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Arctic/Offshore Patrol Ship AOPS

MTShaw

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Back to Halifax for HDW after only a few days at sea from her last repair. Not exactly a huge confidence booster for such a relatively new vessel on the inaugural two ship Arctic deployment of the class.
To true. the first of any class of warship tends to suck I’m actually proud of our naval engineers for finding these problems in that they find problems down here instead in the Arctic.
 

KevinB

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Know not if that is important.


EDIT: didn't even notice that stuff had been posted already.
Still had 3/4 of the DG’s left.
One figures the damage to the 1 had to be really significant to divert - or concern it may cascade.
 

Jarnhamar

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To true. the first of any class of warship tends to suck I’m actually proud of our naval engineers for finding these problems in that they find problems down here instead in the Arctic.

COs coin for doing a vehicle DI.
 

Oldgateboatdriver

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Still had 3/4 of the DG’s left.
One figures the damage to the 1 had to be really significant to divert - or concern it may cascade.

Not necessarily.

She was going to the Arctic, in situations where she was expected to go in and break fairly thick ice. Missing one quarter of your power (not to be confused with speed) is significant.
 

Stoker

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Still had 3/4 of the DG’s left.
One figures the damage to the 1 had to be really significant to divert - or concern it may cascade.
These DAs are quite large and certain parts are not typicially carried. There are many factors to consider when making a decision to return. It could be as simple as how hard it would be to get technical staff and parts in for repairs in the Arctic which is not easy. It also could be what is the min safe to sea state the ship could be in before it would have to go along side. We have a document called the material baseline standard that dictates what is the min technical state we need to be at before going to sea or remaining at sea safely.
That being said the failure wasn't catastrophic and no danger of causing any other issues to the other DGs.
 

Good2Golf

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I’m tracking correctly that these DGs are propulsion, not smaller ones for hotel power, right? Like the CCG R-Class?
 

Oldgateboatdriver

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You are correct that they are "primarily" for propulsion (i.e. to provide the power to the electric motors). But on an "all-electric" vessel, any DG can be used to provide part or all of the hotel services if you want/had to.

Don't know what you refer to about the CCG R-boats. They didn't have electrical propulsion, they had diesel driven twin screws.

You may be thinking of the CCG icebreakers. Icebreakers are generally electric motor driven to reduce potential ice damage to the screws and engines. Think snowblower: If you have a gas one it will chomp through ice and snow even if it damages the turning blades, until it stalls the engine. An electric one will stop moving if too much ice and snow is encountered, but back off a bit to reduce the amount and the motor will start turning again right away.

Same concept for icebreakers: If the screws were diesel driven through gearbox, any large chunk of hard ice that would drift into them would cause either damage to the screw, the gearbox and ultimately even stall the diesel engine. Electrical motor just takes the hit and either slows down or stops while the ice chunk blocks the screw and start to rotate as soon as it clears (like the old small fans of our
youth: stick your finger in and it stops, restarting as soon as you remove it).
 

Good2Golf

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Don't know what you refer to about the CCG R-boats. They didn't have electrical propulsion, they had diesel driven twin screws.
I thought they had ALCOs driving generators, powering main electric motors driving the shafts? Isn’t that like the AOPS setup?
 

Stoker

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I’m tracking correctly that these DGs are propulsion, not smaller ones for hotel power, right? Like the CCG R-Class?
All 4 DGs provide propulsion. As you need more power you bring on another DG. At sea you always have a min one DG online. Each DG has a 450V Alternator that provides hotel load. As back up you have one emergency DG.
When HDW left they had 3 DGs with the intention of picking up parts in a port and repairing the 4th. When the 3rd failed they only had 2 DGs, didn't meet MBS and they decided to return to Halifax.
 

Oldgateboatdriver

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Well, I drove Rally when she was in the reserve fleet, and my recolection is twin diesel driving screws. Maybe Colin can correct me if I am wrong.

Maybe you have a different R-class in mind. These were dinky toy little 95 footers used as SAR cutters with pretty small engine compartment. Diesel electric drives would have been pretty complex things to put in such small vessels. Besides, I distinctly remember that we had to "click" the throttles in at the lowest setting and wait a second or two for the screws to engage before we could slowly ramp up the RPMs, which to me is indicative of a fixed pitch screws on diesel driven shafts - not electric motors.

Perhaps it is the MCDVs you have in mind. They are diesel electric ships set up the same way as the AOPS (or rather, the AOPS are set up like the MCDVs because "chicken and egg").
 

Good2Golf

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Well, I drove Rally when she was in the reserve fleet, and my recolection is twin diesel driving screws. Maybe Colin can correct me if I am wrong.

Maybe you have a different R-class in mind. These were dinky toy little 95 footers used as SAR cutters with pretty small engine compartment. Diesel electric drives would have been pretty complex things to put in such small vessels. Besides, I distinctly remember that we had to "click" the throttles in at the lowest setting and wait a second or two for the screws to engage before we could slowly ramp up the RPMs, which to me is indicative of a fixed pitch screws on diesel driven shafts - not electric motors.

Perhaps it is the MCDVs you have in mind. They are diesel electric ships set up the same way as the AOPS (or rather, the AOPS are set up like the MCDVs because "chicken and egg").
Sorry OGBD, I meant Raddison class. CCG site interchangeably uses ‘Medium Icebreaker’ and Raddison/R Class.
 

Oldgateboatdriver

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OK. That makes sense. Yes the Radisson/Amundsen/Des Grosseilers are set up exactly like the AOPS (or, again, the reverse). First time I hear they are referred to as the R class. Coast guard tends to refer to them as the Type 1200 ice breakers.
 

Good2Golf

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I remember Colin referring to 1100s, but haven’t heard 1200s before. Funny that the CCG site doesn’t use the term Type 1200 for the Raddison / Imrpoved-Raddison types…that I could find.

 

Good2Golf

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Ah, there it is, the Formerly Known As… 👍🏼

…although in fairness to me I was trying to us CCG site, vice Wikipedia. 😉

The CCG site is a bit of a jumble (though lot as bad at DND’s.
 
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