Incat^® Catamaran Expansion Joint

Incat are a world renowned Australian shipbuilder known for producing optimal, lightweight ship solutions for ferry operators, special service providers and militaries. As a global leader, Incat are constantly seeking new opportunities to streamline their manufacturing process and increase the efficiency, performance and durability of the craft they produce.
In 2014, the team at Incat identified inefficiencies in the installation procedure of their expansion joints. These expansion joints are installed between the vessels’ internal cabin superstructure and the hull.

This internal cabin is where the vessels passengers reside during transportation. It is suspended and insulated within the hull using isolation mounts and expansion joints to absorb excess energy from waves during transportation. This is essential for ensuring a smoother journey for the passengers.

As the cabin superstructure is separated and suspended within the hull, a gap exists between the two structures. This gap is sealed with a continuous, flexible and water-tight expansion joint. This expansion joint must create an endless seal around the craft to ensure water cannot enter the internal structure of the vessel.

At the time, Incat was purchasing a flame retardant, neoprene expansion joint and an array of moulded parts which required hot vulcanisation at the joints. Vulcanisation is a difficult and time consuming joining process that requires a high level of skill and equipment to perform. As Incat did not have the in-house skills or equipment to complete this process, the supplier would send their own highly trained workers and expensive equipment to assist with every vessel they were building. This led to higher manufacturing costs, longer lead times and reduced control over the project. Incat approached Boss to develop a more efficient and economical solution.

The team at Boss presented a solution using an alternative material, welding technique and custom built machinery that is far simpler, easier, faster and less labour intensive to complete.

The alternative welding solution presented was hot-plate fusion welding. This welding process involves attaching the two parts to be fused on opposite plates of a specialised press tool. A hot plate, with a shape that matches the parts to be welded, is then positioned between them. The opposing plates are moved into contact with the hot plate and held against it until both surfaces soften and melt. Once this is achieved, the hot plate is removed and the surfaces are quickly pressed together and held under light pressure until the weld joint cools and re-solidifies.

This process is far simpler and faster to complete than hot vulcanisation and does not require the same level of skill or expensive equipment. To allow Incat to complete this welding procedure in-house, Boss designed and built a customised welding machine. This machine could be quickly, easily and safely operated to provide a permanent joint that is as strong as the parent material. The machines simplistic design allowed Incat to complete the entire installation in-house using their own labour, reducing installation time, waste and cost.

In order to adopt this improved welding technique, the material that was used to manufacture the expansion joint and moulded components needed to be changed. Previously, these components were manufactured using a flame-retardant Neoprene. Unfortunately this material is incapable of being hot plate fusion welded. The team at Boss decided that the best solution would be a customised Santoprene.

While Santoprene can be hot-plate fusion welded, it is not usually flame retardant. This was an issue, as one of Incat’s main specifications was for a flame retardant compound to be used. To develop a solution, Boss collaborated with a leading plastic and rubber compounding company. Together, a customised flame-retardant Santoprene was developed that was specifically designed for this application.

These modifications, coupled with the Boss designed machinery have allowed Incat to regain control of their manufacturing process. By using their own in-house labour, they were able to streamline the manufacturing process and dramatically increase production speeds, lower installation times and therefore increase profits.