Throttle settings

Always like the parts in movies where the ship's telegraph goes "clang, clang" ordering and acknowledging engine changes. Old-time merchant ships typically had dead slow, slow, half, and full speed settings while military types had one-third, two-thirds, standard, full, and flank speeds. ...

For what it's worth, here are mine:

800 RPM: idle, dead slow, one-third. Used when shifting the transmission and, usually with periods of neutral, close-in maneuvering. [3.3 knots @ 0.4 gallons of fuel per hour]

1000 RPM: no wake. [4.2 knots @ 0.6 gph]

1400-1600 RPM: slow, two-thirds (easy cruise). Use when a higher speed will get me there too soon. [5.7-6.0 knots @ 1.2-1.5 gph]

1800 RPM: standard (normal cruise). Engine sounds happiest, and this is the setting used 80 percent of the time. [6.4 knots @ 1.7 gph]

2200 RPM: full speed (hard cruise). Used when the most speed is important or fighting a strong adverse current. [7.1 knots @ 2.9 gph]

2400 RPM: flank speed, wide-open throttle. Used only for testing. [7.4 knots @ 4.0 gph]

Boat weighs 14 tons, has a 31.6-foot waterline, and about a 12-foot beam at waterline. Engine is a normally-aspirated John Deere 4045, 80-horsepower diesel engine.

You forgot "goin home turns". Thats when the throttleman would answer a standard bell with 125 turns instead of the required 120 turns.

That's six named speed for a 4.1 kt speed spread. We only had a few more than that in a Learjet 60 with a 460 Kt speed.

Twin 6BT5.9M 210 HP Cummins
650-700 RPM: idle, dead slow, one-third. Used when shifting the transmission and, usually with periods of neutral, close-in maneuvering. 4 knots
1000 RPM: no wake. 5.1 knots
1650 RPM: cruise. 7.5 kts 3.5 gph run here 95% of the time
1800 RPM: 7.9 knts
2000 RPM: 10 knts
2200 RPM: 10.5 Knts run here when conditions are rough and i need to get home
2600 RPM: flank speed, wide-open throttle. 11.9 kts

800rpm Idle.
1200rpm. High smooth idle.
1400rpm. Slow speed arriving or departing harbor, no wake
zone, engine warm up ... ect.
2300rpm. Usual cruise rpm. 6.15 knots. About 80% of engine time.
2500rpm. Everyday high speed continuous cruise. 6.4 knots
2800rpm. Maximum continuous power per Mitsubishi.
3000rpm. WOT for testing or temporary emergency power.

650 RPM - idle and till clear of marina
1650 RPM - 6.3 knots -Cruise (everywhere unless very close aboard to a tippy boat or past marine LEOs
? RPM Full Throttle for troubleshooting

I gave up the whole engine order telegraph bell thing when my kids complained about spending the whole trip in the engine room holding the throttle.

I now use Kobelt cable controls and find maneuvering in the marina much easier with way less allisions.

Digital tacks

My boat has digital tackometers, throttle settings, slow and slower.

Twin Volvos, with digital tachs and running the measured mile:

1200 rpms 5 kts.
2450 " 8.5 kts. cruising speed
3400 " 11.6 kts. maximum speed

Diesels don't have throttles. Just saying.

Apparently, Winter is dragging along too long for some folks.

Detroit 8V71N

600 rpm - Ramming speed, used to feel my way into the slip, amuse bridge tenders. irritate lock masters and scare the local fuel dock lady.

1200 rpm - Normally used when lost. Perfect for large circles.

1600 rpm - Normal cruise, giving a speed allowing you to easily catch up to, but not enough somehow to pass, large tows.

1800 rpm - Used for the first two days after pension check hits the bank.

2200 rpm - Used by mechanic during sea trials

2400 rpm - Only ever used once during a moment of abject terror, when a sailboat exercised his right of way with a totally unexpected and in my view, unnecessary maneuver.

WesK said:

Apparently, Winter is dragging along too long for some folks.

Click to expand...

It certainly is.

Dimer, that was a keeper.

fryedaze said:

You forgot "goin home turns". Thats when the throttleman would answer a standard bell with 125 turns instead of the required 120 turns.

Click to expand...

you got that right,been there done that more than once

I was on the USS Los Angeles many years ago and asked about the speed settings on the annunciator (?). Above Flank there was "Emergency" and "BS". I asked the ET showing me around how fast "BS" was and his response, "Slightly less than turns for home."

Tom

BS is "battle short". Safety shutdowns disabled. Plant can be run as hard as it can take, or more.

Ski in NC said:

BS is "battle short". Safety shutdowns disabled. Plant can be run as hard as it can take, or more.

Click to expand...

Some guys called it SUBROC speed. Because that is how fast you want to go in the other direction after you shoot one.

I think this is why.

My former trawler was 36 ft. with a single engine. Throttle settings were "on" and "off."

Many people appear to be shy about disclosing their typical RPM settings and their fuel consumption rates.

My boat weighs around 58,000 pounds when it's loaded. It's 61.5' LOA and has a LWL around 50'.

For what it's worth, here are my numbers:

800 RPM: idle, dead slow, one-third. With mine, at 800 rpm's I'm doing about 8.5kts. This is a bit below hull speed. I don't really have a no-wake speed unless I take it in and out of gear.

1000 RPM: no wake. 10.5kts. This is close to hull speed and a very comfortable "slow cruise" speed for when we're not in a hurry to get somewhere. .

1400-1600 RPM: slow, two-thirds (easy cruise). I almost never run at this rpm range because it's too inefficient for my boat.

1750 RPM: standard (normal cruise). This is 80% of WOT throttle and (depending on load--water/fuel, etc.) we're cruising around 22-24kts. We cruise at this rpm if we're heading somewhere and don't want to dawdle. The boat really likes this as a fast cruise speed. The Cats are humming and the boat rides and handles well.

2150 RPM: flank speed, wide-open throttle. I don't run at this rpm range because we're burning ~65gph. We're cruising right at 30.1-30.3kts. The boat really likes this speed. I really don't like the fuel consumption so we don't do it often.

x2