Posted: 30th August 2016
Top 10 considerations in newbuilds to allow for future underwater services
Over the past few years, our underwater services team has had the benefit of supporting our colleagues involved in newbuild planning and specification. I say benefit because it has given us an insight into how with a little forward thinking at the design stage, owners could make substantial savings in the long-term.
We have observed that many shipyards are not really building vessels to prepare for future underwater activities. Having serviced over 1500 vessels here are my top 10 considerations, over and above the standard IACS rules. These if incorporated into the new-building programme, will reap returns in the future:
- Locate any hull penetrations such as ICCP anodes, reference cells, transducers and so on in easy to access compartments – for example not in flooded compartments such as fuel tanks
- Place wet connectors on transducers, echo sounders and other such electrical connections with internal cofferdams or conduit that extends above the water line to allow for diver friendly afloat exchange
- Rudder pintle clearance access – if the area is covered by a door, make sure the door is hinged and has sufficient diver access (minimum 400mm diameter). In addition try to avoid welding the access plate to secure in place. Use securing bolts, which can easily be removed and reinstalled in-water
- For tail-shaft wear down measurements, make sure access holes in the rope guard are large enough for the diver’s hands and equipment. Place them centrally above the measurement positions. The minimum size for hand holes is around 200mm diameter
- Consider installing a bolted type rope guard allowing for easy removal and installation rather than a welded type
- Have all sea chest gratings secured by bolts only and have all gratings hinged
- Mark and log the size of all securing bolts
- Count and log all drain holes, including the size
- Create an access point into thruster gratings (small door), allowing divers to access into the tunnel (600mm x 600mm minimum)
- Consider bolted sacrificial anodes rather than welded types or alternatively ICCP units.
Finally, prior to launching the newbuild make a full photographic report of all external apertures and fittings such as sea chest arrangements, overboards, transducers and thrusters and so on. These should have a clear numbering system so that divers can easily identify them in the future and can be available on board the vessel to be used when required for diving operations.
Want to know more? Drop me a line or if you’re going to be at SMM in Hamburg – come along and have a chat. I’m going to be in the Kopenhagen Room, hall B3 between 0900 and 1300 on Tuesday 6 September and you can also visit us on our main stand in hall B2, booth 200 throughout the event.