Air Controls on Boats-just info

[TomC]

I was on a converted oil crew boat SCUBA diving off Bahamas a few years ago. The 90ft boat had triple 12V-71TTI's (twin turbo and intercooled), 2 2-71 generators and 2 7.5hp air compressors.  I asked the captain how many batteries he had, and he said 2 8D's-one to start one of the generators and the other as an emergency standby under the pilot console for powering the radio.  All other controls were done with air pressure.  To start the boat cold, you would electrically start the generator, then fire up the air compressors. When pressure was up, all three main engines had air starters, air throttles, and air shifters.  The second generator also had air starter. 

With a boat, if any of the mechanical or air throttles went south, you could have a crew member in the engine room operating the shifting with a big wrench, and running the boat throttle with a piece of rope tied to the governor getting instructions from the captain on a walkie.  Can't do that on a bus.

Just a side story-the captain told me they came back from a long weekend to fire up the boat.  The generator battery was to low to turn over the engine-but had some juice.  So they took a piece of rope and wrapped it around the crankshaft pulley and two crew members pulled and the other hit the starter to get it going!  I don't think you could do that on anything other then a 2 stroke Detroit!  Good Luck, TomC

[chev49]

Looks like the rope is the most crucial component of the system...

[c-coop]

I saw one better than that, went onto a shrimp boat with a 6-71 engine which didn't have a starter on it. Asked them how they started it. He removed the valve cover and placed a piece of hacksaw blade under each rocker arm, wraped a rope around the front pulley, one man pulled the rope and another pulled the blades one one cylinder, as soon as it started to run the pulled all the others and installed the valve cover. Said they been doing this for years

[HB of CJ]

I bet that boat sounded soosss cool.  Neat method of starting that pesky DD gen set.  FWIW, way back in 1975, we dumb firefighters bump started old, old Ladder Truck #1, which had an 8V71N running through a T905M.  Seems somebody shut the engine off and all the running red lights and stuff ran down the starting batteries.  Sossss, about 10 of us just pushed the old girl to bump start her.  Don't ask who shut down the mill and FORGOT to hit the batt disconnect switch.  Embarrassing.  HB of CJ (old coot)