Bouchard Transportation has added three more insurance companies as defendants in its $21.5m lawsuit concerning a 2017 explosion aboard an articulated tug barge that killed two crewmembers.

The Morton Bouchard III-led company is pursuing XL Catlin Lloyd's Syndicate of London and US-based insurers XL Specialty Insurance and Navigators Insurance, according to papers filed in US District Court for the Southern District of New York.

In October, the privately held tug and barge owner filed the suit initially against Travelers Property Casualty of America and Atlantic Maritime Associates (AMA), a maritime surveyor acting as Travelers' expert witness.

Bouchard brought the suit against Travelers in September 2018 for allegedly not paying for repairs to and total loss of 9,800-gt B No 255 (built 1999).

The 468-foot ATB was part of an articulated tug-barge unit with the 127-foot, 6,140-bhp Buster Bouchard (built 1979).

In June 2017, Bouchard entered into a marine contract with Travelers for hull and machinery (H&M) insurance on both the tug and barge, court papers state.

The hull policy provides Bouchard with marine insurance coverage for the losses alleged in the suit.

Calls to Bouchard's attorney Lyons & Flood and the case's three latest defendants, referred to as "H&M defendants", were not immediately returned.

On 20 October 2017, the tug and barge were in transit from Saint James, Louisiana, to Corpus Christi, Texas, carrying 133,000 barrels of crude.

At 4:30 am, while the vessel was about three miles off Port Aransas, Texas, an explosion and fire erupted in the barge's peak foretank, resulting in heavy damage to the barge and the deaths of two crew members.

Court documents state that Signet Marine provided salvage operations at sea and at port and moved it five days later to Gulf Copper & Manufacturing Corp repair yard in Port Aransas.

The barge underwent temporary repairs at the yard and was then moved to Mississippi's VT Halter Marine Yard in early March before being sent to Universal Environmental Solutions (UES) in Tampa, Florida, for permanent repairs.

Travelers paid for some of the $3.4m in repair invoices from these service providers but declined to reimburse Bouchard for about $3.5m in expenses, plus interest, court papers say.

In the latest lawsuit, Bouchard claims that Travelers, AMA and the H&M defendants also failed to pay Bouchard another $18m for the agreed value of the destroyed barge per the hull policy.

Bouchard also alleges that the five defendants interfered with contracts between Bouchard and hired repair services by refusing to pay Bouchard for "excessive or substandard" repairs.

Bouchard also alleges that they also tried to change the barge's agreed value by asking its broker to submit a new valuation, according to court documents.

Because of delays in reimbursements for the hull damages, Bouchard scrapped the barge to "cut its losses."