SHADOWCAT Q&A With SEAmagine Hydrospace About Submersibles

As the submarine provider for SHADOWCAT’s award-winning Hodor support yacht, SEAmagine Hydrospace Corporation offers many submersible models ranging in size. Read a Q&A below with Charles Kohnen (CK), president, to learn more about incorporating submersibles aboard SHADOWCAT support yachts.

Please provide a brief overview of your company and why your submersibles are well suited for SHADOWCATs.

CK: SEAmagine Hydrospace Corporation is an industry pioneer established since 1995 and with more than 12,000 dives on its submersibles. The company fabricates two- to seven-person submersibles, with a depth rating ranging from 50m to 2300m.

We build personal submersibles for adventurous yacht owners who want to share their enthusiasm for exploring the wonders of the underwater world with family and friends. Our personalized vessels are fabricated with the latest technology and comfortable, spacious interiors designed to be a seamless, carefree, and accessible extension of the family yacht experience.

We guarantee to always focus on safety, reliability, environmental stewardship and industry-leading training. We provide all our clients solid long-term international support to help captains and crews provide yacht owners truly unique adventures beneath the sea.

Photo: SEAmagine’s submersible aboard SHADOWCAT’s *Hodor* support yacht (Photo: SEAmagine)

Please provide a brief description of the sub built and deployed on SHADOWCAT’s Hodor.

CK: SEAmagine delivered a three-person, 1,000m depth rated Aurora Submersible to SHADOWCAT Hodor. The submersible’s main hull is a large spherical window that is over 2m in diameter, behind which the occupants sit comfortably. The focus is maximizing the passengers’ true field of views obtained from inside the large window, ensuring a comfortable and spacious seating interior, providing a unique and easy boarding configuration for people of all ages, and giving the vessel unmatched maneuvering agilities that allow up close viewing of the underwater scenery and its sea life.

This submersible was configured with a four-point hoist arrangement though a single point hoist configuration is an option for this vehicle when requested.

Are there any size limits for subs that would be housed and operated from a SHADOWCAT? Is there a standard or preferred size?

CK: SHADOWCATs are very accommodating to hold submersibles of various sizes and weights. Often, yachts have limited space or do not have the ability to launch heavy loads such as submersibles. The preferred weight of submersibles for a SHADOWCAT is to remain under 10 tons to make the launch and recovery more manageable though heavier loads can be accommodated with proper study.

Are there any specific design specifications for subs being deployed from SHADOWCATs? Perhaps structural additions that would allow for lowering and lifting?

CK: Submersibles are heavy for their relatively small size and the prime consideration for integration onto a SHADOWCAT is the launch and recovery arrangement. There are two main specifications that determine the size and weight of a submersible. That is, the number of occupants the vehicle is to hold and the maximum depth rating. The deeper rated and more occupants it can hold, the heavier the sub becomes.

SHADOWATs can be equipped with knuckle-boom cranes or with side-launch overhead beam cranes, depending on the size and weight of the submersible. SEAmagine often semi-customizes the hoist points on the submersibles to best integrate with the ship’s specific launch and recovery system. SEAmagine subs can be fitted with single-point, three-point, or four-point hoist arrangements.

Is there an advantage for a super yacht owner to consult with you and SHADOWCAT during the planning, design and construction phase?

CK: Submarines are best integrated on board a superyacht during a new build’s study and we recommend owners do so early during the engineering phase. SEAmagine often makes customizations on its submersibles to better integrate on a given yacht. These accommodations involve either reducing the weight of the submersible, accommodating final dimensions slightly to better fit, or changing hoist-point configurations to meet specific launch and recovery systems.

The most important point that owners with an existing yacht need to know is that, if they are curious to know if a submarine could be fitted on board their ship, they need to contact us and discuss the options as opposed to simply assume that it is not possible. The shipyards will not know what accommodations we can make on the sub to make the integration simpler. At SEAmagine, we have highly experienced engineers who have been doing this for over 25 years who can work hand-in-hand with captains, shipyards and designers to find the best approach.

A SEAmagine submersible stored in SHADOWCAT’s submarine bay (Photo: SEAmagine)

How would you describe the sub bay on a SHADOWCAT?

CK: The sub bay aboard the SHADOWCAT is ideal for submersibles. It offers a very high ceiling, allowing the crew to easily enter and exit the vehicle from the to hatch. The bay has good storage space for holding spares and has sufficient space to integrate the submersible’s battery chargers. The sub bay also provides sufficient space for the crew to access all side of the vehicle.

The sub sits on an air skid that allows the crew to readily move the vehicle in and out of the sub bay. For more spacious access around the sub during maintenance, the vehicle is simply moved out of the sub bay to the main deck area underneath the host beams.

How many personnel are required to maintain, operate, launch and retrieve submersibles on SHADOWCATs?

CK: SEAmagine provides its submersible pilot and topside crew training program with each vehicle that it delivers. SEAmagine’s training program was initially developed with the U.S. Coast Guard in the late 1990s and has been a standard ever since. A submersible operation is performed with a minimum of two trained personnel. One is a trained Submersible Pilot and the other is the trained Topside Controller with “control tower” responsibilities at surface. SEAmagine does provide a basic training for all deckhands that will assist the operation including launch and recovery and during dive operations. During launch and retrieval operation the SHADOWCAT requires the pilot to be assisted by five crew members to efficiently perform the operation.

During submersible’s diving operation a tender follows the submersible and remains approximately within a 500m radius of the sub while the crew tracks the sub’s position and communicates with the pilot. This support tender will have a driver and the topside controller while the pilot will be underwater in the sub with the passengers.

What other support vessels and/or equipment are needed to support submersible operations?

CK: As mentioned above, our subs require a support tender during operations. This support tender should have a 120+hp engine to ensure that it can, if needed, tow the submersible.

The submersibles have numerous backup systems in case of emergency to always bring them quickly back to surface. Furthermore, the submersibles have the capacity to stay four days under water. If the submersible is diving within SCUBA diving depth, then divers can readily assist the vehicle. For greater depth the sub may need assistance from an ROV if it gets snagged in a fishing net or seafloor cables. In such instance either the ship calls a third-party ROV service provider or it can hold its own ROV system onboard. The SHADOWCAT design is very well arranged to hold its own ROV system – the bow area is ideally suited to hold an ROV that can used to assist the submersible if ever needed.

The submersible does use pure oxygen bottles for its life support system. These oxygen bottles provide approximately 40 to 60 hours, after which they need to be refilled. Often on yachts it is simpler to keep a few spare oxygen bottles in storage and they get refilled when the ship back at the shore. For long expeditions that are in very remote locations then an oxygen generator can be installed on the SHADOWCAT and allow it to never run out of oxygen during an expedition.

How can superyacht owners ensure the best possible underwater experience for themselves and their guests?

CK: SEAmagine is a full-service provider in both training and technical support once it delivers its subs on to a yacht. Each of SEAmagine submersibles are fully classed by the American Bureau of Shipping (ABS) and also on Cayman Flagged ship’s registered with the Cayman Shipping Registry. SEAmagine supports the yacht captain and its crew in handling the annual surveys required by the ABS Class Society and by the Flag State. At the same time, SEAmagine engineers perform at least annually a full preventive-maintenance schedule to ensure the submersibles are in their best form at all times.

Often, SEAmagine assists owners in procuring special permits for certain dive locations that are protected and need diving approval from the location’s supervising organization.

SEAmagine often is requested to add more peripheral equipment on a submersible as the owner’s expeditions vary. For example we have add more HD cameras, deep water rated 360 camera system, new robotic manipulators to take samples from the seafloor, and so on all depending on the objectives of a planned expedition.

To learn more about integrating submersible technology aboard a shadow yacht, contact the experts at SHADOWCAT.

Q&A with SEAmagine Hydrospace Corporation