SureSeals are lubricated by raw water, just like a stuffing box gland, but that is where the similarity ends. The housing is manufactured from a non-corroding reinforced fibre, inside which is fitted an integral self aligning PTFE bearing. The articulated hose, with stainless steel clamps, is matched to each housing and stern tube size. In a twin shaft installation, a crossover lubrication line is fitted between the two seals to ensure a continuity of lubrication and increased vessel availability.

The SureSeal system features a ‘spare’ seal which sits in front of the unit until required. When replacement is needed, perhaps due to mechanical damage or eventual wear, the removable front cap can be separated, the old worn seal cut off, the new one slid into the housing and clamped back into place. This job takes just a few minutes and can be carried out afloat and from within the engine room, even when cramped, thus saving the cost and operational availability lost for a docking.

SureSeals are fully certified by the American Bureau of Shipping for vessels up to 90m long and models are available for commercial vessels to super yachts, fitting shafts from 25mm to 240mm diameter. The MCA has agreed their use on the PLA’s coded pilot boats and SCVs.

The trial was a success and the PLA, which operates over 30 vessels from its marine operations base at Gravesend, is replacing traditional shaft seals throughout its fleet with SureSeals in each craft as it comes in for refit. As Andy Nailor explained, ‘We operate our vessels for between 2,000 to 3,000 hours per year each. Following the success of the Tides Marine SureSeal trial we now fit these seals and, apart from a routine inspection during the regular 400 hour vessel service, the seals have required no further attention.’

Latest to have SureSeals fitted is the PLA’s survey vessel ‘Verifier’, which has 1,100hp Caterpillar C32 engines on two shafts. Packed with smart electronics and with a top speed of over 26 knots, Verifier is used for monitoring and recording the condition of the riverbed and provides soundings for both the PLA and Admiralty Charts. SureSeals help to ensure this valuable work is an ongoing process.

MJ Information No:22619