CPV Replacement

[spider]

I've been a follower of the debate on here around the re-building programme for the Irish Navy...the need for an EPV...the fact that CPV's are probably needed to police the inshore fisheries around the various bays and inlets etc etc.

Then the recent refugee crisis in the Mediterranean...and the decision to deploy the UK Border Agency Cutters got me looking at the Damon Stan vessels.

Operated by services as diverse as the UK Border Agency...the United States Coastguard...the Mexican Navy...are these or a version of them a potential replacement for LE Orla and LE Caira?

They seem to be reasonably priced ($5.37 million per US Ship 4.94 million Euros) ...could these be an option to allow funds to be diverted into the much required larger patrol vessel / EPV?

Are they capable of doing the job...I've attached a couple of youtube videos showing their handling in moderate seas...

https://www.youtube.com/watch?v=xftrxGL8S48

https://www.youtube.com/watch?v=ruZGPJoxOUA

https://www.youtube.com/watch?v=-9uj028MH5E

The US Coastguard version is armed with a 25mm Bushmaster canon...but only has a 5 day endurance as opposed to the unarmed UK version of 12 - 14 days.

http://www.oig.dhs.gov/assets/Mgmt/2...2-68_Aug12.pdf

http://en.wikipedia.org/wiki/UKBF_42m_Customs_Cutter

I have photos somewhere of one of the UKBA Cutters alongside Belfast docks...I'll try to find them.

I'll leave any discussion in the hands of those who know what they are talking about

[ancientmariner]

CPV replacement would require something capable of patrolling all waters of the Irish Coast while operating independently. They would need a basic range at 12 knots of about 2250 n.m or 7 to 8 days continuous steaming. They would accommodate up to 30/35 crew and trainees. Carry suitable inspection/interdiction craft. Be capable of speeds up to 25knots. Armament suggested 30mm Bushmaster with FCS and 2x20mm. Full navigation and detection suite for surface and air. Length probably 60 metres. Adaptable for containerized systems as required.

[na grohmiti]

Ocean Going tug or something in that ilk seems the ideal option to me.

They have excellent manoeuvrability in confined waters, and many are already in service in other navies and coast guards, mostly those with an emerging Oil industry.

[spider]

So is there anything 'off the shelf'...or are we talking a custom built design.

[na grohmiti]

There are off the shelf designs. Damen do a larger type, however many of the offshore support ships would be suitable. All are fitted with daughter craft as standard, all are stable in horrible seas, though the Damen are 90m, but there are similar smaller types in use. Like KV Nornen for example.


Or a similar type SHV Olav Tryggvason

[spider]

Looks good...two (or more) birds...one stone etc

Therefore easier to justify to the bean counters (hopefully)

[DeV]

16 kts max speed
12% bigger draught than the Peacocks
20 tonne bollard pull

Not suitable
A PV needs 20 kts min, if we want a CPV then a similar draught to the Peacocks and we would be looking at a 500 tonne bollard pull to be anyway useful (1000 tonne is what we need)

[na grohmiti]

Why say you so?

[DeV]

Which bit?

20 kts? Deirdre had a speed of 18 kts and was the slowest vessel

Draught - didn't you say on another thread that the OPVs had too deep a draught to put into many Irish harbours?

All the reports that have been commissioned say 150-200 tonne bollard tow required for a ETV, something with 20 tonnes is smaller than a harbour tug

[ancientmariner]

Which bit?

20 kts? Deirdre had a speed of 18 kts and was the slowest vessel

Draught - didn't you say on another thread that the OPVs had too deep a draught to put into many Irish harbours?

All the reports that have been commissioned say 1000+ bollard tow required for a ETV, something with 20 tonnes is smaller than a harbour tug

Just to clear the air Bollard pull is the pulling strength one vessel has in Tonnes in order to overcome the inertia of a floating or grounded structure. It is roughly calculated on the Formula BHP X 0.9 X1.25 divided by 100 for a vessel with freewhelling CPP's ie NO Kort nozzles. Therefore a 5000BHP ship can only have a bollard pull of 56 Tonnes. Most ocean tugs would be bollard pull under 100tonnes. The Celtic Isle that towed a 3500tonne in an Atlantic gale last year had a bollard pull of 56tonne and a winch brake capacity of 100tonnes. To achieve 500Tonne bollard pull you will have to build a ship that at the moment doesn't exist.
The theory is once you move a ship, overcoming it's inertia, moderate power is needed otherwise you bust the weakest link ie the tow ropes. An 8inch circumference tow rope has a breaking strain of 64 tonnes and a Safe Working load of 32Tonnes. In my opinion a ship with a bollard pull of 50/60 Tonnes is more than adequate.

[hptmurphy]

CPV replacement would require something capable of patrolling all waters of the Irish Coast while operating independently. They would need a basic range at 12 knots of about 2250 n.m or 7 to 8 days continuous steaming. They would accommodate up to 30/35 crew and trainees. Carry suitable inspection/interdiction craft. Be capable of speeds up to 25knots. Armament suggested 30mm Bushmaster with FCS and 2x20mm. Full navigation and detection suite for surface and air. Length probably 60 metres. Adaptable for containerized systems as required.

Hang on... sounds like a Ton Class minesweeper witha bit of pep in the speed stakes!

[ancientmariner]

Hang on... sounds like a Ton Class minesweeper witha bit of pep in the speed stakes!

Try a Fassmer 60m CPV. They are a German group. I think Chile has an 80m version. The other short term solution are the RN River class which will be surplus next year. They were mostlly built post 2003 and could carry on to 2033/34. Fit them out , weapon wise ,the same as the Falklands ship HMS Clyde.

[DeV]

Just to clear the air Bollard pull is the pulling strength one vessel has in Tonnes in order to overcome the inertia of a floating or grounded structure. It is roughly calculated on the Formula BHP X 0.9 X1.25 divided by 100 for a vessel with freewhelling CPP's ie NO Kort nozzles. Therefore a 5000BHP ship can only have a bollard pull of 56 Tonnes. Most ocean tugs would be bollard pull under 100tonnes. The Celtic Isle that towed a 3500tonne in an Atlantic gale last year had a bollard pull of 56tonne and a winch brake capacity of 100tonnes. To achieve 500Tonne bollard pull you will have to build a ship that at the moment doesn't exist.
The theory is once you move a ship, overcoming it's inertia, moderate power is needed otherwise you bust the weakest link ie the tow ropes. An 8inch circumference tow rope has a breaking strain of 64 tonnes and a Safe Working load of 32Tonnes. In my opinion a ship with a bollard pull of 50/60 Tonnes is more than adequate.

Yes, slight typo 150-200 bollard pull

[Sparky42]

Try a Fassmer 60m CPV. They are a German group. I think Chile has an 80m version. The other short term solution are the RN River class which will be surplus next year. They were mostlly built post 2003 and could carry on to 2033/34. Fit them out , weapon wise ,the same as the Falklands ship HMS Clyde.

Except there is still zero confirmation that the RN is going to sell them, nor will they be available next year as the Batch 2's are being built to cover the gap in orders due tothe 26's issues. At best it will be only after the next Defence review post election that anyone will know what will happen to them, and given the lack of numbers in the RN cupboard I don't see the Admirals being willing to give them up, even if they are getting 3 new ones they didn't want.

[ancientmariner]

You would achieve a bollard pull of 150 Tonnes with a suitable ship of 13,500 BHP using CPP's. The same ship with fixed pitch would achieve 133 Tonne pull. Some of our ships were fitted with Tortion meters on their shafts so that you wouldn't overload the Main Engines while towing. The Icelandic THOR has two 10,500 BHP engines and in excess of 150Tonne bollard pull. The four Brits ETV's average 165 Tonne pull.