AAW Frigate (not a kitbash this time!)

Shipright wrote:

heuhen wrote:

Even the Americans have the same problem, on a Burk it's nor an problem because the hull of an Burke is so big, but when you get smaller as an frigate, that have much bigger motion in the sea, and also tend to be driven much harder in bad weather than a destroyer. so where ever you are in the world you will every year come over weather bad enough to rip of the life raft on a frigate sized hull. An Destroyer is Big thus some of the problem is gone. if you take an look at an OHP class some are an frigate, then you will notice that the Americans have mounted there life raft on deck due to the risk as I mention earlier.

Yes, if your ship requires them to be lower and farther forward then thats what you do or put them on deck, but this is not the case here. They are over four decks above the waterline. In fact if you are worried about waves ripping off lift rafts at that level you need to worry about waves sweeping people off the bridge wings.

I get your experiance is with extreme North Sea weather but that is and always will be a niche enviroment.

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the same to the British Type 23 frigate. frigates from Netherland, Germany. But as soon they get bigger than a frigate, they tend to just hang it over the board.

Compare the position of the life rafts as drawn with that on the Burkes. They are actually higher.

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But there is also and thumb rule: If you have space for it on deck, mount it on deck.
and If you draw an modern frigate like he have her. mount it on deck, the only reason Burk have mounted on the side, is to open up space for special operation, and that they need the space for extra equipment. Specially when you have an ship with 300 men on a ship that is just 40 meter longer, thus you need more deck space for them. on a frigate that have 120-130 men on a hull that is 40 meter shorter have the space, because the crew is smaller.

Yes for steath it is a superior position and Burke has a lot of stuff competing for deck space. I would agree that making space for chaff launchers, boat davits and the like are a major driver of their slung position. That and not spoiling the LOS of SPY.

People, however, are NOT one of those things competing for deck space. Seriously in what situation are you imagining where the entire crew needs to be on deck? Are we expecting to grapple and board the opponenent? Not only that, you can fit all 300 people on just a part of the fight deck or focsle with no problem. We do it all the time for award ceremonies.

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so get those life raft on deck. it's better protected there, it's more accessible, specially when you going to service it from time to time. specially on a ship that will be used every day. In a fleet with a Burk-spam, you can easily have one go into port for just controlling it's life-rafts, and in that period the ship can't be used. while the frigate with his life raft on deck...

1.) You don't "use" these life rafts as in manually handle them. You release the cannisters (or they self release, see below) into the water and then they self inflate. Its a zero maintenance system as far as the crew is concerned thought he mounts like to create running rust like any hull attachement.
2.) You don't service them either. They are in self contained enclosures specifically designed to basically explode out of their shell instantly when triggered or when at a certain depth if sinking with the ship. Because of this there is no way to open them and then repackage them. All similar systems work the same way.
3.) These things can be moved on and off a ship by crane in a matter of hours for all of them. Same with putting them back on. You don't generally have ships using all their life rafts and then returning for a reload for obvious reasons, so this maitenance is no different than any other a ship needs and scheduled alongside other in port maintenance.
4.) Life rafts on deck have the exact same shelf life and maintenance needs of life rafts anywhere else.

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Of the life raft system on Burk works, it give extra cost in production (no need for that), it's reinforced, to handle the weather, it have an sort of wave/spray brake (prevent water on to the raft and salt damaging it's systems), and many other things that just make it all more expensive than needed.

They are literally racks made out of welded I-beam, probably little to no difference in cost to whatever craddle your deck mounted ones use. It is not reinforced (why would dit be?), they have no wave/spray brake and as I have said before salt builds up regardless of direct wave action or not, and there is nothing about them that make them more expensive than something mounted on deck. You obviously have never seen or know anything about these rafts in particular, so why make this stuff up?

I know a lot about life raft's and it's systems. but dunno, I am not going to cluster this topic up with this...

RP1 wrote:

Well, for the British and Dutch, SeaMaster 400 didn't exist when the decision was made. Also it would not work on Type 45. I should probably give some background:

Now that is interesting stuff!

So...would the proposed modified I-Mast 500 with APAR work with the SM range? Regular I-Masts wouldn't be sufficient, but surely the APAR would provide the missing capability?

RP1 wrote:

Literally just move it forward one compartment and you'll eliminate several damage cases that can take out both shafts in one go. Ideally it would be separated by at least one compartment, but that's probably not possible on a ship this size.

Okay...how about this?

[ img ]

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Are you using IFEP- i.e. can the forward GTAs be connected to the propulsion bus? Even if the system is normally run in an isolated mode but can be connected you will have some propulsion.

Yes. The design is intended to have a fully-integrated power system, allowing for some redundancy (and more efficient usage).

Seems not unreasonable. If you lower the SVTT one deck level, you will have a much easier time sharing a torpedo magazine with the helicopter.

erik_t wrote:

Seems not unreasonable. If you lower the SVTT one deck level, you will have a much easier time sharing a torpedo magazine with the helicopter.

That was actually the plan, but I was tired when I made that last picture and I managed to botch it!

Anyway...after taking on board all the suggestions, this is what I've come up with:

[ img ]

Yes, it could be more detailed, but I'd prefer not to add pixels without a clear purpose.

If I were you I would disburse the turbines rather than the drive motors. Having different length shafting adds complexity to your design and will require the inclusion of maintenance intensive thrust bearings on the longer shaft. Not to mention that at the beam of the ship at the shafts a hit to one is probably going to screw up the other one anyway. Perhaps swap your forward generator and aft turbine. Honestly though if you want to go with simplicity and cost savings you can just keep it as you originally had it with drives, turbines and generator in their own engineering space.

Also have you put any thought into countermeasures like chaff or nulka?

Shipright wrote:

There are two reasons why I separated the motors, but not the turbines. Even if the main turbines are knocked out, the ship could still use the auxiliary generators to move, albeit slowly; however, if both engines are knocked out, it won't be going anywhere- no matter how much of the electrical capacity is still available. This was something that had been floating around somewhere at the back of my mind from the start and when RP1 raised the issue, I was convinced. You do raise a good point about the vulnerability of the shafts, though.

The second reason- less valid in design terms but arguably a much greater issue with a drawing- is that dispersing the main turbines requires a major reworking of the layout. In particular, it means squeezing in a second funnel- something I was eager to avoid (although...I've just spotted a way I could achieve that...maybe...hmmm)!

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Also have you put any thought into countermeasures like chaff or nulka?

Chaff launchers would be fitted above the hangar forward of the Millenium Gun and abreast the mast abaft the bridge. But would they be visible above the solid railings? In the drawings I've seen of other similar ships with solid railings, for instance the Nansen, Provincien and Daring, I can't see any visible launchers.

I'm going to play around with a two-funnel version and see what I can come up with.

The Norwegian Fridtjof Nansen Class have an combined Kevlar and rubber protection. Hansen have also an strengthen keel an several trough ship beam, to prevent the ship from breaking apart if it's torpedoed.

heuhen wrote:

A strengthened keel is a good idea...but why the rubber? Is it to protect the Kevlar fibres?

And...as promised, a two-funnelled version:

[ img ]

it's for protecting the Kevlar, but also protecting against shook-wave... apparently, or was it to reduce the shook on the hull it self...

Shipbucket

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