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  • DeV
    replied
    Originally posted by spider View Post
    How about the bigger brother of the 4207...


    [ATTACH]7963[/ATTACH]
    Draught?

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  • ibenji
    replied
    Originally posted by spider View Post
    How about the bigger brother of the 4207...


    [ATTACH]7963[/ATTACH]
    I am all for the NS getting new ships but these damen ships are fairly ugly. Not as sleek as the current class of ship being delivered. Surely the new drones can venture in where the P60's can't. Bigger is better

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  • spider
    replied
    How about the bigger brother of the 4207...


    Damen_Stan_Patrol_6011_Sea_Axe.pdf

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  • Sluggie
    replied
    I believe that a former FOCNS used to refer to the CPVs as "the motorbikes"

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  • DeV
    replied
    Looking at naval technology to be honest I don't think there is anything out there that fits the bill. In the main everything available is either OPV sized, fast attack craft, designed for much more sheltered waters, too small etc. The best all weather option is something like the Tamar or Safehaven but they are not really designed to be at sea longer than 24 hours.

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  • Marius
    replied
    Any replacement for CPVs -when the time comes- must represent an advance on current caps. CPVs are twin screw, twin engine room, 76mm armed, FCS- and-IR-equipped fighting ships with multiple system redundancies including comms, conning, propulsion, generation. They mix sprint capability with slow single engine running or (in calm weather) loiter. Their draft gives them full coastal access but their seakeeping means they can work offshore. No need to list their disadvantages...we are all familiar with them too. But it would be a disaster to willingly replace these vessels with - as mentioned above- an 'ocean going tug' with some sub-calibre infantry support weapon as a main armament. Replace like with like, improve upon it in the process and -yes- we will take that ocean going tug as well, thank you very much.

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  • hptmurphy
    replied
    Fassmer 60m CPV
    Outsorce the builds to Poland and we'll have them in 12 months. Nice looking vessel.

    The other short term solution are the RN River class which will be surplus next year
    Not as a suitable replacement for the CPVs if you want to downsize as they are closer in capabilty to Roisin and Niamh

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  • DeV
    replied
    Thor however has a draught of 5.8 metres

    Samuel Beckett is 3.8 metres
    Ciara is 2.72 metres


    A CPV could be a dive tender as well but not an ETV
    Last edited by DeV; 27 April 2015, 15:44.

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  • ancientmariner
    replied
    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.

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  • Sparky42
    replied
    Originally posted by ancientmariner View Post
    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.

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  • DeV
    replied
    Originally posted by ancientmariner View Post
    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

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  • ancientmariner
    replied
    Originally posted by hptmurphy View Post
    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.

    Leave a comment:


  • hptmurphy
    replied
    Originally posted by ancientmariner View Post
    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!

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  • ancientmariner
    replied
    Originally posted by DeV View Post
    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.

    Leave a comment:


  • DeV
    replied
    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
    Last edited by DeV; 27 April 2015, 13:39.

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