How would you run it?

[madhatter1]

Heading out for a Keys trip Wednesday in Esperaza, the 46 HP we bought from Captain Dave. 8-92 650HP in essentially new condition and 700 hours on them. Boat was run as I understand it hull speed 50% or more and cruised at 1800 RPM's other time. Most runs are 30-50 miles. Two long runs about 100-130 miles crossing back and forth. Every run we will spend time on plane, 1800 as run before.


Fuel cost is not a factor because this is saved up vacation $. I have not had a real one in years. So those in Sportfishers, what would be recommended for running. More time at cruise or run more at hull speed? Thinking more about what is best for engines and components. LuckyDave is being told run his because the turbo's need heat to be cleaned out. Not sure if that is true or not but does seem to make sense.


We expect to run about 700 total miles. I could honestly run it at hull speed the entire time because it is so pleasant. But the wife is not going to go for that. She gets a little seasick rocking around and would rather just get there.


So expecting nice slow leisurely starts, then run a good bit, and then slow again as we get close to give engines plenty of time to cool back down. I know how Dave ran it, was just wondering how other Sportfish boats are run?

 

[krush]

Run her how she's meant to me run, on plane!

What is max WOT RPM? If it's 2100, running at 1800 is a significant drop in HP required by the props and the engines should be loafing along.

 

[SKYCHENEY]

Dave is the Detroit guru. He's rebuilt more than most here. He knows those engines and that boat. If he gave you advice, adhere to it. I would not doubt his knowledge on this.

 

[oceanjake]

The engines should be run up each day before cooling her down to blow out the coolers of inherent oil which will turn to sludge after it cools, causing an air restriction. Also it’s good for the turbos to spool up, get hot, and burn out carbon that can cause them to seize up in the housings over time. Outside of those things, engine life can be calculated by fuel burned per cylinder. I’m not sure of your pocketbook, but throwing 4 times the fuel through the engine to run on plane will result in 25% of the life of a hull speed engine. I’m sure some will disagree, but that’s my understanding and also a factor in how I run my 60 EB.

 

[jim rosenthal]

You don't mention if the boat is equipped with boost and EGT gauges. If it is not, then I would experiment and see what your range is on planing speeds- get her up on plane and then throttle back while still keeping her up on plane. My guess is that will be about 14-16 knots with that boat.

However, if she IS equipped with boost and EGT gauges, then I think you should run the boat based on what they are telling you. I run my boat looking at the EGT and trying to keep it under 950, which usually means about 20 knots, but it isn't the same hull and engines. I look for about 10-12 pounds of boost on each side. This seems to be where the engines are happiest. You might look on Tony Athens' web site, sbmar.com, I think it is, for discussions about boost, EGT and best engine speed.

Also, the engines work the hardest when in the transition zone between displacement and planing, so it is best to get through that speed zone and up on plane promptly, and not linger in it.

 

[doc g]

For us it depends on sea condition, I run slow ( 950 rpm/9.7 K)when we have the time at hull speed. If need to get there or the seas are rough we run at slow cruise ( 1850rpm/19.4 K). This is in a 74 sdmy with Cats...................Pat

 

[madhatter1]

Boat cruises at 20 kts @1800 RPM. 23 or so MPH. So moving along pretty good. Although it is true that gallons consumed is a fairly accurate indicator of engine life reality is that pleasure boats rarely even if used often ever burn enough fuel to wear them out. Commercial boats get thousands of hours of use due to the fact they are run constantly and not just sitting in the salt air. Granted commercial boats run lower HP to get these hours than a pleasure boat will run.

We limit engine life more by lack of use or running too hard than anything else. Was just wondering if running too light is also an issue and if so does heating them up un a good run limit or correct this. I have searched for power curve on these and found nothing but 1800 RPM should be a safe HP to run them at. If Dave ran them there you can bet it's very safe. But again question is not safe cruise RPM, it's cruise VS hull speed mix of time.

Tomorrow is the big day. We head South!

 

[Fanfare]

Just spent March and April in Key West. The Stock Island Marina may be the best marina I have encountered for great staff, cleanliness (power washed the trash containers), even pumping out our tiny 25 gallon holding tank daily! Very sheltered harbor with floating docks. Very quiet locations, Perry Hotel on premises with great food, pool. Free hourly shuttle to/from downtown Key West should you want more action. Roostica Restaurant and Hogfish Grill nearby, and an excellent French bakery made it a great place. We are already booked for next year!

We had an unusual favorable five day weather forecast for the end of February. Ran outside from Ft. Lauderdale to Key Largo (Anglefish Creek) on plane. Then decided to take it easy by running Intracoastal down to Islamorada and Marathon. We draw 4 ft. and generally kicked sand most of the way. Never touched but I would not consider running fast here--frequently too shallow. It's a long way around to Key West from there so went back outside to Hawk Channel, ran on plane to the Stock Island Marina. But the Intracoastal is fine if it gets rough. Just remember that the Overseas Highway to KW is built over the old Florida East Coast railroad bed and there are not all that many places a yacht can pass from the ocean side to the gulf side of the Keys due to the old low bridges.

 

[luckydave215]

Guys, keep in mind the advice I was given by a Detroit guru was for MY engines, which are the (stupidly) hot rodded version of 12v71ti in a tournament rigged sportfish.
Covington put in giant injectors, NA pistons, 92 series turbos, and a few other tweaks like modified timing etc.
All in the name of speed, which in my opinion is a fool's errand on a 60C.
Hatteras built just two boats like this, open bridge, half tower, 1000 hp per side with 1.5:1 gearboxes, beefed up bow section, one piece shafts, and several other mods that may or may not make a difference.
Roger Wetherington told me they were the fastest 60C's built and ran 25 knots in the river behind the plant with the props they had then (32'x32' sand cast Michigan wheel), mine runs 27kts with much better 33'x31 ZF 5 axis machined props.
I wouldn't apply the advice I got for my engines to any others without careful thought.

 

[madhatter1]

Luckydave, I would be nervous just starting those engines! But as for being a fools errand maybe so but remember they were built by men and at one point “ It seemed like a good idea at the time”!

 

[jim rosenthal]

Dave, what was your source for the wheels? I have wondered often whether my boat would perform better with high-zoot wheels like those ZFs, or Australs...

 

[Boatsb]

I've talked to acme about props forna customer. Nice product and in line with or coat a little less than the veem conquest.

I'd like to work out a test if your interested. They seem to sell in some areas and have no one promoting them in others.

 

[Scarlett]

Dave’s engines not only sound great they do not smoke at all on start up, truly amazing. John

 

[krush]

Dave, what was your source for the wheels? I have wondered often whether my boat would perform better with high-zoot wheels like those ZFs, or Australs...

One day I will play with new wheels. Read this thread, the results are amazing. https://www.thebassbarn.com/forum/6...55242-38-henriques-huge-performance-gain.html

 

[luckydave215]

I would be nervous just starting those engines!

Maybe. Nonetheless they have run perfectly without a hint of trouble in the 14 years we have owned her. This stuck turbo is the first issue....ever.

 

[luckydave215]

Dave, what was your source for the wheels? I have wondered often whether my boat would perform better with high-zoot wheels like those ZFs, or Australs...

I sourced mine through a local dealer that is no longer around. ZF engineers came on a sea trial after placing sensors on everything. No variable was left un measured.
The new wheels were designed using computational fluid flow analysis, (vs eyeballs and a grinder on a wood form at Michigan Wheel) then 5 axis CNC machined from an oversized (thick) silicon aluminum bronze forging in Australia. ZF didn't charge me for the engineering cost, I believe they were trying hard to penetrate the north American market at the time.
When they showed up all the yard guys had to have a look see. They really were a thing of beauty.
The final shape is 33"x31" four blade, 89% blade area KCA skew series blade shape.
The difference in performance was amazing. We were shooting for more efficient slow and medium cruise speeds - up to 18 knots. There was a lot of blade slip with the standard wheels, that's what we were going after, that and the vibration with the crudely made sand cast Michigan wheels.
The increase in top end was a surprise.

 

[jim rosenthal]

I keep thinking about it. I've forgotten what's down there, now- I know they were tuned up by a Propscan shop a few years ago when we did the new cutlass bearings, and the shafts were straightened a bit at the same time. A higher cruise speed would be great, though...