Tisbury official says waves hit transformers

Questions linger about stray voltage in Vineyard Haven Harbor.

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A grid cooler from the MV Island Home damaged from electrolysis. —Courtesy Steamship Authority

Tisbury building inspector Ken Barwick contradicted the notion a truck damaged one of two pads supporting transformers at the Steamship Authority Terminal in Vineyard Haven so severely it needed to be bound in chains — a scenario the Steamship Authority maintains.

Barwick told The Times the damage was the result of wave action from a storm. He further said a concrete-backed steel bulkhead installed by Robert B. Our last year in front of the transformers was, among other things, meant to blunt future waves. Barwick said he recently went on a lengthy tour of the terminal and described the chains as necessary to keep the transformer above them from falling off. Repairs to the pads originally anticipated to be done last autumn are now expected to happen this summer.  

On Monday, SSA spokesman Sean Driscoll disputed Barwick’s account. “Our response is that it was a truck,” he wrote in an email.

When asked about the transformers and pads in August, Tisbury electrical inspector Ray Gosselin deferred to state inspectors because the Steamship Authority is a quasi state agency. A state building inspector did inspect the pads in August and deemed the chain wraps on the most decayed of the two acceptable until a structural engineer could perform an inspection. An inspection by a structural engineer never occurred, because, according to Steamship Authority spokesman Sean Driscoll, the ferry line was satisfied with an examination by Eversource, in addition to the state building inspector, and opted to wait until a Boston architecture firm develops a bid package and then to wait for a successful bidder to begin work.

It’s unclear if the damage caused to the pads extends to the wiring beneath them. Eversource spokesman Reid Lamberty said on Monday the utility owns the incoming cable but not what extends from it. “The primary cable that goes from the street to the transformers is ours and is in conduit,” he said. He said it was “unlikely” to be leaking electricity. However, he said the SSA owns the secondary lines that extend from the transformers to the ferry slips and terminal buildings. He did not speculate on their condition. He previously stated Eversource had inspected the damaged pads and found them to be safe.

Late last spring, members of the Tisbury Harbor Management Committee discussed their belief stray electrical current was at work in Vineyard Haven Harbor due to, among other things, the rapid decay rate sacrificial anodes or zincs in its waters. Marine anodes are meant counteract waterborne current so it doesn’t affect metallic boat components.

“Any time you have two different metals that are physically or electrically connected and immersed in seawater, they become a battery. Some amount of current flows between the two metals,” the Boat US website states. “The electrons that make up that current are supplied by one of the metals giving up bits of itself — in the form of metal ions — to the seawater. This is called galvanic corrosion and, left unchecked, it quickly destroys underwater metals. The most common casualty of galvanic corrosion is a bronze or aluminum propeller on a stainless steel shaft, but metal struts, rudders, rudder fittings, outboards, and stern drives are also at risk. The way we counteract galvanic corrosion is to add a third metal into the circuit, one that is quicker than the other two to give up its electrons. This piece of metal is called a sacrificial anode, and most often it is zinc. In fact, most boaters refer to sacrificial anodes simply as zincs.”

As industrial electrician Cole Powers previously told The Times during his investigation and mitigation of stray voltage in Menemsha Harbor, boats with poor or incorrect wiring can send voltage into the water. Powers said at the time, declaring a harbor like Menemsha current-free is risky because there are so many hidden avenues for electricity to find its way into the water. For instance, he said electricity can migrate from live wires to old dead ones left in the earth. And tests on a live wire might not indicate anything amiss even though it could be channeling current to a dead wire.

After The Times inquired about wires snaking to nowhere under water by the dinghy dock alongside the Vineyard Haven terminal, those wires vanished and SSA general manager Robert Davis said they were dead and useless and were removed. He subsequently dispatched a diver to inspect marine wiring at the terminal. The diver found “no faults,” Davis said.

Tisbury decided to mount an investigation of potential current in Vineyard Haven Harbor last June, but as of February, no testing seems to have occurred, according to DPW director Ray Tattersall and harbormaster John Crocker. Both said Powers was to be tapped for the work but were unsure if he’d been secured. Powers could not be immediately reached for comment.

Gosselin told The Times Friday he was never informed local mariners, including Harbor advisory Committee chairman Jerry Goodale, have expressed concerns about accelerated rates of electrolysis in the harbor.

The 4,000 volt transformers along the harbor at the SSA terminal provide shore power to ferries and power the terminal. The largest vessel in the SSA fleet, the 255-foot MV Island Home routinely visits the Vineyard Haven terminal. Last April the Island Home returned to service after overhaul work at Senesco Marine where new diesel bow thrusters were installed to replace the original electric ones. By autumn, electrolysis had consumed the sacrificial anodes installed in the bow thrusters and damaged a grid cooler, a major bow thruster component. The Fernstrum anodes are typically replaced every two years, according to Driscoll. The grid cooler required stopgap repairs at Thames Shipyard while the SSA shopped for a new grid cooler. The Island Home is currently undergoing annual maintenance at the SSA’s Fairhaven facility where the new grid cooler is being installed. It’s expected to return to service March 24.

The possibility of current in the water poses more than a threat to boats and marine infrastructure. Marine current hurts and sometimes drowns swimmers with regularity, according to the Electric Shock Drowning Prevention Association. There has been no evidence to suggest swimmers have encountered stray current in Tisbury waters. However several did in Chilmark when that harbor was haunted by elusive voltage. One child from the West Tisbury School received a strong shock during a school trip to Menemsha in June of 2017, precipitating a lengthy investigation of harbor electrical infrastructure.