The Eastern Pacific - Pacific Crossing Notes: A Sailor's Guide to the Coconut Milk Run - page 260

Running the Passes
In pre-GPS days, sailors avoided the Tuamotus for fear that the slightest navigational error
might put them high and dry on a reef. Nowadays, navigation to and among the atolls is
generally straightforward. The first real challenge cruisers face is entering an atoll. Happily,
the main passes into both Rangiroa and Fakarava are not only clearly marked, but ex-
tremely deep and wide as well. However, timing is everything! Throughout the atolls, you
must plan your entry (and exit) carefully and use the prevailing southeasterly winds to your
advantage. Avoid strong contrary tides (peaking at five knots or more in some passes) as
well as strong wind-against-tide situations. The best time to enter a pass is at slack tide,
even if that means waiting. After all, sailing is a game of patience. Of course, there are a
few exceptions to this rule of thumb. For example, passes located on the leeward side of an
atoll may be cautiously attempted at the tail end of an outgoing tide (in other words, against
the wind and a weak tide). Conversely, windward passes may be transited with a weak in-
coming tide. Unfortunately, the tide tables incorporated into some chart plotting programs
are inaccurate for this region, giving many sailors a nasty surprise. We used the French
SHOM tide tables instead and found these to be extremely reliable (see Fact File: Weather
and Tide Resources for the Tuamotus ) .
Another factor to take into account when entering a pass is the sea state. Because the south-
ern and western sides of the atolls are usually very low, seas will break over the reefs after
a period of strong, sustained winds from a southerly or westerly direction, or if a southerly
swell of more than six feet has been running for some days. All the water pushed into the
lagoon this way will flood out through the atoll's passes, causing an enhanced outgoing and
a weakened incoming tidal stream. This effect will also delay (or even eliminate) the low
water slack tide while advancing the high water slack tide by an hour or two. Ultimately,
you should calculate the window of opportunity as best you can, then carefully observe
pass conditions upon approaching. If in doubt, use VHF channel 16 to contact boats
anchored inside the lagoon or to reach a local dive operator for local advice. Don't be put
off by a bit of uncertainty - the atolls will repay your patience many times over.
At oft-traveled passes like those in Rangiroa and Fakarava, there is absolutely no need to
send someone aloft to eyeball the route ahead. We saw one sloop crashing its way into
Fakarava's north pass in a wind-against-tide situation with one crew member perched up in
the spreaders for “safety.” How the poor man kept from being launched overboard as the
sloop pitched and slammed wildly was a mystery. It's far better to wait for a favorable tide