Shipbucket

On the Defiant class you've got enough deck space due to the outer hulls that sponsoning out the Phalanx and autocannon just seems silly.

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left over from the superstructure I copied will delete the sponsons.

I cannot help but wonder why this latest vessel is an trimaran. I see no obvious advantages in what it can do, while the type 45 already is the biggest and the most expensive of it's lineage. there can be no additional weapons in the outriggers, the hangar is amidship, and the only thing that seems to be added is boat space and maybe some more living space, at an great cost in materials, design costs and size.

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simply because it look good............................... and in an AU cost isn't a major issue. extra boat space is needed as one of the ships missions is anti piracy and experience with using the type 42's proved more small craft are handy, if having to board ships or intercept multiple pirates on small craft. as stated I have reserved some space aft for the future addition of sylver a 43 launcher to take CAM quads, extra living space is needed to hold extra marines when in use on anti pirate roles. also I wanted to keep all of the Type 45's luxurys like gyms etc for crew. the space in the sponsons can also hold stores, spare for the ships boats, helicopter parts or a whole manor of parts. I want this ship to be truly multi purpose, adaptable and future proof and thus warrant extra cost.

One might choose to use the immense stability reserve to move to a larger or staring SAMPSON. I also see no reason that there couldn't be a VLS block in between two helo hangars, like on a IIA Burke. Extending the outriggers aft to the transom would be a good idea in this case.

RP1 has observed, IIRC, that ship handling in a quartering sea is vastly better with outriggers that extend all the way aft.

I do find myself wondering if the inter-hull segments are as thick as structural requirements would mandate.

Without the mission bays being built into the side of the hangar as on the original type 45 I was hoping to squeeze a wider hangar that could hold two Helo's of Merlin size or at least 2 Lynx.

Shit, two Lynx? You can fit that on a Type 23 already. That's trivial. Two Merlins is essentially the same as two CH-148s, and you can put that on a 50ft-beam Tribal DDG.

Not quite.

Sidehull size is dictated by the required intact stability.
With this fixed, side hulls just aft of amidships (like Triton) have the best seakeeping*
Side hulls right aft have the lowest resistance at high speed, but poor seakeeping**

If you have to have side hulls aft (for resistance or layout), then it is better to make them longer, so that they extend further forward (like LCS2), this reduces the seakeeping problems. But it increases the wetted surface area, so increasing the resistance at low speed.

So for a ship like this, assuming similar operational profile to T45, an arrangement proportionally similar to Triton or VTs Cerberus would be expected, as a balance between the various operating speeds and conditions. No prizes for guessing what the FSC trimaran looked like (before King Speed came along )

RP1

* Generally. If they are too large, however, parametric resonance can occur
** Specifically, very poor in stern seas

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"Yes siree, the excitement never stops." Togusa, Ghost in the Shell

Minimum hangar dimensions for EH101 I have from AW data are:

Length: 16.5m
Width: 7.5m
Height: 5.6m (Recommended 6.9m for maintenance)

So assuming two hangars, a separate passageway (Preferred in the RN) and a centreline VLS gives something like 20-22m beam minimum.

RP1

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"Yes siree, the excitement never stops." Togusa, Ghost in the Shell

Regarding trimaran box structures:

Minimum clearance under the box: 3-3.5m
Internally the box generally has a double bottom and an internal deck. The double bottom has to be big enough to construct, so 0.5m maybe. Deck heights have increased in recent warships to improve outfitting (and operability) and to accommodate modular cabins, improved ventilation, rafting of electronics etc, so may be 3m on No 2 deck (where all the horizontal systems are), so that gives an internal box height of 3.5m for a single deck.

The reduction in box height aft is odd. Everything wants to be on No.2 deck, so more space there is always better. Remember that in a trimaran you actually have a higher void volume fraction as the hull is more pointy (and the people and equipment come in fixed sizes!) so is less efficient in terms of arrangements. Thus a big box is generally a good thing, to fit it all in.

RP1

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"Yes siree, the excitement never stops." Togusa, Ghost in the Shell