Marlin Submarines S103 “Lula”: 1997-8

Lula, Portuguese for Squid, was commissioned by FRN, an ocean science foundation based in the Azores. I was approached by FRN in 1996, a simple arrangement was agreed and work started in January 1997. The team I put together for this sub was one of the best ever. Design and project management was shared between myself and Patrick Lahey now President of Triton Submarines in Florida. We also had Steve of Polypressions for the GRP of course, Charlie Sillett whose association with submarines goes back to the days they used them in the offshore oil industry, the Australian Dave Macalone who always had us in stitches and my younger brother John.

A fixed price deal was agreed with ABS in London, an arrangement that worked well, for us at least, but we had just over a year to complete the project. The submarine had been billed to appear in the Portuguese pavilion at the 1998 World EXPO in Lisbon.

One of the objectives was to find shallow hydrothermal vents and be able to more easily study the unique fauna that exists there. The hull was therefore designed for 500m and pressure tested to 625m in Slingsby’s chamber in Kirkby Moorside. This 20mm thick internally framed hull was built by Overlasko in the Netherlands.

To minimise the surface support required in operation a diesel electric propulsion system, my third to date, was planned based round an engine specifically designed to run on pure sunflower oil.  This was in the day when it was thought that growing diesel fuel would be the answer to global warming and our reliance on fossil fuel. It was then shortly realised that the sunflowers displaced normal agriculture with the inevitable bad consequences. But in the meanwhile, the exhaust smelled like someone was cooking popcorn. The sub could re-charge its own battery and with the clutched on-board compressor could re-charge its own air banks.

The main feature of this sub was the full diameter bow viewport. Actually a 150° spherical sector so almost a hemisphere. The problem with full hemispheres is that you have no way of retaining them other than an integral flange which shortens its rated life from 20 years to 10 years due to stress concentration. The unobstructed view was unprecedented on such a deep diving submersible. There was also a matching hatch window to navigate on the surface.  

We had to be quite inventive to keep costs down, building our own hydraulic manoeuvring thrusters and sticking to the ‘keep the machinery on the inside’ principle which is the key to reliability. A 5-function manipulator was designed specially by Hydrolek to wrap round the front part of the skid when stowed.

Lula went to the Azores later that year for completion and ABS certification and enjoyed a very useful period of work until the upgrade in in around 2009-10. The 500m hull was sold to Ocean Gate and incorporated in a new submersible working along-side XPC15. Lula received a new 1000m hull made from duplex steel. A foretaste of things to come, the new viewport was made by Evonic and Heinz Fritz in Germany.