Have you ever heard project managers talk like this?
We decided to take a different tack with the rollout project, after we ran afoul of the ordering processes. Julie was swamped with acquisitions paperwork and helping Sam learn the ropes, so we deep-sixed the new hardware. Office scuttlebutt is that the boss wants to cut expenditures so it's easier to go with the flow on that one. The OS upgrade project had a minor hitch, but that project is on deck now -- all we have to do is tie up the loose ends and it'll be all sewn up. That will put us on an even keel for the rollout and if nobody rocks the boat the support team will stick with us until the bitter end.
Although this is fictional I've heard all these colloquialisms in the office, and probably only recognize them as nautical because of an interest in etymology and a couple years of sailing. A non-sailor or person for whom English wasn't their native language might have a hard time seeing where these come from (and thus, how to use them properly). Herewith, a guide.
To take a different tack is a change in direction while sailing. Tacking itself means to progress by changing directions frequently, like zigzagging. This is necessary to make progress into the wind: a boat can sail quite fast when it's pointed nearly into the wind, but it can't make progress directly into the wind. Thus the boat zigzags so that the wind comes over the port side first, then starboard, then port. Don't replace with the word "tact" as Michael Rubin did.
To run afoul is to hit a snag, a complication, particularly in laws, regulations, contracts or processes. On a sailing boat a fouled rope is one which is caught up in another rope or another piece of equipment. Fouled ropes can cause quite a tangle if sailors keep doing what they're doing.
Swamped is quite suggestive, as a swamped boat is literally filled with too much water. A swamped boat is not only heavier but also sits lower in the water and presents much more drag on the water, so no wonder a swamped boat moves so slowly.
Learning the ropes is exactly what a sailor does on a new ship. Sailing ships have very individualistic rigging, often the result of years of modifications and jury rigs.
Deep sixing is burying something in six fathoms of water (a fathom is six feet), deep enough for it to be gone.
Scuttlebutt was the term for ship-board gossip. A butt is a cask of a certain size. A scuttle is a small hatch on deck. Thus, the scuttlebutt is a butt lashed onto the deck near the scuttle. Often this butt contained fresh drinking water. How a propos that today this might also be called "water cooler talk".
Go with the flow is simple -- it can apply to the flow of a river but also to the tides. Leaving harbour when the flow (the tide) leaves is much easier than going against the tide.
Hitch is a specific kind of knot tied in the middle of a rope. When winching a rope, winding it or running it through a cleat, a hitch would temporarily stop progress. However, it's not as bad as a fouled line.
On deck meant something physically on the deck of the boat, the exterior top surface where people stand. This probably migrated first to baseball where the batter going next is said to be on deck.
Tying up the loose ends meant to literally clean up the long ends of lines (ropes) hanging off a rigging once it was rigged. Loose ends were dangerous on ship, causing fouled lines and getting in the way of sailors moving around. Naturally this was always the last step in rigging, part of doing the job well.
All sewn up probably refers to the shroud around a corpse prepared for burial at sea. A corpse ought to be weighted down by something like a cannonball. The cleanest way of doing this was to put the cannonball and the corpse together in a piece of sturdy sailcloth and sew up the edges. After being sewn up there was nothing left to do before burial.
Even keel is a ship's position. The keel is the center bottom line of the boat from front to back. A ship with an uneven keel, dipping into the water more at either bow or stern, was probably badly loaded. An uneven keel meant that the ship wouldn't sail as efficiently because it would not present an optimal profile for water resistance. More generally it simply means going smoothly, steadily, without waves rocking the boat.
Rock the boat is too simple to need much explanation...
Bitter end is a very specific end of a line (rope) -- the end that goes around the bitt, a kind of deck post. I guess sailors would be told to pull on or coil the rope until they reached the bitter end.
(Sources: take another tack, deep six, scuttlebutt, all sewn up; also other pages on same sites)