Triton 1000/2 and 3300/3: 1995 Onwards

Made instantly famous by David Attenborough and the TV series Blue Planet filmed in 2015- 2016, the Triton series of acrylic submarines, capable of diving to 1,000m, are what all marine scientists want to ride in. A fabulous view, superbly manoeuvrable, practical, reliable and well supported - nine in total have now been built (2020). The engineers at Triton have also fully embraced computer control, management and navigation with a fully featured on board PC / PLC system. At the same time along this road, they have pioneered a new and far better method of producing acrylic spheres.

This story started with a conversation in 1998 between myself and Bruce Jones of US Submarines. He wanted a concept of an acrylic hulled submersible that would comply with the current ABS minimum freeboard requirement of 762mm. The JSL subs did not comply but they pre-dated the Rule. Graham Hawkes had got around the rule in his DR1 and 2 with the hatch in the bottom. Bruce thought this would be a hard sell so he asked if it would be possible to lift the entire vehicle high enough to obtain the freeboard required.  I did some sums and produced a sketch of what would turn out to be the 1,000/2 but that is as far as it got until 2005 when Bruce found an interested client.

Triton Submarines was formed with Bruce Jones and Patrick Lahey as equal partners to build the new acrylic submersible. In 2006 the design was fleshed out with the particular client in mind. The sub was to be housed aboard Chris Klein's MV Mine Games which had a maximum lifting capacity of 2,727 kg (6,000lbs). This turned out to be the driving consideration as displacement had to be minimized as far as possible. The hull is 1520 OD and 1400mm ID which gives 300m diving depth in water of 10°C or less. Had we even a little bit more displacement to play with the diving depth could have been much greater.

The sub is characterized by its two ballast tanks on either side above the battery pods. These have enough air to lift the sphere to its half way point easily giving us the required freeboard.  Although there is some visual occlusion to the sides, the forward view makes up for it.

Assisted by John Ramsay who joined us from JFD, this was the first sub we designed and built using 3D solid modelling. Now you would not consider doing it any other way. A new company was formed and the first Triton 1,000/2 was built by Patrick Lahey and his team in Vero Beach Florida. The first boat named Nemo was launched in 2008 and immediately proved a great success, the yacht owner and his captain being well up to this technically demanding task. A second boat named Nomad followed shortly afterwards. These are the two subs you see on Project Baseline being run by Robert Carmichael. Robert's current project with these two subs is named Global Sub Dive. See rmcdive.com

Now that Triton was beginning to get noticed, attention turned to a larger deeper diving version. Early in 2009 Patrick and Bruce set John and I the task of exploring what was possible. The spheres of Alicia were about as big as Stanley Plastics could fit in their Autoclave. The final design emerging in late 2009 required a sphere 2100 mm OD and a wall thickness of 166mm. This would make it the largest submarine sphere ever made and pushed conventional manufacturing methods to the limit.

The larger diameter meant the hull did not need to be lifted to the equator like the 1,000/2 to achieve 762mm but raising the ballast tanks higher would badly reduce the field of view. The question was, could the necessary stability be achieved without the contribution of the ballast tank waterline. Careful analysis revealed that all that was needed was to surface a small platform volume immediately aft of the sphere.  The main tanks could be left submerged and placed as low as possible. This is the reason for the characteristic shape of the 1,000m 3-man 3300/3 submersible.

John Ramsay took the job of lead engineer this time as I was consumed by MSubs work. The first 3300/3 was launched in 2011 and lived up to its promise.  The sub featured in a Discovery Channel documentary filmed in Sagami Bay 2012 titled ‘Monster Squid – The Giant is Real' and again with ‘Shark Week' in 2013, with the narrator none other than Sir David Attenborough. Sir David tried a 3300/3 ride for himself earlier that year on the Great Barrier Reef, and featured in a recent interview between Sir David and President Obama.

New Acrylic Sphere Technology

By the beginning of 2013, 2 years after the order was placed, the second sphere for the Triton 3300/3 was a no show and by this time there were a further four 3300/3s on order. The current supplier had experienced several failures and there was no end in sight. The conclusion was that the conventional manufacturing methods were being used outside their limits so a new way had to be found.

Following conversations between Bruce Jones and the German acrylic manufactures Evonik and Heinz Fritz in connection with windows for the proposed underwater hotel. They were then asked if hemispheres could be thermo-formed from flat plate. Heinz fritz agreed to run a development program and an order was placed early in 2013. The starting point is rectangular block, 3m x 6m and 220mm thick. These are cell cast with the temperature closely controlled in a water bath. The result is a stronger material as the polymer chains have more time to grow. These are machined flat then two discs cut 2940 diameter.  Using a pair of metal dies the discs are thermo-formed into two hemispheres with a minimum thickness of 180mm.  The raw hemispheres are then fully machined, the apertures cut and then polished to a perfect finish. The two halves are bonded with a new thin joint technology that is less visible than the old method and less prone to bubble inclusions.

The result is - by quite a margin - the best submersible spheres ever made. The finish and clarity far better than previously obtained using slush casting, and once the tooling had been made much quicker too. Evonik (now Rohm) and Heinz Fritz continued to supply one sphere every 12 weeks, the Triton shop became quite a production line. Heinz Fritz continues to this day supplying Triton with spheres of various diameters and thicknesses.