Approaches
The only reason to talk about Pollock Rip as part of a cruise is if you hope to include a trip around Cape Cod in your itinerary. If you do, it's important first of all to understand the commitment this implies.
Pollock Rip requires planning before your cruise for the significant currents. It requires flexibility in your schedule to accommodate the weather. And it requires effective reaction, while underway, to cross-channel set and changes in the contour of the shoals. Here's a look at each of these considerations:
Currents
The tidal currents flow through Pollock Rip at maximum velocities of 1.5 to 2.5 knots. That's a big chunk of headway for most cruising sailboats. Currents are strongest right around the south tip of Monomoy, but they continue at appreciable velocities for 6 or 7 miles into Nantucket Sound, and for a similar distance up the east side of the Cape. So while it's possible in flat weather to power a sailboat through against a foul current, it's pretty slow.
Most sailors time their passage to the fair current, saving a couple hours of transit time. Avoiding the head currents does mean that Pollock Rip is effectively "closed" for 4-hour periods twice a day in each direction. Since it's almost twenty miles (i.e. half a day) from Monomoy to either Nantucket, Chatham or Hyannis, coordinating your harbor arrival or departure time with the Pollock Rip currents has to be the starting point for planning this part of your cruise. The 12 pages of current charts in Eldridge give an hour by hour graphical representation of the full tide cycle in Nantucket Sound. Or NOAA has a tabulated schedule of currents in Pollock Rip online here.
In Butler Hole the current runs across the channel enough to push you out if you fail to correct for it. The first challenge is to recognize how much you're being set, and there are few visual clues. The shoreline is nearly featureless, with no landmarks ahead or behind, and the buoys can be more than a mile apart. It's important to take frequent bearings on the buoys both ahead and astern, as well as to closely watch Course Over Ground on the GPS. Most first-time navigators through Pollock Rip will significantly underestimate the cross-channel set, and will fail to compensate adequately.
Slack water is not a precisely synchronized and tabulated event here. I can remember heading up the west side of Handkerchief Shoal, just after "slack water," thinking the new west-going current would push us safely into Nantucket Sound. Busy with a sail change, we failed to notice that in spite of what the book said, the current for us was still running east, pushing us back over the Shoal. Some single digits on the depth sounder got our attention.
Weather
The most important weather consideration is finding a 24 hour window of fair conditions to get around the Cape to your next harbor. It's much easier to find this window if your schedule allows you to make the passage a day earlier, or later, in your cruise.
Avoid going through Pollock Rip when the wind and current oppose each other - for instance riding a west-going current from the ocean side into an afternoon southwest breeze. The resulting chop can be wet and uncomfortable for a dozen miles.
Shifting Depths
With its exposure to ocean storms, the sands of Pollock Rip are constantly in motion, so any chart is guaranteed to be inaccurate somewhere. Sailing directions from the 1850s describe a shoal that "partly dries at low water" {Norie p94} where today's charts show minimum depths of 7 feet. Our depth sounder in 2007 gave readings well over 100 feet where the chart showed 50 or 60 feet at most. At the same time, we could see breaking water extending from a marked shoal, past the buoy and part-way across the channel.
The deep water through Butler Hole is well-buoyed and frequently used by fishermen; it should be safe to start with the marked channel. But simply following pre-printed courses or old waypoints can get you into trouble here. Expect buoys to be in new positions. Decisively favor the upwind, up-current side of the channel. Don't be surprised if the depth sounder and chart disagree; trust the depth sounder and alter your course towards deeper water when it's appropriate. And carefully watch the surface of the water for evidence of current set and shallow spots.