1982 55C High Performance Series

[Sparky1]

The 55C I'm moving is designated as a "High Performance Series" as per the original badging. It has 12V71TI's which apparently had been bumped to 825HP with 140 injectors according to some notes from the PO.

First question, does anybody know what these engines would have been rated at from Hatteras with this High Performance designation?

Second question, according to more notes from the PO, the engines burned 74GPH @ 20 knots, but there was no RPM listed. I'm far from being an expert on such things, but that sounds like an awful lot of fuel for such a relatively low speed. The same notes showed 11GPH at 8 knots.

Third question, why is so hard to find injectors for these things? Sounds like Rodger has tracked down four, but that's only going to fix the port. Chances are we'll need more for the starboard as well. The engines have supposed been set up for 650HP with the present injectors, but it would seem there is some question about that also.

Factor in two sets of props with totally different specs, and we've got a lot of variables here. The props that are installed now are 30x28 three blades. They had been 30x29 but were recently re-worked. We have onboard the previous 4 blade props, but I didn't even look to see if the size/pitch is marked on them, but the figures above indicate, "old props".

Last question? Are we having fun yet?

 

[Brian Degulis]

The 60C I bought came from Hat with 1271TIs rated @ 850HP@2300 RPM the engines were set up by Covington. Our 61MY Came from Hat with 1271TIs rated 650 HP @2300 RPM injectors are 90s and the engines were stock DDs. The reason the injectors are hard to find is probably because they're very high output and not as common as the 55 thru 90s. Those props sound small for that HP and size boat what gears are in it?

Brian

 

[Sparky1]

Brian, according to the notes on the paperwork, it has ZF 2:1. The injectors they installed are #7395 on the paperwork but the owner seems to recall Rodger saying they were #7394.

 

[Brian Degulis]

I made a mistake the 60C is 825 HP not 850 and it runs 9215 injectors. The gears are 2:1 ZF and the factory props are 32x34. that's on a heavier 60' boat. The props you mention are small in comparision. The fuel consumption sounds about right.

Brian

 

[Sparky1]

Man, based on this test I posted earlier, these props are WAY too small. We should be turning these puppies way on up there, but seeing as how we've got at least 4 dead injectors, I can see why we aren't.

Take a look at this again for comparison with props and fuel. This test was with 4 blade props, 32x33 which are much larger than our 3 blades. I wonder if that GPH figure at 20 knots was on the pins. Surely not, but it matches up with this test on the 650HP engines. Oh yeah, this boat had new long blocks installed in 2001.

 

[Sparky1]

This prop thing is getting more and more bizarre. I found the "Vital Information" page from the original owner's manual which shows the boat came with 30 x 28, light cup, 3-blade props. I pulled one of the 4-blade props out and cleaned off the barnacles to see it is a 27x25, light cup, 4-blade. Seems to me that neither of these prop sets would be suitable for the boat even at 650HP. Maybe the prop size on that test was listed wrong.

 

[Sparky1]

Rodger called a few minutes ago and will have a dozen injectors in the morning.

 

[captddis]

the currently installed injectors are comprable to the 9215's, that puts horsepower around 840 to 850 hp.

 

[Sparky1]

the currently installed injectors are comprable to the 9215's, that puts horsepower around 840 to 850 hp.

So is that not going to make these props (both sets) pretty much useless with that kind of horsepower?

Seems to me the owner needs to do some prop shopping. I wonder if the guys at General Propeller in Bradenton could offer us some suggestions/props. What about changing the gears in the blowers for more air?

 

[captddis]

check the trans ratio you might have 1.5:1 reduction.

 

[Boss Lady]

Randy,

my prop calculator says that you should be swinging 34x29 three bladed props, for 2350 rpm, 800 hp, and 2:1 gears, max speed at that beam and displacement is 21 knots. I will plug in your current values and see what it says.

 

[Boss Lady]

your current props will only give you 19 knots.

Based upon several prop calculators, I seriously doubt the original 24 knot speed claimed in the brochure. Anyone own one of these puppies with the same power. i redid the calculations giving the most favorable hull type and low prop slip factors and the best speed calculated for this boat with 825 hp at 2350 rpm (brochure said test rpm was 2250) was 23 knots. I think that the speed numbers were fudged.

 

[captddis]

your current props will only give you 19 knots. Based upon several prop calculators, I seriously doubt the original 24 knot speed claimed in the brochure. Anyone own one of these puppies with the same power/

The 650hp 55C will do 23kts. Run the current props with a 1,5:1 reduction and see what you get.

 

[Boss Lady]

prop calculator says 29x23 three blades, and 22.4 knots using 1.5 gears. 17.5 beam, 5 foot draft, 50.2 waterline, 68,000 displacement, 1700 hp, two bearings per shaft.

650 per side says 20 knots.

 

[captddis]

Doing a quick calculation with 1.5:1 gears shows 23.8kt wot and 19.7 cruise with a 29.6X 24.6 WHEEL. My bet is on 1.5:1 gears. A lot of the HP models had them.

 

[Sparky1]

Doing a quick calculation with 1.5:1 gears shows 23.8kt wot and 19.7 cruise with a 29.6X 24.6 WHEEL. My bet is on 1.5:1 gears. A lot of the HP models had them.

This one shows 2:1 as original on the vital's page from Hatteras, but I pulled a little shy of 21 knots with it on Thursday with a light following sea. Can't tell you what RPM I was turning as the tachs on the bridge read as much as 1,000 RPM fast.

Again, it's propped right now with 30x28 as per the original specs. These props were recently re-worked from 30x29. Pulled the survey from June 26 which showed full throttle RPM on port at 2241 with the 4-blades we have onboard. this will a full load of fuel. Port engine reached 201 degrees and climbing causing the WOT portion of the sea trial to be terminated early. Port also smoked during the sea trial above 2100. Starboard reached 2150 at WOT and smoked heavily during the sea trial. I'm hearing bells ringing here.

Something else that seems odd to me is the surveyor listed RPM @ cruise as 1972 on the port and 2022 on the starboard. There are no speed readings on the survey. "No compression tests were requested or performed".

Keep in mind all injectors we replaced after this sea trial. Both blowers on the port were replaced, and blower seals were replaced on the starboard. Intercoolers were also replaced.

 

[captddis]

This one shows 2:1 as original on the vital's page from Hatteras, but I pulled a little shy of 21 knots with it on Thursday with a light following sea. Can't tell you what RPM I was turning as the tachs on the bridge read as much as 1,000 RPM fast.

Again, it's propped right now with 30x28 as per the original specs. These props were recently re-worked from 30x29. Pulled the survey from June 26 which showed full throttle RPM on port at 2241 with the 4-blades we have onboard. this will a full load of fuel. Port engine reached 201 degrees and climbing causing the WOT portion of the sea trial to be terminated early. Port also smoked during the sea trial above 2100. Starboard reached 2150 at WOT and smoked heavily during the sea trial. I'm hearing bells ringing here.

Something else that seems odd to me is the surveyor listed RPM @ cruise as 1972 on the port and 2022 on the starboard. There are no speed readings on the survey. "No compression tests were requested or performed".

Keep in mind all injectors we replaced after this sea trial. Both blowers on the port were replaced, and blower seals were replaced on the starboard. Intercoolers were also replaced.

What do the tags on the transmissions say?

 

[Sparky1]

I'll go check when it stops raining. It's pouring here now.

 

[Sparky1]

Couldn't find anything on the transmissions other than noting a spec plate of some sort had been removed from each of them.

 

[Brian Degulis]

Just check it with a hand held tach engine and shaft and you'll know the reduction.