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Berthon Boat Company to Restore Motor Gun Boat 81

November 8, 2017

1942 MGB 81 71.5ft Motor Gunboat

1942 MGB 81 – 71.5ft Motor Gunboat – Portsmouth Naval Base Property Trust (PNBPT)

Berthon was recently awarded a contract by Portsmouth Naval Base Property Trust for the restoration and re-engining of the famous Motor Gun Boat 81 (MGB81)

Berthon’s history with the Motor Gun Boats (MGB) and Motor Torpedo Boats (MTB) goes all the way back to 1939, when numerous MGB and MTB hulls and complete boats were built or fitted out at our boat yard during World War Two. This adaptable hull design allowed the vessel to be converted between a torpedo and gun boat variant depending on upcoming missions.

Details of Berthon and Lymington’ s proud history during the war effort will form later blogs, but meantime a register of boats built by Berthon from 1939 – 1945 can be found here. Further history can also be found by visiting Lymington St Barbe Museum.

As well as this history, Berthon’s experience was a key factor in MGB81 being restored at our shipyard. Berthon’s traditional shipwrighting experience in restoring and refitting boats at our state of the art facilities is unrivalled in the UK, coupled with our award winning apprenticeship scheme ensures these skills are also passed on to the next generation.

Further information on our Apprenticeship scheme can be found here.

MGB 81 Motor Gunboat arrival into berthon and in our hoist

MGB 81 is a 71.5ft Motor Gun Boat built by the British Powerboat Company for the Royal Navy and launched on 26 June 1942. When built, she was among the fastest boat of her type in the world and capable of speeds in excess of 42 knots, but considering her age, with the new engines she will probably be limited to 34 knots. MGB 81 and her sister vessels were involved in action in the English Channel, attacking enemy torpedo boats and landing secret agents on occupied soil. She was later involved in D-Day operations. MGB 81 is unique as she is the only restored and operational example of a Royal Navy Coastal Forces MGB which saw active service in WW2. As a result of the restoration techniques used, she will retain most of her original performance capabilities but will now be stronger, lighter and require less maintenance.

She arrived at Berthon in early July 2017, and was lifted to Berthon’s M-Shed with the intention of undergoing a survey and to allow time for her hull, deck and superstructure to fully dry out. She was then moved to our West Solent Shed where preparatory work began making the vessel safe for working ashore, with the engineering systems having been previously surveyed and assessed and a detailed engineering report given to the owners.

The refit will strip her from stem to stern, and replace the structural frames and longitudinal stringers in pairs so as to safeguard the original hull and fittings and keep it as original as possible. One of the largest jobs will include replacing the 3 MAN 835hp engines with 3 new, Mermaid Marine supplied, FPT C13 825hp diesel engines. Both Berthon and the PNBPT want to keep MGB 81 as original as possible. However the replacement engines will be more reliable, fuel efficient, lighter than the originals.

As with any substantial refit work at Berthon, MGB 81 underwent a comprehensive assessment prior to the project plan being consolidated and put in place with key items being put into an inventory database, logged, photographed and stored.

MGB 81 Motor Gunboat in one of berthons sheds

The current main areas identified for work include:

Engine Room

  • Removal of old MAN 835hp engines
  • Fitting of new FPT C13 825hp diesel engines
  • New gearboxes
  • Installation of new exhaust system, fuel system and seawater cooling system
  • New shafts and prop
  • New batteries
  • New fuel tanks
  • New 240v generator
  • Engine room ventilation upgrade
  • Installing an engine room fire extinguishing system
  • Installing engine room fire alarms
  • Servicing and upgrading hull valves and fittings
  • Servicing of all seacocks

Before any work in the engine room can begin, the aft section of deck house and superstructure, gun turret & mounts and the rear gun will have to be removed in order to gain access to crane out the engines. The deck house will then have to be replaced on completion of the engine installation.

MGB 81 Motor Gunboat original engine bay before removal

Helm & interior

  • New engine displays & controls
  • Steering system
  • AIS system
  • Installing glass deck lights

The new engine displays will be analogue gauges so they are in keeping with the boat, and all digital displays will be mounted out of sight below deck. The visible part of the engine controls will be re-used and will operate the electronic controls which again will be hidden below deck.

MGB 81 Motor Gunboat original helm before restoration and upgrades

Repairs and Paint

  • Complete repaint of vessel topsides, deck, antifoul and coach roof
  • Major replacement of structural frames and longitudinal stringers
  • Portside hardwood rub rail
  • Deck sheathing
  • Transom repairs
  • Deckhouse repairs
  • Deck hatches repairs

MGB 81 Motor Gunboat original interior before restoration begins

The aim is to complete the restoration and undertake trials in mid-2018, after which she will be on show at the Portsmouth Historic Dockyard along with other famous historical vessels including HMS Victory, HMS Warrior and the Mary Rose.

Progress and updates on this project can be followed on our website, or register for our news blog here.

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