The Impossible Made Possible

When confronted with the challenge of transporting a submarine that supposedly could not be hoisted out of the water and brought safely to its destination, shipping company Jumbo formed a close and innovative partnership with Saltwater Engineering. They faced many challenges, but this cooperation proves that even the most challenging project can be completed.

The submarine Ouessant, built in the 1970s and owned by the French Government, was taken into retirement and docked at a French navy base in Brest. The submarine was used to train students from the Royal Malaysian Navy. In September 2011 a signing ceremony was held for the transfer of ownership to the Malaysian government. The Ouessant was to be transported to Malaysia, where it will become an honorary piece in the Melaka Eco Park at Klebang, Malaysia.

The challenge

Jumbo received the contract for the transportation of the submarine, which first required a detailed plan of how to hoist the submarine out of the water and transport it safely across the world. Peter Jacobs, senior project engineer at Jumbo, explains: “The initial challenge was that very little was known about the submarine. As it was docked at a naval base in France with strict security, it was not likely we could get all the necessary information within the allowed time frame. We had to make a plan on how to get the submarine out of the water, with our first idea being to simply hoist the submarine by using strops, slinged around the submarine and then attached to the hooks of the cranes. Unfortunately we quickly realised this was not possible as the submarine appearedĀ to have a five millimetre thick outer skin and a 35 millimetre inner skin, meaning the outer skin is very fragile and any form of pressure would mean damaging the submarine.”

Two minds are better than one

“Back to the drawing board, as they say”, says Jacobs. “Many other ideas evolved, for instance pouring concrete between the inner and outer skin, so that we would be able to hoist by way of strops as the pressure is spread due to the concrete. Alas, we were not sure if the concrete would reach all cavities between the inner and outer skin and without being able to check this thoroughly, you run the risk of damaging the submarine. Our next option was to create two cradles upon which the submarine would lie and it could be pulled up on. Based on various calculations you can establish a model. The model can then be used to test the effects of pressure and strain on the submarine.”

This was the moment that naval architects from Saltwater Engineering were introduced into the team. Mike Stelzer explains: “Of coursewe were very pleased to be part of this project as this is our area of expertise. We made an initial model of the submarine to look at the options Jumbo had developed, like the use of saddles. This initial idea of traditional saddles had to be discardedĀ as the model proved they would damage the submarine. All in all, there was a lot of going back and forth and our cooperation was very close over several weeks, during which we tried hard to find a solution for this challenge.”

Inspiration

The project turned into high gear when Ruben Menkveld, project engineer at Jumbo, got an idea from the way dolphins are transported. They are placed into a sling, which is then pulled up from supporting beams on both sides of the mammal. Menkveld: “Why wouldn’t this work for the submarine? We developed this idea to engineer two separate cradles, which would support the submarine from its 800 millimetre broad keel beam, from which the submarine could be hoisted.”

Saltwater Engineering generated numerous models to test all the different ideas for the cradles and the impact they would have on the fragile shell of the submarine. Finally the cradles were fully developed and designed after which the cradles were produced and tested by De Haven bv, the Netherlands. Normally, Jumbo prefers welding the joints of the cradle, but because it was impossible to transport the cradles in one piece, bolts were used to connect the separate members. Menkveld commented that the whole assembly resembled a Meccano project, with the cradles being up to 13 metres long and the complete structure having to be put together piece by piece. Jacobs: “Our Malaysian customer wanted to keep the cradle structure to use as a foundation for the submarine in the Eco Park, meaning we had to assemble and transport the structure carefully.”

Complex and well thought out

The actual loading brought along some complex situations. Menkveld: “When you see the loading from your computer, it seems pretty straightforward, in hindsight this was not the case. The submarine was brought to the vessel by tugboat, as the submarine could not propel itself. The first cradle would be lowered into the water after which the tugboat would pull the submarine into position.” Jacobs: “We had two divers in the water, who were the eyes of the project for the people on board the Fairplayer. As the margins are too slight, you need to be sure everything is in position before hoisting the first cradle. Though the whole structure was designed to allow the tugboat and submarine to pass over the cradle without problems, never the less you are talking about a 1,081 ton submarine. After positioning the submarine, we finally had the submarine perfectly in place above the first cradle.”

Securing and hoisting

The first cradle was pulled up to allow some support to the front side of the submarine and make sure it wouldn’t move. When this was achieved, the second cradle was placed under water and pulled underneath the submarine. This again had to be well thought out, as the end of the submarine is broader and the shape is different. The movement of the vessel and the placing of the second cradle created a change in weight and thus the pull on the first cradle had to be monitored continually to keep the vessel stable.

Menkveld: “With the second cradle in the correct position and secure, we could start hoisting the submarine out of the water. We allowed the submarine 15 minutes just above the water, so we could be sure all bolts and joints were secure and settled within the cradle.”

An ‘s’ shape movement

The limited lifting height only made it possible to lift the submarine at starboard side of the vessel, which also meant that the submarine would have to be piloted between the two large cranes of the Fairplayer. The movement had to be done in an ‘s’ shape, because the submarine was too long to fit between the cranes. From crane to crane the distance is around 48 metres, the submarine is 68 metres. Menkveld: “Again, each movement you make causes a balance change for the vessel, so you have to make constant adjustments with ballast water.” The submarine was safely placed into the vessel hold and was carefully secured to the vessel using wood between the strong points of the submarine and the lashings, to ensure no damage. Jacobs: “You can imagine a submarine is one of the last things you want rolling around in your vessel. Safe sea fastening was another challenge we were able to complete and thus the submarine was ready to transport.”

Arrival in Malaysia

The transport of the submarine went according to plan and when it arrived in Malaysia the challenge of unloading it seemed less deeming as Rien Huijbregts, field supervisor at Jumbo, comments: “You know it has been done before, so it seems much less daunting and paired with the fact that the people on board have also placed it safely into the vessel, you feel a little more at ease. The unloading was done in much the same way as the loading of the submarine. We could not sail up to the quay where we would place the submarine, so we used a pontoon which had the trailer for land transportation already placed onto it. The submarine was hoisted onto the trailer and the half hour sail to the quay was undertaken.” The trailer, which had 480 wheels, drove the submarine to its concrete holding, by using its hydraulic pumps. The concrete foundation upon which the submarine would rest, was designed to allow the trailer to pass through and then lower the submarine onto it. The arrival of the submarine sparked much interest in Malaysia, a fine welcome to its new home.

The project that was once deemed impossible was executed perfectly by Jumbo with much help from Saltwater Engineering. Submarines may not be built for lifting out of the water, but careful ideas, inspiration and hard work are just some of the ingredients necessary to complete a challenge like this.

Rebecca McFedries