The Soviet Union has built its navy into a colossus but is using a "visibly wimpish" operational policy on the high seas that puzzles analysts, Jane's Fighting Ships says in its latest edition released Wednesday.

The new 1988-89 edition of the top reference book on the world's navies said Moscow's "impressive if not spectacular" construction program is now turning out one new nuclear-powered submarine every seven weeks."You have this colossal Soviet fleet and yet we seldom see them," the book's editor, Capt. Richard Sharpe, said at a news conference Tuesday.

And in his forward to the book, Sharpe wrote, "On the whole, the Soviet surface forces seem to prefer remaining snugly alongside in their home fleet areas rather than roaming the oceans of the world confronting the U.S. Navy."

Sharpe, a former British nuclear submarine commander, said the most popular explanation is the "bastion theory" - that the Soviets are using their navy simply for a defense of their flanks.

"This analysis of the visibly wimpish Soviet policy at sea can be overstated," Sharpe said. "But there is an enigma here which has not been convincingly explained.

"I don't think the Politburo trusts its navy and that's one reason why the ships are not out on the high seas," he said. "Possible defections and a lack of trust are very strong factors."