Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: On Friday, shares of dry-bulk shipper DryShips (Nasdaq: DRYS) got torpedoed and sank to the sea bottom. Today, they're doing their darnedest to sink through the sea bottom -- down another 20%.

So what: Depending on whom you ask, DryShips is suffering either from investor disdain of its mini-spinoff of a small stake in its drillship operation, or from fears that DryShips' earnings report (due out Aug. 17) will mimic those from rival shippers like Genco (NYSE: GNK) and Excel Maritime (NYSE: EXM) and disappoint. Either one. Or perhaps both.

Now what: As I told you last week, investors are right to worry. While on the surface, DryShips' stock looks cheap at less than 5 times earnings, long-term growth estimates for the stock still hover around 4%, and the company is still struggling to generate positive free cash flow (and failing.) That last point is particularly troubling in a world where companies, who cannot generate cash of their own, may be forced to pay higher interest rates to borrow it from somebody else. Long story short, DryShips looks less seaworthy today than it did on Friday, and investors are right to avoid it.

Think DryShips is still ship-shape? Double-check your assumptions. Add DryShips to your Fool Watchlist, and see what's really going on.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.