DONATE A METRE OF NEW RUBBING STRAKE!

Once the new steel has been welded in to support the timber rubbing strake, we need to buy the wood! The original was English elm, which is now unobtainable, but we can get hold of Douglas fir which will perform as well. However, it costs £100 a metre. We need at least 5 metres to do the port side. One member has already donated enough to buy one metre. Any further donations, whether to buy a whole metre, or a few centimetres, will be gratefully received!

To donate, please contact our treasurer, Chris Nursey 01268 768474, 07810132232 or email jillandchrisn@supanet.com

2024 WORK DIARY by Chris Nursey

After we returned from the Classic Boat Festival at St Katharine’s Dock in September 2022 we took the decision that the port side rubbing strake had reached the end of its useful working life. Much of the wood was rotten so offered no protection to the hull plates if we bumped alongside and the steel banding was heavily corroded in places so that it split when stressed. All we had to do was remove the banding and rotten wood, make minor repairs to the supporting angles, replace the wood with new and fit new ‘D’ bar banding. A task that the volunteers had undertaken on the starboard side of the vessel.

However, once the wood had been removed, the full extent of the corrosion was quickly revealed with much of the underlying steel no more than thin lace. As the surface was chipped back, holes soon appeared, mainly in the bunker area below the deck level but for much of the length of the area above the deck. The volunteers soon realised that the task need to be undertaken by more competent fabricators. Over several months various welder fabricators were contacted. Some failed to keep an appointment to estimate for the task, others refused the job as being outside their scope of work. In June 2023 we eventually found a small business willing to undertake the work at an affordable price. The expected start date was to be late August 2023 but due to poor weather, the start was delayed until November 2023 when a lot of the corroded metal was cut away.

Unfortunately, more bad weather further delayed work and it became obvious that the repair was beyond the expertise of our chosen contractor.

Fast forward to April this year and our decision to secure the future of Portwey by transferring the tug to The Steam Boat Trust set up by Chris Bannister ,the owner of the Steam Tug Challenge. Chris, a coded welder and CEO of Chris Bannister Engineering Ltd visited Portwey to make a very detailed assessment of the work required to repair the corrosion to Portwey’s hull. The more corrosion we cut back, the more damage we discovered and it soon became very clear that much more of the hull needed to be cut out before sound material was reached that new plate could be welded to.

New steel plate was ordered, which had to meet the MCA specification of A1 which is more malleable and has a greater corrosion resistance when in salt water. Unfortunately with the closure of blast furnaces in the UK we can no longer manufacture steel of this quality, so it had to be ordered from either Germany or Sweden the only two countries in Europe that still produces this shipbuilding steel.

Whilst we waited for the steel to be delivered, work began preparing the boiler for inspection which took place on 22 July this year. The boiler passed this first examination with the usual concerns noted that there are some scab pits on the tubes that need monitoring and the main steam pipe will need annealing in the near future. The boiler has now been reassembled and needs filling with water ready to raise steam. This can’t happen until the repair to the hull is complete as the tug will then sit too low in the water to allow access to the repair area.

After all our holidays were out of the way, work started in earnest to cut out much of the corrosion and fabricate plates to be welded into the void spaces. Chris Bannister and several of the Challenge volunteers attended Portwey for six days in the second week of November to start the welding work.

The corrosion above the deck extended to the rivet line where three plates come together and have, over the years, created a rust cell between them. . This has meant that the white line shown in the picture to the left has had to be cut away so good metal could be reached.

In the bunker space, more corrosion was also found where another rust cell had been created when a doubler plate had been added to the outside of the hull to address areas of thinning caused by the acidic corrosion in the bunker from the coal and salt corrosion on the outside as a result of wind and water acting on the hull. The frame is also to be replaced. The bright white band that can be seen in the photo is daylight where the corroded hull behind the rubbing strake has been cut away.

With much of the preparation work completed, sections of new plate needed to be cut to size, fitted and then welded into place. To reduce the heat applied in a single area , three to four hundred millimetre lengths were welded, a section left and the next length welded. Each short length of weld was then joined up once the area had cooled, in this way distortion and integral stresses were reduced.

The next stage of the repair is to replace the angles that support the wood of the rubbing strake and eventually replace the wood.

Originally this would have been English elm but this is no longer available at a cost that we can afford so we are using Douglas fir as it has similar characteristics and density to elm but only costs a fraction of the price at £100 per metre. We need 5 metres of the 150mm square. If you want to sponsor a metre, as one member has already done, please contact Chris Nursey or any of the trustees.

We still have copies of our booklet “Portwey, A Pictorial Celebration”, containing a detailed history and description of the tug, available for £5 plus postage. To order one please email: stportweymembership@outlook.com.