Re: [TML] Destroyer tonnage... John Groth 16 Sep 2014 01:52 UTC

Grimmund wrote:

<<snip>>
>
> Spitballing some numbers, I get about ~3000dtons for the Spruance:
>
> http://www.militaryfactory.com/ships/detail.asp?ship_id=USS-Spruance-DD963
>
> gives dimensions of
>
> ength: 563ft (171.60m)
> Beam: 55ft (16.76m)
> Draught: 20ft (6.10m)
>
> and a crew of 393 officers and ratings.
>
>   Side view here:
>
> http://www.the-blueprints.com/blueprints/ships/destroyers-us/7849/view/uss_dd_979_conolly__spruance_class_destroyer_/
>
>
>
> meters, l*w*d
>
> Draught, 6 meters.  If I understand correctly, this is waterline to
> low point of keel:
>
> 172*17*6
>
> Another 5 meters to the deck, above the waterline, estimated:
>
> 172*17*5
>
> And the superstructure, estimated  (this is a total SWAG on my part)
>
> 120*14*6
>
> Check the photo here and add your own adjustments
> http://upload.wikimedia.org/wikipedia/commons/e/e0/US_Navy_030321-N-6141B-006_The_Spruance_class_destroyer_USS_Briscoe_%28DD_977%29_underway.jpg
>
>
>
> totals a little over 42,000 cubic meters, divided by 14.25 is just
> under 3000 traveller dtons.
>
> Thes, this treats the ship as a regular solid body rather than as a
> streamlined body, and does not consider volume lost to streamlining.

A number of years ago, I used the Akins FF&S2 spreadsheet to design the
_Deyo_-class destroyer*, and ended up with a displacement of 3000 dTons.
  This matches the displacement of the _Midu Agashaam_-class destroyer,
so this seems to be the size Imperial Navy planners expect for peacetime
destroyers.

I think I'll do some tweaks to the ship (I last worked on the design in
January 2008 [file version "Deyo2b"]) and do a writeup.

*Note that, _contra_ this Traveller wiki site's page on destroyers,

http://wiki.travellerrpg.com/Destroyer

AuricTech Shipyards equipped the _Deyo_-class with a spinal NPAW mount.
  Why?  Because of some of the sweetest words a defense contractor can
ever hear:

"Cost-plus contract**" :-D

Besides the obvious financial benefits that various cost-plus contract
structures provide to AuricTech Shipyards, keep in mind also that FF&S2
doesn't simply provide a pre-built list of spinal-mount weapons.  FF&S2
allows for spinal-mount weapons of any size, with the primary limiting
factor being the length of the ship on which the spinal-mount weapon is
to be installed.  As such, AuricTech Shipyards has designed ships that
mounted "spinal" NPAW weapons that were smaller than HG-based NPAW bay
weapons (the advantage being that spinal-mount weapons are less
vulnerable to damage when using Bruce Alan Macintosh's Military Combat
System for T4 ships that are designed using the FF&S2 rules).

**See

http://en.wikipedia.org/wiki/Cost-plus_contract

for details, with the stipulation that AuricTech Shipyards generally
will only accept cost-plus-fixed-fee or cost-plus-award-fee contracts
for Imperial forces.  Private buyers who are willing to sign a
cost-plus-percentage-of-costs contract will receive the most exquisite
vessel their CrImp can buy (and our Sales and Finance Department is
quite capable of determining how many CrImp a given buyer can afford).