View source for 18-in Fiume Mark III Torpedo

[[File:ARTS1904Plate10.jpg|thumb|600px|'''18-in Fiume Mark III'''{{ARTS1904|Plate 10}}]]
[[File:ARTS1908Plate11.jpg|thumb|600px|'''18-in Fiume Mark III** H.'''{{ARTS1908|Plate 11}}]]
The '''18-in Fiume Mark III Torpedo''' was a torpedo manufactured by Whitehead from 1904.{{ARTS1904|p. 28}}

==Development==
It seems likely that this torpedo was a productised version of No. 401, one of two "new" Whitehead torpedoes being tried out in 1903;  the other, No. 398, had an R.G.F. tail and so would seem unlikely to be dubbed "Fiume" type.  It is clearly stated that an order was being contemplated.{{ARTS1903|pp. 53-4}}

In 1904, 100 were on order from Whitehead's Weymouth factory.{{ARTS1904|pp. 28, 41}}

In 1919, it was approved to break up all 18-in Weymouth and Fiume torpedoes.{{ARTS1919|p. 11}}

==Particulars==
===Mark III===
These are detailed in the ''Annual Report of the Torpedo School, 1904''.{{ARTS1904|pp. 41-2}}

At 60 degrees Fahrenheit, they made ~32 knots to 1,000 yards, 28.63 knots to 1,500 yards, 25.18 knots to 2,000 yards, and ~20 knots to 3,000 yards.

Total length 16 feet 7.4", maximum diameter 17.7".  Initial pressure of 2,100 psi (106 pounds air) yielding a charged weight of 1,406 pounds.

The warhead weighed 280 pounds without a pistol (6.8 pounds additional), carrying 205 pounds of wet guncotton and 9 pounds of ballast.

The 4-cylinder FIume type engine weighed 87.5 pounds.  The 43 square inches of piston area drove through a 3.544" stroke.

They were to be passed at 2,00 yards range, the H.B. model being approved for 25.25 knots +/- .25 knots.

===Mark III*===
In the 1905-06 fiscal year, 100 H.B., 22 S.L.L.R. and 114 S.L.S.R. torpedoes were ordered from Whitehead, though the Hook Bracket torpedoes had their air vessels elongated and were dubbed Mark III**.{{ARTS1905|pp. 12, 18,19}}

The head was 4" shorter, 34.83 inches from joint to joint, and that length being put into the balance chamber (bringing it to 27.622 inches), and the air vessel made .426 inches thick rather than .433 inches.  The S.R. torpedoes were 33.5 knots +/- .25 knot to 1000 yards, and the L.R. models 26.5 knots +/- .25 knots to 2,000 yards.

===Mark III* H.===
I created this section with a bad reference.  Upon further checking, I cannot see that any Fiume torpedoes prior to Mark II** were retrofitted with heaters.  A 1908 source indicates that at that time, R.G.F. Mark VI and Fiume Mark III**s were the be the earliest so enhanced.{{ARTS1908|p. 18}}

===Mark III**===
In the 1905-06 fiscal year, 100 H.B. Mark III* torpedoes on order from Whitehead were dubbed Mark III**, as they incorporated an air vessel of a foot greater length (88.771 inches), lengthening the torpedo by a foot in order to seek greater speed.  The balance chamber was reduced to just 15.622 inches.  The air vessel was thinned to just .37 inches, yielding 27.75 knots +/- .25 knots to 2,000 yards &ndash; an increase of 1.25 knots over the Mark III*.  Altered counter gear and the abolition of S.F. fins also were also new features.{{ARTS1905|pp. 12, 18,19}}

In the 1906-07 fiscal year, 144 H.B. models were ordered, along with 40 S.L. models, split between L.R. and S.R. configurations.{{ARTS1906|p. 8}}

F. Mark III** V.B. torpedoes were supplied to {{UK-Gorgon}} and {{UK-Glatton}} for their 18-in submerged Elswick tubes.  They had an S.R. setting of 26.25 knots to 2,000 yards and L.R. 19 knots to 4,000 yards.{{ARTS1916|p. 46}}

===Mark III** H.===
In 1913, these were to be given to {{UK-Shannon}} and {{UK-Cochrane}}.{{ARTS1913|p. 8}}

Its overall length including 4.5-in long pistol was 16 feet, 7.466 inches (see Plate).{{ARTS1908|p. 18}}

==Footnotes==
{{reflist}}

==Bibliography==
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==See Also==

{{CatTorpedo|18-in|Fiume}}