Eternal Father (or, more to the point, what's going on with the water)

NSP

LE

Found link above. Notwitstanding the "sailor's lament" attendant I am more interested in the war canoe. In several shots I'm sure I can see water pouring from a thruster tunnel in the bow.

Thus, my question is: on an obvious ASW platform (as indicated by the under-bow bulge of the forward sonar array) why would you have a thruster tunnel? Apart from the drag when doing fleet carrier speed escort-type stuff there's the obvious noise profile attendant to having a hole on each side of the bow, regardless of speed. What gives (and I ask as someone who works on dynamically-positioned vessels, that have thrusters coming out of their arses sterns)?

Surely having to be tugboat-assisted alongside is better than an elevated noise profile from flow across the tunnel ports when steaming?

Perhaps one easily put to bed by @Ravers @supermatelot @Jimmy_Green et al...?
 
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I think you must be mistaken. To the best of my knowledge warships don't have bow or stern thrusters, although I couldn't say for sure for capital ships like aircraft carriers. If there were thrusters there should be an indication painted on the hull above the waterline above the position of any thrusters, which can clearly be seen painted in white in the image below. It's not something I've ever seen in a warship and I've been under enough of them when in dry dock.



What you see in the video is not replicated as in the above picture.

There are a lot of inlets and outlets in the ship's hull below the waterline for such things as fire main, RO plants and bilge pumps etc. If these inlets/outlets are full of oggin it would make sense for the water to drain when the hull clears the sea and I suspect that's what you are seeing in the video.

On survey vessels and vessels such as you work on dynamic positioning may be essential but not for a warship. A warship does need good stabilisers though.

Noise for a warship coming alongside is irrelevant. Noise is only really an issue when prosecuting sludgemarines and I doubt that they're going to be attacking a ship as it's about to tie up alongside. Even when making way, at speed, there would be so much radiated and cavitation noise that any additional flow noise from thrusters would be drowned out as to again make it irrelevant.
 
I think you must be mistaken. To the best of my knowledge warships don't have bow or stern thrusters, although I couldn't say for sure for capital ships like aircraft carriers. If there were thrusters there should be an indication painted on the hull above the waterline above the position of any thrusters, which can clearly be seen painted in white in the image below. It's not something I've ever seen in a warship and I've been under enough of them when in dry dock.



What you see in the video is not replicated as in the above picture.

There are a lot of inlets and outlets in the ship's hull below the waterline for such things as fire main, RO plants and bilge pumps etc. If these inlets/outlets are full of oggin it would make sense for the water to drain when the hull clears the sea and I suspect that's what you are seeing in the video.

On survey vessels and vessels such as you work on dynamic positioning may be essential but not for a warship. A warship does need good stabilisers though.

Noise for a warship coming alongside is irrelevant. Noise is only really an issue when prosecuting sludgemarines and I doubt that they're going to be attacking a ship as it's about to tie up alongside. Even when making way, at speed, there would be so much radiated and cavitation noise that any additional flow noise from thrusters would be drowned out as to again make it irrelevant.
Albion and Bulwark have bow thrusters. Enterprise also, which backs up your point regarding Survey Vessels.
 
Cavitation and other noise from the hull can also be mitigated by use of a “system” that Was, dunno about nowadays though...a bit secret.
 
Cavitation and other noise from the hull can also be mitigated by use of a “system” that Was, dunno about nowadays though...a bit secret.
Ah, the M.O.N.G. Coating. Basically gorilla glue mongtards around the hull and have them Mllaaaaar constantly. Distracts from the cavitation and such.
 
Ah, the M.O.N.G. Coating. Basically gorilla glue mongtards around the hull and have them Mllaaaaar constantly. Distracts from the cavitation and such.
Hehe...a similar principle!
 
Just seen it’s open source now anyway.

Agouti and masker.
 

Seadog

ADC

Found link above. Notwitstanding the "sailor's lament" attendant I am more interested in the war canoe. In several shots I'm sure I can see water pouring from a thruster tunnel in the bow.

Thus, my question is: on an obvious ASW platform (as indicated by the under-bow bulge of the forward sonar array) why would you have a thruster tunnel? Apart from the drag when doing fleet carrier speed escort-type stuff there's the obvious noise profile attendant to having a hole on each side of the bow, regardless of speed. What gives (and I ask as someone who works on dynamically-positioned vessels, that have thrusters coming out of their arses sterns)?

Surely having to be tugboat-assisted alongside is better than an elevated noise profile from flow across the tunnel ports when steaming?

Perhaps one easily put to bed by @Ravers @supermatelot @Jimmy_Green et al...?
the like is for the film; now that’s what I call ‘roughers’.

Whatever the OP is seeing, it’s unlikely to be a thruster.
 

load_fin

War Hero
Reminds me of "The Cruel Sea".

Something like "There's no better place to hide than the North Atlantic in winter"

M'learned matelot friends - what sea state is that?
 
It's always important to differentiate between significant wave height, swell, and sea state.

In that video 3-4m, 2-3m and sea state 7. Storm Ciara was similar last week.

(As pertinently, the CO of that ship obviously doesn't value his bow dome, gun or ship's company. He needs to reduce speed by 5-10kts...)

ETA - I've been in the south west monsoon with a 10+m swell, negligible sig wave and sea state 1.
 

load_fin

War Hero
It's always important to differentiate between significant wave height, swell, and sea state.

In that video 3-4m, 2-3m and sea state 7. Storm Ciara was similar last week.

(As pertinently, the CO of that ship obviously doesn't value his bow dome, gun or ship's company. He needs to reduce speed by 5-10kts...)

ETA - I've been in the south west monsoon with a 10+m swell, negligible sig wave and sea state 1.
I thought the speed was excessive, but then the ship crests a wave, buries the bows in the next one and almost stops.
Would less speed have been better, or more speed to get up the next one?
 
It really does depend - until you're in it you can't tell.
 

Yokel

LE
My late Grandfather was in an Arctic Convoy when a wave ripped off the flight deck of the escort carrier - causing concern as it meant no fighter cover or ASW patrols. Ironically the rougher the sea the hard life was for the U boats.

I once saw a potential regular Warfare Officer looking looking green aboard a CVS in the North Sea. It was a bit rough though, and we steamed up to the Scottish East coast to carry on with fixed wing work ups.
 

Yokel

LE
It really does depend - until you're in it you can't tell.
Is that one of those elements of practical shiphandling that you really need to pick up from experience as OOW and cannot really be taught in a simulator or classroom?

One of my University lecturers used to like saying "the theory and calculations just get you into the same room as the dartboard".
 

merchantman

War Hero
Reminds me of "The Cruel Sea".

Something like "There's no better place to hide than the North Atlantic in winter"

M'learned matelot friends - what sea state is that?
I would guestimate that as beaufort force 9, very rough sea. We tended not to use the numbering system much for sea conditions unless we were a "selected ship" and reporting back to the met office every 6 hours. I agree with AtG that the skipper should think about reducing speed a touch
 
Reminds me of "The Cruel Sea".

Something like "There's no better place to hide than the North Atlantic in winter"

M'learned matelot friends - what sea state is that?
That's what's known in the trade as 'a bit lumpy'. There's still a way to go before it becomes 'Harry roughers'.
 

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