A navy ship that helps Canada scan for mines on the sea floor has twice damaged high-tech underwater gear in accidents on the West Coast, racking up big repair bills, newly released documents show.

The incidents involving HMCS Whitehorse have prompted a reprimand and tighter controls over how the sophisticated technology is used. 

Damage to high-tech sonar devices towed by HMCS Whitehorse could cost $300,000 to repair.
(DND)

For more than a year, the ship's crew has been mapping the sea floor around Vancouver Island using side-scan sonar, a technology that involves towing a torpedo-shaped sensor behind the vessel.

But on Oct. 14 last year, the five-metre sensor — known as a towfish — smashed into an unexpected pinnacle of rock rising sharply from the sea floor. The navy could not provide the exact cost of repairs to date, but said it was between $50,000 and $100,000.

And on June 15 this year, the crew smashed a second towfish into a ridge of rock near the entrance to the Nanoose experimental test range, on the east coast of Vancouver Island.

Gyroscope damaged

The impact damaged a tail fin, a shaft and internal electronics, including a gyroscope. MacDonald, Dettwiler and Associates Ltd. is still repairing the device for the navy, but the bill is expected to be between $100,000 and $200,000.

With only four towfish available for work on the West Coast, the ship's crew now has smashed half the naval inventory.

Records released under the Access to Information Act show that investigators blamed carelessness on the part of the operators for the second incident, though absolved them for the first.

"This is by nature a fairly high-risk exercise," navy spokesman Lt.-Cmdr. Mark MacIntyre said in an interview from Victoria.

"We're finding things that frankly we didn't expect in terms of these seamounts or pinnacles … On two occasions, the towfish struck bottom."

Detailed maps required

The navy requires detailed baseline maps of the sea floor to be able to detect changes that might indicate the deposit of an enemy mine or other hostile device.

Current hydrographic charts are inadequate from a military perspective because they map in detail only potential hazards to shipping, that is, only to the depth of the largest hulls.

Deeper sea floor features are often missed or only roughly charted, and the Whitehorse crew — currently on another mapping mission — has to be constantly alert for sudden changes in deep-water topography.

MacIntyre said there have been no formal disciplinary measures taken against sailors, but in the second incident "the individual was spoken to and counselled on what happened."

"We've adjusted our standard operating procedures for route survey operations," MacIntyre added.

"We're being much more careful when our computer software indicates we have a steep slope."

with files from the Canadian Press