52' COCKPIT MY 1997 - SPEED & PRM

[Raymond]

Hello to everyone! Great forum.
I'm now in the process of acquiring my third Hatteras. This time I will go with the 52’ Cockpit MY 96 – 97.(HATES)
Last week I went to see and inspect a vessel w/ an engine surveyor to inspect the engines. (8V92TA). He said that for the reported 1100 hr., the engines look inside very good. He said that if no hr/meter were on board he would think the engines would be “ a couple hundred hours”. Very, very little white smoke at cold start, for about 30 sec. only. The hull bottom was optimally clean.
It has a pair of DD511 Twin Disk (3.92:1) and a pair of 38” X 72” Pitch Propellers.
At sea trial, no smoke at all was observed, and relative calm sea.
Only 2150 and 2175 RPM were obtained @ 25 mph SPG GPS. (empty tanks)
As I understand, this vessel should be @ 2350 RPM, and about the same top speed.
I do not have the factory specs in terms of speed, propellers and top RPM’s for this boat and I’m currently wondering if it is a over-propell situation as the engine surveyor thinks , or actually a “dying” engines.
Engine Coolant Temperature reach 190 at helm, 175 mechanical at water jacket, measured with a temp gun, and “cero blow-by”.
- What should or was… the factory propeller specs?
- What Max. RPM should I be able to get whit this propellers?
- Is there any way to know for sure that it is an over propeller case or lacking power engine?
- How the performance of this vessel compare whit the reported numbers on the BOATING Magazine Aug. 1990. ?(See the doc. In the reports section.)
I really liked that boat, but the RPM,s not getting where they should be, make my nervous.

Any comment at all on the subject will be appreciated.

Thanks’ Raymond

[Freebird]

[QUOTE=Raymond]
It has a pair of DD511 Twin Disk (3.92:1) and a pair of 38” X 72” Pitch Propellers.

Damn bubba, I ain't know rockit scientist or nuthin', but the props on my helicopter ain't even pitched that high! I'd say those engines are dyin' for sure tryin' to pull 72 inches of pitch. As best I can figure, if you're pullin' these puppies at over 2,100rpm, you outta be cruisin' at about 90mph based on the new math. "You ain't from around here are ya?"(just kiddin') All kiddin' aside, check with Detroit to get WOT rpm (would have thought your surveyor would have known this). You can also call Hatteras directly with your hull number, and they will be able to tell you which props originally came with the boat. They will also probably be able to help you with performance numbers on the boat with that engine package. All things considered, I would have to think you are over-propped. Not 72 inches worth, but over-propped. Good luck on yore deep pocket purchase. Happy Hattin'.

[SKYCHENEY]

I think those had 5-blade Veems on them. I have seem one of them so I can't be sure. Call Hatteras with the hull # and they will give you all of the info you need.

[Raymond]

Hello!
I communicate myself with Hatteras. It turn out that that the boat left the factory with propeller even larger, (38” X 76” Pitch)… They said that it was designed that way because the 3.92 reduction ratio. It got 28.8 mph @ 2360 RPM at the factory sea trial, with full tanks.
This vessel got a pair of stabilizer add on, after market, and the reduction in pitch may have been to compensate for the extra drag. Because the engine seems to be in good condition, Hatteras recommend an exhaust temperature reading double check to verify fuel restrictions problems.
I’m going to pay for a full tune-up and recheck of the engines, and will let you know all.
Any, comments appreciated! Raymond