For submarine cables, the next decade will be defined by new technological developments that will significantly alter the industry. Advances in transmission technology, artificial intelligence, virtualization and new materials will change the way cables are operated and maintained.

But technological changes also will impact the cable planning process. The technology we will focus on today is autonomy – specifically the use of autonomous surface vessels (ASVs) to conduct marine surveys for cable routes.

The markets for both offshore wind cable and submarine fiber optic cable are booming worldwide. Demand for offshore wind cable set a record in 2018, while subsea fiber demand was at its highest in nearly 20 years. The result is that thousands of kilometers of new cable routes need to be surveyed every year. Most of the surveys will be conducted in the traditional way, using a manned survey ship. This can be an expensive operation and with so many cable routes to be surveyed, coupled with the ever-present need to reduce costs, innovators are looking at ASVs as an alternative in some cases.

In November, SubCableWorld was at the Blue Innovation Symposium, organized by Salve Regina University and sponsored by the Consulate General of Canada in Boston and held in Newport, Rhode Island. The Blue Innovation Symposium is the premier event in New England (a technological center for the development of autonomous vehicles) for connecting the marine technology industry for education, networking and facilitating partnering opportunities.

This event covered a wide range of ocean technologies, but it was particularly strong in the sphere of autonomous vehicles for ocean applications. While using ASVs to conduct marine surveys for cable routes was not a specific topic, SubCableWorld spoke to a number of people at the event about their potential.

In this article, we will focus on SeaTrac Systems, Inc., one of the companies that presented at the Blue Innovation Symposium. SeaTrac’s ASV struck our eye as it has solar panels to recharge its batteries, thus giving the ASV a much longer operational endurance.

ST 2 HULL LOGO HIGH RES CROPED

SeaTrac, located in Marblehead, Massachusetts, has built and tested its prototype ASV, known as ST-1. This 14’ boat is capable of producing up to 600 watts of power thanks to the solar panels to recharge its 4.3 kWh battery. This gives the ST-1 an endurance that can be measured in months.

The ST-1 has been thoroughly tested. In 2018, the vessel conducted six live missions for organizations ranging from Woods Hole Oceanographic Institution (WHOI) to Teledyne to the Navy Seals.

“In June, for example, we monitored eelgrass health and water quality for Massachusetts Bays Estuaries and the Massachusetts Division of Fisheries in a tricky body of water, the three mile wide embayment in and around Duxbury/Plymouth/Kingston Bay, which is subject to large tidal swings that render much of it mudflats at low tide. The scientists were attracted to the SeaTrac vessel for its ability to take continuous samples (temperature, salinity, turbidity, dissolved oxygen and chlorophyll), as it traversed a 20 mile course, carefully timed with the tides. The SeaTrac development platform performed well in both near shore and open water despite considerable chop, and had plenty of power to run the sensor affixed to its belly, a YSI sonde. The scientists were pleased enough to repeat the exercise in August and are presently planning a similar mission for Boston’s North Shore,” said SeaTrac Communications Director Alessandra Bianchi.

By entry to bay

Now the company is preparing to debut its production-model ASV, the ST-2. At 15.75 feet, it is an enlarged and more powerful version of the ST-1, with more speed (4.5 knots), solar panel power (750 W), battery capacity (6.75 kWh), motor power (500 W), payload capacity (50 kilos), and easier launch and recovery.

The ST-2 is designed to serve a wide of applications that are often filled by ASVs – security, defense, offshore O&G, etc. – but also is well suited for cable surveys.

“Given the nature of subsea cable routes, they have near shore, shallow and deep water survey requirements. We have specifically designed our boats to accommodate any depth of water from one meter out to open ocean. We feel that our ASV could be a useful vehicle to assist in this job. We don’t require wind or wave propulsion. We can station keep and go upwind. We have power burst features and we really intend for the boat to be a utility vehicle in a variety of bodies of water,” said Bianchi.

Its engineers liken their vessel to “a pickup truck for the ocean,” and, based on some industry feedback, are presently working on adding some additional topside cargo carrying capacity, to serve as a mobile tool box on water.

“We’ve tested the prototype and sent it into the field to find out what works and what doesn’t. We’re excited about the improvements we’ve made to the ST-2,” added Bianchi.

comparison

The ST-2 can mount a wide variety of equipment -- magnetometers, multi-beam sonar, echo-sounder, side scan sonar, sub-bottom profiler, etc. SeaTrac believes that the ST-2’s available battery storage and solar power collection together can support most of the sensors used for cable survey and inspection.

“We have a variety of ways to launch and retrieve our vessels. All come standard with a dolly, a trailer, and a center lift, so we can launch from a crane, a boat ramp, or from a ship. We plan to sell as well as rent our vessels. We think this is an advantage for survey companies that need a short-term solution for a cable survey requirement,” said Bianchi.

“We believe that our ASVs can be a cost-effective tool to assist operators with cable survey and inspection projects,” said Bianchi. “While we’re in startup mode, we are also looking for collaboration partners to find out.”