Introduction
SpiralWeld™ was contacted by an organisation that operates a UK wide fleet of all-weather rescue craft, completely funded by voluntary contributions. They were searching for a more cost-effective option to purchasing new propeller shafts as the short mean time to failure they were experiencing, factored with a large number of vessels, made for an expensive combination. SpiralWeld offered a solution which was more cost-effective, had a shorter lead time and increased the mean time to failure of the Propeller Shafts.
Investigation
In conjunction with our client’s in-house engineering department, possible ReManufacture and ReManufacture plus options were discussed, and a selection of test pieces were prepared to examine the repair feasibilities. The test pieces were then subjected to extensive and lengthy tests for strength, reliability and sea water corrosion. The outcome of these tests showed the methods we had used reduced corrosion and erosion. Furthermore using our extensive experience, we ascertained a solution to improve the crevice corrosion resistance characteristics of one of these Propeller Shafts.
We have helped restore propeller shafts for three classes of all weather boat, Severn, Trent and Tamar. All classes endur extreme loads and strains in services and consequently a high level of engineering was required in developing a durable recovery process. Specification of each class are listed below.
| Type of Lifeboat | Length of vessel | Engine power | Prop shaft length |
|---|---|---|---|
| Severn-class | 17.3 Metres | 2 Caterpillar diesel engines producing 1250 HP, at 2300 rpm | 4.3 Metres |
| Trent-class | 14.3 Metres | 2 MANN diesel engines producing 850 HP, at 2,300 rpm | 2.7 Metres |
| Tamar-class | 16.3 Metres | 2 Caterpillar diesel engines producing 1,001 HP, at 2,300 rpm | 4.1 Metres |
Conclusion
Our success can be measured by the number of SpiralWeld™ ReManufactures propeller shafts; now in excess of 300, and we are seeing increasing volumes of shafts for repair. We feel proud knowing that our technology is helping the people who protect our British coasts.
Our recovery solutions are transferable to numerous other propeller shafts from various types of vessels and can be utilized for several other marine components including; Rudder Stocks, Stabiliser Stocks, Stern Tube Seals (deep sea seals).
If you are looking for a more cost-effective solution in the short and long term then please do not hesitate to contact us.