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Updates on the 1942 Motor Gunboat MGB81

August 3, 2018

Superstructure Repairs and Repaint, Fire Alarm Installations & Fitting New Instruments

Deckhouse repairs

Deckhouse repairs have now been completed. As ever with rot it is best to deal with it as soon as it appears because moisture will travel creating far greater expenditure in the future. Since this vessel is to be a working museum piece and therefore on the water, it is vital that all rot discovered is eliminated at this stage.

Having cut out the rot, we then glue a section plywood to fit which is laminated over with an epoxy resin. A green peel ply is then laid over, to be removed when dry giving it a cleaner and smoother finish, filled and faired with epoxy, sanded back and primed ready for a new coat of paint along with the rest of her superstructure.

Peel ply is a tough and finely woven nylon fabric treated with a release agent and used to separate the absorber breather and vacuum bag from the epoxied laminate during the vacuum bagging processes but it’s also used in hand lay-up uses to allow more pressure when squeegeeing and to protect the lay-up from contamination.

The fabric sheet is draped over the epoxied surface allowing excess epoxy to bleed through; Once it has dried, the fabric is peeled off the laminate, and what’s left behind is a perfectly smooth surface that’s ready for a quick sanding, or for the next round of epoxy, with no runs, no sagging and especially no low spots.

While repairing the superstructure behind the steps, leading to the helm, we found that the frame around the window was also rotten. This has also now been repaired and the portlight has been replaced by two of our female apprentices (above and below photos).

Superstructure Repaint

With the repairs to the deckhouse and superstructure complete we were able to begin sanding her topsides and superstructure with all windows, instruments lights and the horn masked off, waiting for correct temperature to apply the Jotun Conseal, a one component, physically drying acrylic coating with a matt finish. We used the original light admiralty grey for the topsides and superstructure and dark admiralty grey for the decks and top of the superstructure.

It is a high build product, meaning just one or two coatings are needed, high-build coatings also generally have a high resistance to water vapour permeability, better ‘crack-bridging’ capabilities, which guarantees a sufficient coverage of voids and other small surface imperfections which could serve as an entryway for water. It is also durable, attractive and smooth while also being resistant to wear. It is also fast drying which allows for over-coating in a short period of time and can be used directly onto metal, which is especially useful for the gun turrets.

Finally, from a cosmetic perspective this product was selected because it provides an authentic hand applied non-gloss finish to keep the original 1942 feel and look.

With the 3 new Mermaid FPT 825hp 6 cylinder engines successfully ensconced within the engine room the A-frame cranes have been redeployed elsewhere in the boatyard and staging adorns MGB81’s topsides are ready for prepping; not a small task!

Engine Instruments panel

On the bridge, the new engines require a whole new set of instruments and in order to keep the original 1942 feel the delivered modern housings have been eschewed (with apologies to the engine manufacturers!)

Installing fire alarms

We previously mentioned the new engine room fire suppression systems (you can read about them here) but to completely comply with modern safety regs, fire alarms have also been installed in the cabins. Fire prevention is always your main protection from a fire on-board, but a smoke alarm can be your next best line of defence, predominantly if you sleep aboard or carry guests. Smoke from a fire will affect your ability to breathe, a sensation similar to drowning, and with only two to three breaths of toxic smoke you could be unconscious. A working smoke alarm, of the right type, can warn you very quickly of the danger and provide you with those extra precious seconds to escape from what is essentially a wooden tinder box.

What’s Left to do?

Back in December you may remember we removed the 3 MAN 835hp engines; with the new engines in place an 8^th video is soon due showing you the in-depth, step by step process of how it occurred.

Project Progress; here

Trials are scheduled in the Autumn, after which she will be on show at the Portsmouth Historic Dockyard along with other renowned historical vessels together with HMS Victory, HMS Warrior and the Mary Rose.

Outstanding jobs still include;

Helm & interior