Series 3 Deltic engines

The T18-37K turbo-charged Deltic engine was producing 3,100 bhp power output from the same basic triangle.  Also on the drawing board were a variety of proposed Charge Cooled engines and even a completely redesigned 24-cylinder Deltic in diamond form.  A further redesign of the engine block was required and the Series 3 Deltic was created.  The main feature of the Series 3 engines was the return to a fully-cooled cylinder block along with strengthened cylinder liners.

The first Series 3 engines were the remaining 129 E239 Deltic T18-37K producing 3,100 bhp.  This engine continued to be supplied to the Royal Norwegian Navy but also now to the US Navy who had taken delivery of two ‘PTF Nasty’ Class MTB’s from Norway, PTF3 and PTF4 in January 1963.  They eventually purchased a total of 14 Nasties PTF3-PTF16 which saw active service during the Vietnam War.  These boats had 6,200 bhp to propel them at speed up to 45 knots.

Not to be outdone, in 1961 the Japanese Maritime Self Defence Force purchased three T18-37K engines to fitted into a new three engined fast patrol boat constructed by Mitsubishi Shimonoseki. With a total power of 9,300 bhp PT10 had a maximum speed of 48 knots.  A claim for the fastest diesel engined boat was claimed after the initial trials programme was completed.
Six ‘Velarde’ Class vessels were also constructed by Vospers for the Peruvian Navy and fitted with two T18-37K engines in 1965.  They were used for coastal patrol, air-sea rescue and fishery protection duties.

Finally from 1967 further fifteen and eight engines were supplied to Trumpy and Sewart Seacraft respectively.  Trumpy produced six Tjeld craft under licence PTF17 – PTF22.  Sewart Seacraft manufactured an updated design with an aluminium hull named the Osprey Class  PTF23-PTF26.

E263  Deltic CT1842K
An 18 Cylinder, charge cooled, turbo-blown engine for MTB duties with integral reversing gearbox. 3,700 bhp @ 2,100 crpm.  This was the most powerful Deltic engine to enter service with 24 being produced for the Indian Navy’s Seawards Defence Boats and capable of 50 knots.  These engines were manufactured by Paxman’s who had taken over Deltic production in 1970 with the first engines delivered in 1972.

During the late 1970’s the Royal Navy designed a new Mine Counter Measures Vessel with a glass reinforced plastic hull.  The Hunt Class MCMV requirement specified engines with an even lower magnetic signature than the existing Deltic 18-7A engines fitted in the Ton Class Minesweeper. The new engines were designed and manufactured by the Napier Deltic team at Paxmans.

The main feature of these 9-cylinder Deltics was that the crankshafts and connecting rods were now manufactured from stainless steel.  This effectively reduced an already low magnetic signature even further making the engines ideal for use in mine counter measure vessels.   Thirteen Hunt Class MCMV’s entered service between 1980 and 1989 and are actually the largest warships of glass-reinforced plastic (GRP) construction.  The Hunt’s went through an upgrade between 2012 and 2016 seeing the Deltic engines replaced by Caterpillar C32 engines marking an end to the Deltic engines’ service.

E276 Deltic 9-55B
A flange mounted generator engine for M.C.M.V. 750bhp @ 1,400crpm.

E280 Deltic 9-59K
M.C.M.V propulsion engine. Non magnetic with gearbox. 950bhp @ 1,700crpm.

The Deltic engine design was first fitted in the Dark Class patrol boats and finally completed Royal Navy service 65 years later in 2017 when Hunt Class Mine Counter Measures Vessel HMS Atherstone was decommissioned.  This is the longest any propulsion engine design has been in operation with the Royal Navy.

Survivors

The sound (and feel) of Deltic engines can still be seen and experienced today.  Along with the prototype DELTIC, six British Railways Class 55 locomotives are preserved several of which still run on the main line.  Furthermore a Class 23 Baby Deltic locomotive is being recreated fitted with a T9-29 9-cylinder turbocharged Deltic engine.  Royal Norwegian Tjeld Class P380 is on display in the Royal Norwegian Navy Museum and there are several similar ‘Nasty’ Class MTB’s in museums around the USA. The incredible Deltic powered FDNY ‘Superpumper’ is preserved at the Antique Toy and Firehouse Museum in Bay City, Michigan.

During the late 1970’s the Royal Navy designed a new Mine Counter Measures Vessel with a glass reinforced plastic hull.  The Hunt Class MCMV requirement specified engines with an even lower magnetic signature than the existing Deltic 18-7A engines fitted in the Ton Class Minesweeper. The new engines were designed and manufactured by the Napier Deltic team at Paxmans.

The main feature of these 9-cylinder Deltics was that the crankshafts and connecting rods were now manufactured from stainless steel.  This effectively reduced an already low magnetic signature even further making the engines ideal for use in mine counter measure vessels.   Thirteen Hunt Class MCMV’s entered service between 1980 and 1989 and are actually the largest warships of glass-reinforced plastic (GRP) construction.  The Hunt’s went through an upgrade between 2012 and 2016 seeing the Deltic engines replaced by Caterpillar C32 engines marking an end to the Deltic engines’ service.

E276 Deltic 9-55B
A flange mounted generator engine for M.C.M.V. 750bhp @ 1,400crpm.

E280 Deltic 9-59K
M.C.M.V propulsion engine. Non magnetic with gearbox. 950bhp @ 1,700crpm.