Engines, Engine Controls and Exhausts

May 12, 2017


The catamaran is powered by two Cummins 270B diesel engines which deliver 270 HP in order to have an adequate power reserve.

The engine delivers its maximum power at 2600 RPM and with the ZF gear box with a 1 to 3 gear ratio the propeller turns at a maximum of 866 RPM.

The Cummins engines are turbocharged with jacket water aftercooler.  Mainly for fuel efficiency but also to conform with the NOx requirements of MARPOL 73/78, annexVI, regulation 13 as applicable.

The exhaust is a mixed "dry and wet" type exhaust, that is the engine cooling water is injected into the exhaust manifold to cool the exhaust gases above the engines, thus avoiding to have to lift the water exhaust mixture. The size of the exhaust is 125 mm ( 5").  To keep the exhaust hose as short as possible and prevent the fumes from being sucked back the exhaust discharges over the external side, at the knuckle, pointing downwards.

The engine controls (throttle and gear) are of the electronic type, the ZF MicroCommander.  Electronic engine controls give an added safety to the operation of the engines since it is not possible to damage an engine gear by shifting too fast or with the engine not idling.

Refer to the Engine DC electric system for the electrical circuits of the engines.



Exhaust High Temperature Alarm

If the exhaust high temperature alarm on the engine instruments goes off, immediately shut down the relevant engine. Failure to do so will cause a meltdown of the exhaust silencer and its connecting hoses and engine overheating, with catastrophic results. 

Check the water strainer to see if it is clogged.  If it is, clean and check that the water entrance is not obstructed by foreign materials like plastic films or seaweed.  If that seemed the case, let the silencer cool down and restart engine and immediately check if cooling water is discharged overboard.

If the water inlet and or strainer are OK the possible cause may be a failure of the raw water pump impeller, which has to be checked and substituted.  Consult the engine manual for instructions on how to change the impeller.


Other Engine Alarms

If any other alarm on the engine instruments goes off, immediately shut down the relevant engine.  Failure to do so can cause serious engine damage.  Consult the engine manuals for further instructions.



To winterize the engine when the catamaran is on dry land and freezing temperatures are expected proceed as follows.  This procedure can also be used to clean the engine from salt water.  Two persons are necessary for this operation.

Disconnect the engine raw water inlet hose from the strainer and insert into the inlet hose a suitable piece of hose that terminates into a bucket placed on the outside of the engine room.  The bucket must have a capacity of at least 15 liters.  Fill the bucket and the engine raw water hose with fresh water and start the engine.  While the engine runs continue to fill the bucket with fresh water.  Normally it is not possible to supply enough water to keep the engine running for more than a few seconds.  When there is no more water left, shut down the engine. 

Fill the bucket and the engine raw water hose with a 50% mixture of anti freeze and water and start the engine.  Observe the engine exhaust and turn off the engine immediately the anti freeze water mixture starts coming out.  This is easily seen thanks top the green color of the anti freeze.  About 15 liters of anti-freeze water mixture are needed.

Empty all the water from the sea water strainer.  Do NOT add anti-freeze to the sea water strainer, since it will turn the strainer brittle.

Performing this operation the plastic silencers will also remain filled with an anti-freeze water mixture.  Although Vetus Italy says that the anti-freeze will not harm the silencer, I think that it is best to remove it if it stands for a long time.  To do so disconnect the plastic hose that runs from the silencer to the PSS shaft seal, on the side of the seal and connect a fresh water hose to the plastic hose that goes to the silencer.  Turn on the water and observe the engine exhaust.  Let the water flow until clear water comes out. 

Reconnect all the hoses.

Caution.  The green-blue glycol anti-freeze is a very poisonous substance.  Handle with care.




Check the engine oil level daily or every  20 hours.
Check the coolant level daily or every 20 hours.
Change the engine oil and oil filter every 3 months or 250 hours.

When new, change the gear box oil after 50 hours.
Check the gear box oil level weekly.
Change the gear box oil every 12 months or 1,000 hours.

Twice a year lubricate the Marelon throughhull valves with Lanocote or any quality waterproof grease.

To get to the thermostat it is necessary to take off the alternator.  It is situated in the front, on the right side of the engine, under the big black cooling water hose.  Not the easiest place to get at.


The oil pressure sender is situated on the fuel in-out plate. When it was broken the instrument showed high, out of scale pressure. 

The one and only engine zinc is under the right hand side cooling pipe and has to be checked frequently, at least twice a season.
The engine zinc needs a 24 mm spanner.

The nuts of the engine supports necessitate a 28 mm spanner.
The nuts and bolts of the exhausts necessitate a 10 mm spanner.
The nuts of the constant velocity joint necessitate a 24 mm spanner.


Raw Water Impellers

The raw water impellers are difficult to change, especially the one on the starboard engine.  Even when using the engines for 200-250 hours each year practice has shown that it is necessary to change the impeller every year. It is best to remove the salt water pump from the engine every year and then change the impeller and if necessary rebuild the pump with  the minor or mayor kit.  Removing the salt water pump has the additional advantage to let you inspect the ceramic seal to the bearing, which shows wear after a few years.

Impellers, even if good, after having been in salt water should, according to Claudio, a marine mechanic of Porto Levante, not be used again, since they could be brittle.  To keep them as spares they should be kept in a bag with antifreeze solution.

All in all it seems that the raw water pump is the most delicate part of the engine.

To remove the pump you have to disconnect the raw water hose.  It is best to first remove the hose from the strainer and then lift out the pump.

Consult the engine Operation and Maintenance Manual for further instructions.




January 31

Started both engines.  Problem starting port engine since the starting battery was down.
Blew two 250 A fuses. Starting batteries are now exactly 10 years old.  Old age symptoms?
February 14 Port engine 437.6 hrs.  Starboard engine 357.78 hrs. in Porto Levante. Started both engines and generator.
April 11 Port engine 440.1 hrs.  Starboard engine 360.4 hrs. in Porto Levante.
  Checked oil of both engines.  OK but kind of black
April 16 Port engine 446.3 hrs.  Starboard engine 366.5 hrs. in Porto Garibaldi.
May 20 Maintenence performed by Claudio.
  Port engine 450.8 hrs.  Starboard engine 371.0 hrs. in Porto Levante.
Did not change impeller.  Engine zinc completely used up.
Starboard engine changed oil and cleaned air filter, very dirty.
Changed impeller, is in good state.
Lifted the engine.  Engine zinc completely used up.
June 8 Port engine 463.1 hrs.  Starboard engine 380.3 hrs. in Porto Levante.
June 9 Port engine 470.8 hrs.  Starboard engine 388.0 hrs. in Rovigno.
June 15 Port engine 490.9 hrs.  Starboard engine 408.0 hrs. in Mir, Dugi Otok, Telascica.
Oil, water, fuel filters OK.
June 19 Port engine 500.4 hrs.  Starboard engine 417.5 hrs.
June 23 Port engine 520 hrs.  Starboard engine 436 hrs. Vela Luka anchorage.
June 24 Port engine 522.9 hrs.  Starboard engine 423.2 hrs. Lastovo island. 
June 26 Port engine 527.6 hrs.  Starboard engine 442.9 hrs.Korcula anchorage. 
July 16 Port engine 582.81 hrs.  Starboard engine 497.4 hrs.Preveza, Greece.
August 7 Port engine 653.71 hrs.  Starboard engine 559.89 hrs.Rocella Ionica.
  Changed engine zincs.  Very necessary.
September 9 Port engine 812.4 hrs.  Starboard engine 712.7 hrs. Porto Levante.



July 7  


March 13 Port engine 1318.5 hrs.  Starboard engine 1217.58 hrs. in Genova Porto Antico
  Started starboard engine after turbo overhaul
  Changed oil and all the filters
  Starboard exhaust brought to Arolo, checked and welded a reinforcement

Starboard heat exchanger cleaned and repainted by Motonautica Angerese.

May Port salt water pump bearing shot.  Motonautica Angerese rebuilt pump with Sherwood mayor kit.

Changed impeller of the starboard pump with the Sherwood replacement impeller.

July 11 Port engine OK, Stbd engine had to add 1l oil
July 21

Port engine 1363.41 hrs.   Starboard engine1262.41 hrs. in Porto Azzurro Elba;

  Checked both engines oil level.  Both OK
  Added about ˝ liter of oil to the starboard gear.

October 26

Started both engines and let them run for 15 minutes.  Genova Porto antico.


February 4

Port engine 1391.35 hrs.  Starboard engine 1290.36 hrs.
  Started both engines and let them run for 15 minutes.
March 4 Port engine 1391.99 hrs.  Starboard engine 1291.00 hrs.
  Started both engines and let them run for 30 minutes.
April 2 Reinstalled port exhaust after checked and welded reinforcement in Arolo.
April 30 Port engine 1393.00 hrs.  Starboard engine 1292.00 hrs.
  Changed oil and all the filters.
  Changed the engine zincs.  Very worn.
August 25 Port engine 1489.00 hrs.  Starboard engine 1388.00 hrs.
October 30 Started both engines and let them run for 15 minutes.
December Cleaned port SS pipe between turbo and air intake.
  Removed port oil pressure sensor.  Changed the port engine oil and the filters.
  Replaced the complete port sea water pump with a rebuilt one.
  Port heat exchanger cleaned and repainted by Motonautica Angerese.  Changed zinc.  Not too bad.
  Port engine 1499.58 hrs.  Starboard engine 1398.04 hrs.
  2015 total engine hours: Port engine 108.23 hrs.  Starboard engine 107.68 hrs.



Port engine 1499.58 hrs.  Starboard engine 1398.04 hrs.
March Replaced the port oil pressure sensor.
  Replaced the complete starboard sea water pump with a rebuilt one.  Ceramic seal shows wear.
Impeller looks OK, but is not to be trusted.
  Changed the starboard and port engine oil and the filters.
October Port engine 1628.76 hrs.  Starboard engine 1525.42 hrs.
  Started both engines and let them run for 15 minutes.
  2016 total engine hours: Port engine 129.18 hrs.  Starboard engine 127.38 hrs.


February 25

Port engine 1628.76 hrs.  Starboard engine 1525.42 hrs.
  Started both engines and let them run for 15 minutes.
April 11 Port engine 1627.74 hrs.  Starboard engine 1526.08 hrs.
  Changed the starboard and port engine oil and the filters.
  Changed the engine zincs of both engines.  Completely worn.



Engines and Gear Box

Cummins 270B


Power rating for use in variable load applications where full power is limited to 1 hour out of every 8 hours of operation.  Also, reduced power operations must be at or below 200 rpm of the maximum rated rpm.   This power rating  is for pleasure/non revenue generating applications that operate 300 hours per year or less.

The reduction gear has a ratio of 1:3 and is manufactured by ZF in Italy.

270B with ZF gear box  
Crankshaft power 194 kW 270 hp  
Rated speed 2600 RPM 2600 RPM  
Bore x stroke 102x120 mm 4.02in x 4.72 in  
Displacement 5.9 liters 359 cu in  
Aspiration Turbocharged Turbocharged  
Number of cylinders 6 6  
Engine weight without gear 517 kg 1138 lbs  
Engine oil capacity 15 l    
Engine oil type SAE 15W - 45    
Gear box oil capacity 5 l    
Gear box oil type SAE 15W - 45   same as engine
Cooling water capacity 20.6 l   50% water - antifreeze
Dimensions without gear  
Length 1041 mm 41 in  
Width 816 mm 32.15 in  
Height 771 mm 30.4 in  
Fuel consumption (Cummins data)  
RPM liters per hour gallons per hour kg per hour
2600 56.8 15.0 45.9
2400 42.4 11.2 34.3
2200 32.3 8.5 26.1
2000 24.7 6.5 20.0
1800 18.5 4.9 15.0
1600 14.5 3.8 11.7
1400 11.0 2.9 8.9
1200 7.8 2.1 6.3
Measures from the 0 base line  
Height of propeller shaft 550 mm    
Height of engine shaft (gearbox input shaft) 685 mm    
Height of engine support (engine mount blocks included 681 mm    

The LOW oil mark on the dipstick is with 12 liters of oil in the oil pan and the mark is 35 mm from the end of the dipstick.
The HIGH oil mark on the dipstick is with 14 liters of oil in the oil pan and the mark is xx mm from the end of the dipstick.
The total oil capacity of the engine is 15 l.

The fresh water cooling circuit holds 20.6 l of a 50% water antifreeze mix.

For the calculation of kg per hour fuel consumption a specific gravity of 0.81 was used for the fuel.
At max. RPM the fuel consumption is 170 g/hp hour.  These are Cummins data.


  Engine 1 (Port) Engine 2
Engine serial no. 46396235 46389989
Engine model name 6BTA5.9M1 6BTA5.9M1
Gear box type ZF 280-1 ZF 280-1
Gear box serial no. 20052409 20052408
Gear box part list no. 3207002057 3207002057


  Engine 1 Engine 2
Oil dipstick LOW oil level 57 mm 35 mm
Oil dipstick HIGH oil level 69 mm ??
Oil filter hoses length standard 190 cm
Throttle cable length 10'(305 cm) 11'(335 cm)
Gear cable length 7'(213 cm) 9'(274 cm)


Raw Water Pump

The raw water pump is manufactured by Sherwood.

The engine raw water impeller is Cummins # 389 733 700.
Also manufactured by Sherwood (www.sherwoodpumps.com) 17000K - SHW

At the sidesof the water pump there are two o-rings , each with an ID of 50 and OD 56 mm.


Sherwood pump

Sherwood impeller


Sherwood raw water pumps  


Oil Pressure Transducers

The oil pressure sender is situated on the fuel in-out plate.

Oil pressure transducer

It is manufactured by VDO and made in Germany.


Cummins oil pressure transducers  Cummins # 3917123 

Cummins Italia S.p.A.

ZF Padova SpA

The following manuals provided by the engine and gear box manufacturer are also part of this section:

Cummins 270B Cummins Operation and Maintenance Manual
Cummins 270B Cummins B-Series Aftercooled [Family M10TA] Technical File
Cummins 270B Cummins B/C Series Marine Engines Installation Directions
Cummins 270B Cummins Engine Mounts Manuals


ZF 280 Family Gearbox ZF Gearbox Manual 


Sherwood Pumps Technical Guide


Oil Filters

The oil filters of each engine have been moved from the engine body to the engine room wall with two oil proof hoses.

Engine oil filter

 Be aware that the removed filters are not the regular Cummins oil filters but are a different Cummins type and are not exchangeable.  The screw on threads are different.


Fleetguard - Cummins lube filters LF 3959


Engine Sacrificial Zincs

Each engine has only one sacrificial zinc, under the right hand side cooling pipe.
They are Cummins straight thread.  The head takes a 21 mm spanner and is 24 mm long.
The zinc (minus thread) is 52 mm long and has a diameter of 16 mm.


Cummins engine zinc  



The two alternators are not Cummins originals but Canadian substitutes.

Each alternator outputs 130 A.

When working on the alternators make sure that the output cable is firmly screwed on the bolt.

Purchsed November 26, 2008 in Taglio del PO (RO).

  Engine 1 Engine 2
Alternator model 42785 Serial # 06U8C012 Serial # 06U8C019



The exhaust is of the dry-wet type and custom manufactured by carpenteria Acerbis.

Acerbis Carpenteria srl

Port exhaust wear

Port exhaust wear.  Was fixed by applying a SS patch.


Silencer and Exhaust Hoses 

Vetus provides the silencer and hose for mix of exhaust gases and water.

The silencer is made of synthetic material and therefore does not tolerate high temperatures.  The silencer is equipped with a temperature probe that activates an alarm on the bridge if the water gas mixture exceeds an acceptable level. 

Vetus Italy states that you can leave an anti-freeze water mixture in the silencer for the whole winter, but I am not so sure.


Vetus horizontal silencer Type MV, OD 125 mm
Vetus SLANG exhaust hose 127 mm I.D.

Vetus Italia srl

The following manual provided by the manufacturer is also part of this section:

Vetus Vetus Exhaust Silencer Manual 


Engine Cooling Water

There is a dedicated engine cooling water inlet on the outboard side of the hull, protected by a Marelon ball valve and a water strainer.

The flanged valves are bolted to a flanged piece of aluminum welded to the hull.  An O ring provides a seal between the two flanges.

Forespar's line of valves offer great strength, light weight, and complete freedom from corrosion and electrolysis making them the ideal valve for controlling inlet and outlet water requirements above and below the waterline. They are precision molded and then machined from high strength, glass reinforced MarelonŽ and incorporate TeflonŽ seals for long-life, trouble free operation.

Make sure that the valves are in the closed position when the engine cooling water is not in use or when leaving the boat unattended.

Lubricate twice yearly with Lanocote or any quality waterproof grease.


The water strainer is made of clear plastic, which makes checking flow easy.  The nylon filter basket can be removed without tools for cleaning.  Threaded 1 1/2" female inlet and outlet ports.

Do not add anti-freeze compounds to the water strainer.  They will cause deterioration of the plastic, causing it to crack.







 From the strainer a water hose goes directly to the engine raw water inlet.


Forespar Marelon flanged ball valves Forespar 904011, 1 1/2


Raritan Raw Water Strainer Raritan # RWS
West Marine 316390


Vetus MWHOSE water hose 51 mm I.D., 61 mm O.D.

Forespar Products Corporation

Raritan Engineering Company, Inc

Vetus Italia srl

The following manuals provided by the manufacturers are also part of this section:

Forespar Forespar Valves Manual 
Raritan Sea Water Strainer Manual 



ZF MicroCommander Engine Controls

The gear and power on the engines are controlled by the ZF MicroCommander  electronic system.  The system consists of a main station on the bridge, a handheld remote control connected with a cable to the unit and a main contol unit in each engine room.

The handheld remote also controls the rudders with the switch on the botton.

The handheld unit is equipped with a safety lanyard.  The handheld system will not operate if the lanyard is not attached to the unit.  The lanyard is to be worn around the operator's wrist during handheld operation.   In the event the locking key is pulled from its socket the engine speed will reduce to idle and the clutch will shift to neutral.

The MicroCommander is powered by the auxiliary key on circuits of the engines.  An automatic power selector selects the best power source for both units.  Two breakers, one for each processor, are located in the starboard engine room.  Both breakers must always be on.


The operation of the MicroCommander is explained in the manuals (see below) supplied by the manufacturer.


MicroCommanders control head # 65513B
2 MicroCommanders processors # 39602Z
MicroCommanders handheld control # 61860Z

The wiring on the port side control is standard, as pictured above.  Unfortunately the wiring on the starboard side of the control uses a different colored cable, like this (jumpers not specified):

Port Starboard
1  Black 1  Black
2  Brown 2  Brown
3  Red 3  Red (big)
4  Orange 4  Pink
5  Blue 6  Green
6  Green 7  White
8  Violet 8  Gray


ZF Mathers, LLC


The following manuals provided by the MicroCommander manufacturer are also part of this section:

ZF Micro Commander Quick Start Manual
ZF Micro Commander Operation & Troubleshooting Manual
ZF Micro Commander Installation Manual
ZF Micro Commander Handheld Installation Manual
ZF Micro Commander Power Selector Manual
ZF Micro Commander MC2000 Series Standard Control Head Variations


Gear and Throttle Cables

The gear and throttle cables are manufactured by Teleflex cables of various length (see engine specifications above for used lengths).  They have an inner core that's encased in nylon and travels back and forth in a high-density polyethylene liner.  Tight 4" minimum bend radius.  10-32 SAE threads.

Teleflex control cables 33C Supreme Red-Jacket

Teleflex Marine
Purchased through West Marine


Engine Room Blowers

The engine room blower can be turned on to dissipate heat or change the air in an engine room.

The blower can be turned on at the engine room entrance or just inside the engine room.
The breaker is situated on the hull panel


Jabsco continuous duty blower 4 Jabsco 35760 - 0092 

Jabsco Industries

The following manual provided by the manufacturers is also part of this section:

Jabsco  Jabsco Blower Manual




Marine Engines Rating Guide Cummins September 2000




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