The last five years or so we've taken a 48 ft. mono with 5'5" draft into the mooring field at Anegada.
It's tight, but we have never had a problem. Enter slow, with an escape plan firmly in mind and your claw on the throttle ready to take action! If the only balls free are the ones close in to the shore or right at the back of the field then forget it...those are too shallow.
Also remember that the BVI has tides...The Moorings website states the range as 12 - 18 inches. Tide Forecast says up to 2 feet...which sounds on the high side compared to our observations so I assume that must be the maximum high water spring to minimum low water spring difference. And factor in swell. We always snorkel our position once moored to ensure there is enough daylight under the keel.
Tip 1.) If a decent swell is running then we don't attempt Anegada. www.WINDGURU.CZ/58
has been a reliable source of swell prediction for us.
Tip 2.) don't do the long, slow loop around the mooring field to approach the ball perfectly into wind from a few hundred meters away (like you would anywhere else), head direct to within a boat length or two of the ball and use that bow-thruster to complete the hand-brake turn!
Tip 3.) when you do your boat briefing / handover, check if there is an offset on the echo-sounder. Our first year someone had put 4ft beneath the keel 'to be safe'...so it helpfully read zero all the way in, which is bugger-all use to anyone. We now ensure that it is calibrated correctly, without any offset.
Tip 4.) Good pair of polarised sunglasses.
Tip 5.) don't be put off Anegada. Most of the BVI is incredibly simple navigation compared to the rest of the world...Anegada is just slightly less so. In the right weather you will be absolutely fine with 5'5". And that first painkiller after snagging a ball tastes better than anywhere else in the BVI (if you're the skipper!).