worse for the reasons mentioned above.

Maybe it's the two different turns that these boats can do that's causing confusion. Maybe?

[Walter P]

Cricket, I'm glad to hear from you that the larger rudders made a big difference, especially in a following
sea. I was going to install larger rudders on my last Hatteras ('82, 48MY) but I was afraid that since it
already took a lot of effort to steer, the larger rudders would make it that much harder. Power steering
was probably what I should have done. Avenger, the "tank turn" is what we were attempting to do
when the control cable let loose. It always worked very well. As far as handling with only one engine,
well I definitely agree with you. On a regular relatively straight run, one engine steering is fine, but
trying to handle the boat in close quarters was a chore. It sounds like we are building a good case for a
bow thruster.

Walt