Wartsilä 12V25F, fishing vessel

[Mohamed lah]

Salam Alaykom dear all,

Hope all is going very well.
Ref to above subject, please we have an issues on board our trawler vessel.
When we engage the Propeller, the engine reverse by itself!!!
We kindly ask you, if some one have the same situation?? We need the points and items/parts to be checked?!
Type of engine Wartsilä 12V25F.
Thanks you in advance

Slts/ Best Regards

 

[TugboatEng]

Please fill us in on some additional details:

Pneumatic or electronic control?
Direct reversing or marine reversing gear?
Controllable pitch propeller?

What does it mean to engage the propeller? Is that clutch in ahead? What happens when you clutch in astern?

 

[boo1]

consider contacting the manf

 

[enginesrus]

I think that is a 4 stroke so it needs a transmission for reversing. So something wrong with the control system for that, or the transmission it self.

 

[TugboatEng]

enginesrus, marine reversing gears only cover the lower horsepower range. Larger engines, including 4-strokes, are direct reversing. Cam timing is shifted to facilitate reverse rotation.

 

[itsmoked]

I fear they've gone down with the ship.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[enginesrus]

What is the HP cut off point? From what I see this is an under 4000HP engine. I am aware that a 4 stroke diesel will reverse, even with out reversing cam timing, been there done that years ago on an off road machine by accident.
Black smoke blowing out the air filter, forward gears made it go in reverse, yes pretty crazy.

 

[LittleInch]

Engines going backwards eh? I never knew.

When I was about 5 I thought my Dad putting the car into reverse stopped the engine and made it go backwards, but never knew that's what actually happened!

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[TugboatEng]

The horsepower cutoff is an obsolete definition. Going into back to the 1940's it was true that about 1500hp was leaving the realm of reversing gear and entering the realm of direct reversing. Today we have high speed engines making 4000-10000 horsepower and direct reversing is not so common except in very large engines.

 

[itsmoked]

I'm betting they use reversing props with those?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[TugboatEng]

Controllable pitch props are certainly gaining popularity. In dynamic positioning they allow for faster thrust reversal. You'll even see controllable pitch in z-drives. For towing and anchor handling, CP let's you dial the prop in so you can maximize the power your prop outputs. Applications that exceed marine reversing gear capabilities but are not direct reversing will also use CPP. Caterpillar C280-16 is an example of such an engine.

 

[itsmoked]

Cool. Thanks for the info.

Keith Cress
kcress -

http://www.flaminsystems.com