Approaches
You can approach Cuttyhunk either from the east (Buzzards Bay) or from the west (Rhode Island Sound). In both cases you pass between Cuttyhunk Island and the smaller Penikese Island to the north. The ledges extend three quarters of a mile south and east from Penikese but they are clearly marked. There is a little more junk to avoid in the western approach, specifically Whale Rock and Pease Ledge.
If you're arriving from the south (Vineyard Sound), Quicks Hole is the simplest route through the Elizabeth Islands. Canapitsit Channel - narrow, twisty and ambiguously marked - is right next to Cuttyhunk but used mostly by shoal draft boats with local knowledge.
The entrance to Cuttyhunk Pond is a dredged channel between breakwaters. In 2010 and again in 2011 we found a controlling depth of 10 feet at an average low tide. A can marks the southern breakwater, which is frequently awash. The northern breakwater, with its prominent 29 foot tall light, is a more certain guide to the channel. Sand accumulates along the breakwaters unevenly between dredgings, so watch the sides of the channel carefully. If there are low sloping shoals visible above water, assume they extend underwater as well and give them a little extra room.
Once inside the Pond, remember that the mooring area is a dredged-out square prone to shoaling at the edges. There is a little channel marked with locally maintained buoys along the east side of the Pond; its depth is ambiguous on the chart but it's frequently used. In general, straying much beyond the moorings and the main channel to the docks will land you in shallow water fast.
Anchorages
In fair weather it is possible to anchor in the outer harbor between Cuttyhunk and Nashawena Island to the east, and boats often do so, but it is mostly exposed from northwest to northeast.
There is room for a handful of boats to anchor inside the Pond, at the northern edge of the mooring area. It's tight and the holding is reported to be poor, but most summer nights you'll reliably see a few boats anchored there, even when plenty of the moorings are still available.
Moorings
The town maintains 40 or 50 moorings for visitors inside the Pond. The moorings are first-come first-served, and generally fill up on summer weekends, although the Pond's flat calm waters do make rafting practical.
The moorings represent an important source of revenue for the town, up to a quarter of the annual budget {BG 9.2.02}. Pick up an empty mooring when you arrive and the harbormasters will come around to collect the fee.
Two private companies, Frog Pond Marine and Jenkins, maintain transient moorings in the outer harbor during the high season. At least one member reports an uncharted rock or shoal in the mooring field south and east of the breakwaters. Avoid the spot where the moorings look like a mouth missing a tooth.
Slips
The slips at the Town Wharf are primarily in shallow water, but it's not as dire for keelboats as the chart suggests. We've seen good-sized sailboats tied up at the end of the fingers, and the outer slips have 8 or 7 or 6 feet. For the most part, though, boats with a keel stay on a mooring.
Contact the Harbormaster before tying up at the Wharf.