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Turbinia

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Viewing 15 posts - 496 through 510 (of 879 total)
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  • in reply to: China sub secretly stalked U.S. fleet #2078709
    Turbinia
    Participant

    This sort of thing goes on all of the time, some countries like to gloat at getting one over, others like to keep it to themselves, and sometimes it is the other country having the real laugh by letting the things happen in the first place. A complicated game.

    in reply to: CVF News #2078710
    Turbinia
    Participant

    IMO there were good reasons for choosing the STOVL J35 and a ski jump configuration, there were also good arguments in favour of catapults. However, if the CVF is going to be pursued in some form of co-operation with France then it’d make sense to risk share and develop common support and upgrade management for things like the AEW system (Hawkeyes I’d hope) and even the naval strike aircraft, and so it does change the argument and make fitting of catapults more attractive.

    in reply to: Merchant shipping #2078718
    Turbinia
    Participant

    Steam winches are good for bigger ships with steam generating plant (boilers) but offshore vessels very rarely have boilers to drive steam powered equipment so are limited to either electric or hydraulic. The advantages of hydraulic are it is very rugged, tough and offers superb fine control quite easily, it is also repairable in the field. Electric systems are compact and get rid of the oil systems, reduce auxilliary plant requirements and now offer control as good as hydraulics, but there are issues with the effects of transients on the main switchboard feeders, generation stability and regenerative power dumping, and a big problem is that if they fail in service they often need specialist service technicians and spares to get them back into action. Maersk were really into electrics. One interesting aspect of the rig winches (not the AHTSS winches) is they tend to use sea water hydrodynamic braking.
    Thrusters use huge amounts of power, on some of the big AHTSS and PSV types you are losing 50%+ of engine power with all the thrusters and deck equipment running. That said to see the manouvering abilities of those boats is awesome, they can do miracles and it always amazed me to see one of them sitting under the rig on DP for days and days with the OOW just looking at a PC screen and the DP computers doing the rest 🙂

    in reply to: Merchant shipping #2079241
    Turbinia
    Participant

    Bollard pull is primarily a function of engine power, it is the pull in tonnes measured at the stern. Winch power is a controversial subject, Bratvag will tell you they’ll sell you a 200T winch with a drum that can hold 5000m of 77mm cable (that is just off the top of my head, not an actual figure BTW, I’m just giving an example) but they are not as quick to tell you that the 200T pull is measured on the first cable layer, as you spool on the cable the pull drops heavily and if the drum has 5000m spooled on it you’ll be lucky to get half of that. Winch power is not the same as bollard pull, although to utilise a high pulling power winch requires a high bollard pull, the winch power is the capability of the winch whereas bollard pull relates to the power of the actual vessel. A big complication is that when anchor handling the vessel will be using tunnel and/or azimuth thrusters and powering it’s winches, spooling gear etc., which draws an awful lot of electrical power which on this type of vessel tends to come from shaft generators, and this obviously drops the bollard pull down heavily. The bollard pull is worked out in a static test, although I’ve never witnessed one so I can’t tell you anything about that, sorry. Some of the winches in large AHTSS now are huge and more and more of them seem to be going electric rather than hydraulic thanks to the ever dropping prices and increased reliability of inverter drives and load banks for control, although Bratvag still insist hydraulic is best.

    in reply to: Merchant shipping #2079393
    Turbinia
    Participant

    Anybody interested in size and lots of big ships together should try and visit Ras Tanura, one of the main Saudi oil export terminals someday, it’s very impressive.

    in reply to: Merchant shipping #2079394
    Turbinia
    Participant

    Seeing ships scrapped is always a sad sight, but part of the eternal cycle of birth, death and renewal that drives industry forward.
    In commercial shipping, there does seem to be a lot of “bigger is best” thinking even if sometimes it is not strictly true. Not just in container carriers, but if you look at AHTSS types the engine powers are now huge with bollard pulls that are frightening, yet often the much smaller but more economical types get equal or even higher day rates.

    in reply to: The best SSK till date? #2079397
    Turbinia
    Participant

    Well, I suppose Bofors is the only company in the world that have been suspected for bribes (they were never found guilty AFAIK). But despite that scandal, India still wants to buy the new Bofors howitzer – the Archer. Why? Cause it´s the best solution for them…

    (BTW, Australia is also considering Archer. But they will probably rename it to Doobidoo or something and members here will think its a true australian product. I don´t care. As long as australia gets the best equipment and the money goes to sweden)

    International arms sales are a sewer and full of kick backs and bribes, however I don’t see the British, American, French, German etc. members making some claim to sit on a moral high horse on the issue. Sweden plays the arms export game like other countries and uses the same tricks and incentives to sweeten customers. If you are going to try and claim that Sweden exists on a higher moral plain then don’t whinge when you get called on it.
    And unfortunately for Sweden, as others here have pointed out, more and more of the profits of Swedish arms sales are going elsewhere, to Germany and the UK to name just two countries that have bought into Swdedish industry in a major way.

    in reply to: The best SSK till date? #2079577
    Turbinia
    Participant

    Would those be the strict arms export controls that prevented Bofors getting involved in that mega fraud scandal for bribing India to get artillery orders? Wait a minute, that’s not right is it……. :dev2:

    in reply to: Merchant shipping #2079579
    Turbinia
    Participant

    The Jahre Viking (or whatever her current name is 🙂 )and the big Prairal/Battilus/Piere Guillaumat trio were only single hull.

    in reply to: The best SSK till date? #2080102
    Turbinia
    Participant

    There is also the point, that Francois has mentioned on the Gotland thread, that since Kockums is now German owned then Sweden is on weak ground on this one, and with the Swedish navy downsizing their submarine fleet and most of the export business for European companies going to Germany and France then Sweden is in no position to laugh at Australia for not having a long term sustainable submarine design/manufacture capability. And indeed, the vast majority of Swedes wouldn’t do that anyway as they have more class and better manners than that.

    Turbinia
    Participant

    Not to mention the post cold war Russias idea of storage- tie it up somewhere and let it rust. 😮

    Sounds like the way Britain does it, at least with diesel-electric submarines….

    in reply to: Aircaft carrier with UCAV #2080376
    Turbinia
    Participant

    That is something that makes me wonder, there seems to be an assumption that UCAV’s will be small and/or cheap, but to be militarily effective and replace manned offensive aircraft they will need to be quite large and heavy and anything but cheap. To me it seems the advantage is losing the pilot, removing inhibitions on mission profile due to pilot survivability concerns, and possibly expanding flight envelope since there will be no pilot, I really don’t expect much reduction in size and I’d be surprised if they’re any cheaper at all.

    in reply to: Merchant shipping #2080380
    Turbinia
    Participant

    The fundamental problem is that the only orders UK yards can realistically compete for these days are UK government orders, and with the downsizing of the Royal Navy and it’s knock on effect on the RFA, and the very limited shipping program for other UK government agencies (NERC, BAS, fisheries protection, Customs and Excise etc.) there just isn’t that much work to support BAE, VT and Swan Hunter, and the government has already decided that voters on the Clyde are more important than voters on the Tyne or anywhere else when it comes to shipping, so c’est la vie. Swan Hunter really ended when BAE got the order for HMS Ocean.

    in reply to: The best SSK till date? #2080405
    Turbinia
    Participant

    Ikara?

    Australia does actually have a thriving ship design business and shipbuilding specialising in high speed craft, and one of the two USN LCS contenders owes a lot to Australian technology.

    Turbinia
    Participant

    Maybe because Sweden had a modern surplus boat they wanted to offload onto somebody else and the other navies with modern SSK’s want to retain them for their own use? :confused:

Viewing 15 posts - 496 through 510 (of 879 total)