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Old April 25th, 2011, 07:00 AM
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Default Traveller Turret Terminology vs Historical Terminology

Raised in another thread was the view that a historical "turret" = a Traveller "turret". The implication being that the authors intended a strictly historical interpretation of "turret" to be applied to space going craft in Traveller.

This has lead me on quite an interesting diversion to determine "historical" terminology. The documents I am reading appear to be scanned copies of US Navy documents collected by an enthusiastic US Navy seaman (retired?) and published on the web. The documents I have looked up cover the period 1937 to 1971 and are essentially scanned training manuals and the like.

I have selected quotes from a variety of US manuals. Whilst perhaps limited only to a US perspective, for the purposes of demonstrating a Traveller TL 10-15 space going "turret" does not equal a TL 5-8 wet navy "turret", it should suffice given the authors of Classic Traveller are US citizens.

This is the opening paragraphs of;
Naval Ordinance and Gunnery",
Volume 1 Naval Ordnance,
Prepared by the Department of Ordnance and Gunnery,
United States Naval Academy, 1957 edition.

This 'basic textbook' was used in the training of US Navy Midshipman and Officers.
(nb: they are all fairly large PDFs)

Chapter 7, Turret Installations
The type of gun emplacement called a turret is, in
general, that in which several heavy guns of at least
6-inch caliber are mounted in an armored structure
which is revolved on rollers by suitable machinery, the
guns being elevated independently of the structure.

The Bureau of Ordnance designates ordnance equipment
as gun mounts or as gun turrets according to the
division of cognizance between that bureau and the
Bureau of Ships. In general, if the equipment is massive
enough to require assembly of parts on the ship
as it is being built, it is called a turret. If the assembly
is made in a gun shop and then hoisted aboard as a
complete unit, it is called a gun mount.
Of note is that US Navy parlance circa 1957, has it that Turrets 'are massive enough to require assembly of parts on the ship as it is being built'.

Also of note is that guns are 'mounted in' the turret and that this definition of 'turret' does not preclude the turret having the components of 'gun mounts' as part of the assembly. A peruse of any of these manuals and thier many photos and illustrations will show you the Deck Lugs (carrage) and Gun Slides used to mount the guns themselves and together called the gun mount. A BB turret has from two to four gun mounts.

This next extract is from;
15 OCTOBER 1967

Chapter 1, Geneneral Description of the Turret
Turret Arrangements and Differances
Virtually identical, each turret comprises a gun
house and rotating structure, a barbette and fixed
structure, magazines, and ordnance installations.
These differ only in minor details, adapting each
turret to its ship location and the fire control plan.
The gunhouse, 50.63 feet long with a maximum
width of 36 feet, is mounted above and attached to
the rotating structure. Cylindrical and conical in
section, with a maximum diameter of 35 feet, the
rotating structure is supported by a roller path and
consists of six floor levels. Turret II has a seventh
floor level which is a part of the fixed structure.

The rotating structure, protected on top by heavy
armor plate of the gun house, is enclosed within the
upper and lower barbette sections. Cylindrical and
made of heavy armor plate, the upper barbette and
armor deck plates protect the rotating structure,
roller path, and foundation. The three upper barbettes,
each 37.25 feet in diameter, have different
heights because of trunnion axis elevation differences.
Conical and made of heavy steel plate, the lower barbette
is a supporting structure for the upper and differs
in height for each turret.
Of note here, is that a turret comprises the entire assemblage over 6 or 7 deck levels, including rotating and fixed components and ordanance instalations. Elsewhere it notes the entire turret assemblage is around 2000 tons.

US Navy Gunhouse is similar to a Turret in Traveller, in that both may hold 3 weapons and both are armoured, but there is a huge differance in scale.
US Navy Turret or Turret Mount might losely be construed in Traveller as Turret plus Hardpoint. Very loosely, as the weaponry in Traveller turrets is intended to be easily swapped/replaced and of course in Traveller, turrets themselves are easily swapped, do not reach into the bowels of the ship and do not weigh anything like 2000 tons.

Firepower wise a BB wet navy triple turret is more akin to 3 Bays in Traveller. Of course that ignores the obvious structural differances between Bays & Turrets. However, firepower wise, there is no space-going Turret equivilant in Traveller for 19th & 20th century wet navy turrets.

The next extract is from;
Priciples of Naval Ordnance and Gunnery
Training Publications Division
Washington DC, 1971

Chapter 5, Guns, Gun Mounts and Turrets
Turret Structural Arrangement
last paragraph

The general principles of a gun mount's major components discussed early in this chapter, also apply to the turrets component's with one major differance. In a turret, the slide, housing and gun barrel are supported by girders (fig 5-43). They serve the same purposes as a gun mount's carriage cheeks shown in figure 5-3.
BB turrets also contain gun mounts to allow the mounting of guns within the turret. Without the slide, housing and deck lugs (together forming the gun mount) the gun cannot be mounted.

In summary, the US Navy mounts guns in armoured Gunhouses that form the upper part of the turret assembly which weighs on BB's around 2000 ton. It is so large the turret has to be assembled whilst the ship is being built. A Traveller firepower equivalent to a BB triple turret, might be 3 Bay weapons.

In contrast, a Traveller space going turret 'weighs' 1-3 tons. Is easily removed and replaced at any starport, can hold a variety of weapons and sits on top of a surface hardpoint that takes up no interior space.

And all US Navy turrets, large and small, have the required components of gun/weapon mounts which allow the mounting of guns inside the turret.
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