+++NCR MCR question+++

[mhdsharifi]

hello every one:
How can tel me what means NCR , MCR and Sea margine and have a compare betwen them.
thank so much
bye

[DaveB]

I think that they are

NCR - Non Continuous Rating : max can run engine at for brief period

MCR - Manufacturers Continuous Rating : recommended maximum engine operating load for extended periods

Sea Margin - similar to operating allowance : increase to allow for seas and wind, typically 5-30% depending on operating location

[RANCHI OTTO]

MCR > Maximum cont. rating > Max. power for short period
NCR > Normal cont. rating > Cont. power for all time long

For engines like MTU, the NCR = MCR with no power losses for tropical conditions.

Sea Margin > Normally the speed guarantee is valid for wind B2 , clean prop's and hull. In operating conditions You have to add local sea and wind conditions. It is better to calculate your propeller characteristics with the RBH +Rapp + Raa + Rw where
RBH > Bare hull resistance (estimated or from tank tests)
Rapp > Appendages resistance
Raa > Wind resistance B2
Rw > Waves resistance (calculated for various sea state)

This is important because you calculate the propeller's pitch with a margin in order to not overload the engines in bad weather conditions.

RANCHI Otto

[mhdsharifi]

tank you ranchi (and also dave b) so much
ranchi! my question is for low speed engines (i dident find a spesial web site for merchent ship to write my qustion on there )
what about other engine like manb&w or wartsila (compare between NCR and MCR)
tanks again
m.sharifi

[RANCHI OTTO]

Normally the continuous speed is correponding to 0.85 x MCR for low speed engines.

[RANCHI OTTO]

To calculate the pitch of the propeller don't forget to increse it by 3/3.5% in order to have some margin in rough sea. So doing the engines are not overloaded.

RANCHI OTTO