Two companies that helped renovate a troubled Johns Island marina are suing the project's financier, alleging it knew the development was running out of money but allowed them to continue working on it.

Crest Industries and Dock & Marine Inc. say they are owed a total of more than $870,000 in unpaid construction bills.

They are now seeking to collect from the National Bank of South Carolina, which lent the owners of St. Johns Yacht Harbor money to renovate the docks and build amenities, such as a pool and restaurant.

In December, the bank began foreclosure proceedings on the 225-slip Stono River marina, saying it was owed $25 million by owner Stono Marina Partners.

A handful of other companies also claimed the owner owed them money. In court documents, the two builders alleged that the NBSC loan was "on the cusp of default" around April 2009, but that the bank did not file a foreclosure lawsuit until nine months later.

Also, the lender sent representatives to respond to contractors' payment requests up until late October, even though it knew last summer that there wasn't enough money to finish the work, according to documents.

"It's clearly in the bank's interest to keep these guys working because every day they keep working, it increases the value of the bank's collateral," said attorney Ben Peeples, who represents Dock & Marine

NBSC attorney John Hagerty denied the allegations, adding that he's optimistic that the bank will prevail at a hearing scheduled to address the matter next week.

Dock & Marine says it is owed $428,862 for work done on St. Johns Yacht Harbor, where slip sales began to suffer as the real estate market tanked.

Crest Industries, a Johns Island builder, alleges it is owed $444,384 for work it completed on the clubhouse.

A hearing in the case is scheduled for Tuesday. Peeples said a trial also could begin as early as next week.

Reach Katy Stech at 937-5549 or kstech@postandcourier.com.