It's been terribly difficult year-and-a-half for the world's largest offshore drilling contractor, Transocean (NYSE: RIG), and, unfortunately, it's impossible to predict with any sort of accuracy when its mounting tribulations will be reversed.

On Tuesday, following the commencement of a public offering of 26 million new shares, the company's per-share price slid 9.4% to $41.43. As such, for the year, the company's common shares have tumbled by 40% thus far in 2011. In addition to the primary offering, the company's underwriters will have the option to purchase as much as an additional overallotment of 3.9 million shares. The shares will be sold at a public offering price of $40.50 each. Net proceeds to the Zug-based company, following underwriting discounts, likely offering expenses, and a Swiss Federal Issuance Stamp Tax will be about US$1,008 million.

Transocean expects to apply the proceeds from the offering to a partial refinancing of its recent financing of Aker Drilling ASA, which it originally paid for with its available cash and the assumption of Aker's outstanding debt. For instance, the proceeds will replace the approximately $1.7 billion to repurchase Transocean's 1.50% Series B Convertible Senior Notes, which would come due at the close of 2037.

Transocean operates a fleet of 135 modern mobile offshore drilling units. It also has two ultra-deepwater drillships and four high-specification jackups under construction. Aker, which had been pursued by Bermuda-based Seadrill (Nasdaq: SDRL), is the owner and operator of two of the world's largest and most modern semisubmersible drilling rigs and has a pair of ultra-deepwater drillships under construction in Daewoo, South Korea. 

As you know well, Transocean was the owner of the Deepwater Horizon rig, which was completing a deepwater Gulf of Mexico well for BP (NYSE: BP) on April 20, 2010, when the rig exploded, burned, and sank, killing 11 of the hands aboard and resulting in the largest oil spill in U.S. history. With the after-effects of the tragedy appearing to have abated somewhat, BP, Transocean, and cementing contractor Halliburton (NYSE: HAL) have just been notified by the obviously relentless Obama administration that they face additional citations, probably within the next two weeks, for alleged safety and environmental violations dating back to the tragedy.

Nevertheless, Transocean continues to experience difficulties. Last week, one of its offshore drilling units, which was working offshore Newfoundland for Husky Energy, was struck by a supply ship. Apparently the rig suffered some damage, although there were no reports of injuries or pollution.

Given its still unsettled circumstances, especially as they relate to potential additional charges by the U.S. government and its unsteadiness in the market, I'm inclined to simply watch Transocean until a more definitive upward direction is established for the stock. Easily the optimal way to keep up with the rapidly changing company is to add its name to your version of The Motley Fool's free and personal My Watchlist.