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Ship Life... watch

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    I wouldn't want to put one of those piston rings on!
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    We have a special tool to do it, I tried it, but the ring flew out the tool, went straight up, smashed the light above our heads and then gouged itself in the air vent.

    I didn't try again.
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    (Original post by gbduo)
    The engines drive generators, so torque I don't know, but they run at 514rpm, they have around 20,000hp each which generates about 14.5MW of electrical power. There are 4 engines. So 80,000bhp in total, 48MW.

    14,500,000 Watts in other words. That is a a lot of light bulbs...!

    The motors which drive the ship, have about 1400KNm of torque, but can go up to 1600KNm in an emergency. Each motor is about 27,000bhp each. Max revs are 140rpm.
    And how do you calculate hp Graham? :p:
    Cool pics though! I'm thinking about going into ME but a slightly different route..
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    (Original post by CurlyBen)
    And how do you calculate hp Graham? :p:
    Cool pics though! I'm thinking about going into ME but a slightly different route..
    Meh, they were from memory, so could well be wrong, I will look it up in the manual, do you think they are wrong?

    What route would that be? RN?
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    (Original post by gbduo)
    We have a special tool to do it, I tried it, but the ring flew out the tool, went straight up, smashed the light above our heads and then gouged itself in the air vent.

    I didn't try again.
    Strangely, that's near enough what I imagined would happen haha!
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    (Original post by gbduo)
    The engines drive generators, so torque I don't know, but they run at 514rpm, they have around 20,000hp each which generates about 14.5MW of electrical power. There are 4 engines. So 80,000bhp in total, 48MW.

    14,500,000 Watts in other words. That is a a lot of light bulbs...!

    The motors which drive the ship, have about 1400KNm of torque, but can go up to 1600KNm in an emergency. Each motor is about 27,000bhp each. Max revs are 140rpm.
    holy hell, that's a lotta juice! is that purely to run the ships ancileries + systems?

    you'll have JC trying to jimmy one into his hotrod if you're not careful :laugh:
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    (Original post by CurlyBen)
    And how do you calculate hp Graham? :p:
    Cool pics though! I'm thinking about going into ME but a slightly different route..
    Just looked it up, total power from the engines is 58,800KW, 1KW = 1.34bhp

    So 79,909bhp? Not bad from memory!
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    (Original post by Samalama)
    Strangely, that's near enough what I imagined would happened haha!
    Yeh and they cost £1000 each, there are 4 of them!
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    (Original post by jaw)
    holy hell, that's a lotta juice! is that purely to run the ships ancileries + systems?

    you'll have JC trying to jimmy one into his hotrod if you're not careful :laugh:
    No that electrical power will run the whole ship, but 40MW of the 48MW is used to drive the ship through the water, so over 80% just in propulsion...

    The next big consumer is Air Conditioning (3x1.5MW motors) and Bow Thrusters (4x 2MW motors) and then all passenger services. However, it is very rare that you will need all of those running at the same time with propulsion on max as well. Obviously you don't use your bow thrusters when you are steaming at 24knots! Only in port.

    Most of the time, you only need 28MW coming into port, maximum, normally only 14MW.

    Oh and those motors are the size of a average house and weigh the best part of 200 tonnes.
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    (Original post by gbduo)
    Meh, they were from memory, so could well be wrong, I will look it up in the manual, do you think they are wrong?

    What route would that be? RN?
    No, it's not that, but you said you didn't know the torque - power = torque x speed, so torque = power/speed! To produce 20,000hp (about 14,900kW) at 514rpm (about 53 radians/s) you need to produce about 280kNm of torque. That'll shift a bit.
    And yeah, thinking about RN at the moment
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    (Original post by CurlyBen)
    No, it's not that, but you said you didn't know the torque - power = torque x speed, so torque = power/speed! To produce 20,000hp (about 14,900kW) at 514rpm (about 53 radians/s) you need to produce about 280kNm of torque. That'll shift a bit.
    And yeah, thinking about RN at the moment
    Oh!!! I see, duh! I obviously just could not be arsed, lol!

    280KNm will shift a bit, bearing in mind the beasty Audi V12 TDi only has a measly 1KNm!

    Haha!

    RN is a good career, lots of guys onboard came from the RN.
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    Can you imagine what you would need to place on the end of that engine to stall it :p:
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    (Original post by CurlyBen)
    Can you imagine what you would need to place on the end of that engine to stall it :p:
    An awful lot of electrical load! Some serious emf!

    You can stall the biggest engines though simply by getting something caught around the propellor, hitting the sea bed or getting a rope caught (big one) can cause the biggest engines to stall. They rev proper slowly the direct drive engines so it is not hard to stall them!

    Max revs on the biggest engines is like 110rpm.
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    Are you merchant navy guys actually getting any decent anti-piracy training or protection yet???
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    (Original post by gbduo)
    An awful lot of electrical load! Some serious emf!

    You can stall the biggest engines though simply by getting something caught around the propellor, hitting the sea bed or getting a rope caught (big one) can cause the biggest engines to stall. They rev proper slowly the direct drive engines so it is not hard to stall them!

    Max revs on the biggest engines is like 110rpm.
    They might be slow, but they've still got a massive amount of inertia! Do you often get problems with prop wraps etc? Do you have to send a diver over? I always used to wrap props on RIBs when moving racing marks and being too lazy to lift the whole thing, I just used to drop it into reverse at idle, normally did the job
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    (Original post by CurlyBen)
    They might be slow, but they've still got a massive amount of inertia! Do you often get problems with prop wraps etc? Do you have to send a diver over? I always used to wrap props on RIBs when moving racing marks and being too lazy to lift the whole thing, I just used to drop it into reverse at idle, normally did the job
    Yeh and that is a major problem, the inertia, the engine stalls but because the engine is so large, different components grind to a halt at different rates. Queue twisted crankshaft, broken con rods and worn out crankshaft journal bearings.

    An engine stalling is a big deal and can indeed lead to the complete write off of an engine and is a all too common occurrence with poorly crewed ships in poor Ports. Africa and the far east are where most accidents happen.

    Put it this way, untangling the rope is the least of your worries!
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    (Original post by gbduo)
    Yeh and that is a major problem, the inertia, the engine stalls but because the engine is so large, different components grind to a halt at different rates. Queue twisted crankshaft, broken con rods and worn out crankshaft journal bearings.

    An engine stalling is a big deal and can indeed lead to the complete write off of an engine and is a all too common occurrence with poorly crewed ships in poor Ports. Africa and the far east are where most accidents happen.

    Put it this way, untangling the rope is the least of your worries!
    Ouch, sounds painful! We wrapped the prop on a yacht a while back, a nice aramid kite sheet. Dragged up into the saildrive leg bearings, so the diver couldn't free it. Went and raced the last of the weekend (in anything up to about 35 knots) before taking it back up the Hamble and mooring up alongside a Farr 40 whilst under sail. The most interesting bit about that was the the Farr 40 doesn't have any cleats or fairleads for mooring!
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    (Original post by CurlyBen)
    Ouch, sounds painful! We wrapped the prop on a yacht a while back, a nice aramid kite sheet. Dragged up into the saildrive leg bearings, so the diver couldn't free it. Went and raced the last of the weekend (in anything up to about 35 knots) before taking it back up the Hamble and mooring up alongside a Farr 40 whilst under sail. The most interesting bit about that was the the Farr 40 doesn't have any cleats or fairleads for mooring!
    Nice bit of sailing there! Mooring up a yacht under sail, that is pretty impressive especially in the close confines of the Hamble!

    There was a yacht which had run aground on the hamble mouth last week. Warsash sits on the mouth of the Hamble, so us engineers were all laughing at it! The Deckies (navigation) were all cringing! Lol!

    But yeh, wrapping props is never good, but tbf, running aground is far worse when the engine is going full whack. That really is a right off.

    Go to:-

    www.marinediesels.co.uk and then horror stories under operation...
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    It was.. interesting.. particularly with a F6 blowing onto the Farr, and not a lot of space cos of the hammerhead. We had to tack round with about two boat lengths to spare, which kept everyone nicely concentrated! Yeah I know where Warsash is, I sail past most weeks, past your nice collection of lifeboats!
    I think I've seen that marine diesels site before actually, though some of the links just seem to go back to the homepage. Certainly makes you think about trying to bodge a job!
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    Haha, the big orange monstrosities!

    I probably directed you there before, seems to be working fine now, my tutor (the webmaster) did a lot of work on it over the summer.

    Yep! There are some jobs you can bodge, some you really cannot!

    Bloody hell, some serious seamanship with that yacht in a F6, I feel for you! Must have been a very interesting, but probably very rewarding experience! Don't get to do that often!
 
 
 
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