South San Francisco Bay Charter's Handbook - Bay Conditions

San Francisco Bay Conditionsbehind Angel Island and Tiburon. The wind in
The sailing conditions on San Francisco vary byonearea can be 30 to 35 knots while a few
time of year,time of day and even by exacthundred yard away itmight be only 10 knots.
location. The windy seasonbegins by mid springKnowing what lies ahead, smartsailors will find the
and lasts until September. In the fallthe sailing getseasiest places to hoist sails or reef.
mellower and mellower until, by winter-time,thereThere's more commercial traffic in The North Bay
are many days when there's hardly enough windincludingtug boats, ferries and ships. All of them
tomake sailing worthwhile. But there are a feware a lot faster thansmall sailboats. It can take as
good days inwinter, usually after storms havelong for a small boat to crossa shipping channel as
passed through the area.it takes a large ship to travel up totwo miles.
The spring and summer is the windy when weKeep a constant look out for all commercial
get smallcraft advisories almost every afternoon.trafficand especially the ships which can not
The wind peaks midto late afternoon and locallydeviate from theirchannels. You need to start
tends to be a little stronger atthe San Mateomoving out of their path wellbefore they become
Bridge. The normal direction is from thenorthwestclose to you. Get a chart briefing fromany of the
but it tends to blow a little more from the westvarious members of the Spinnaker staff who
asit gets stronger in the afternoon.arefamiliar with North Bay commercial traffic
There are some spots that routinely get strongerpatterns beforeheading there for the first time.
wind. Rightthrough the Golden Gate towardsFog can be an additional factor in the North Bay.
Berkeley, it's called theSometimesthe bottom of the fog layer is far
"slot" because so much wind is forced through theenough above the water thatyou can see traffic
areabetween San Francisco and Marin County.on the bay but sometimes it comes rightdown to
There are otherareas known for strong wind. Thethe deck. When this happens,
San Bruno Gap blowsthrough the area nearextraordinarymeasures must be taken to
Oyster Point Marina and The Crystalavoidcolliding with other vessels or obstacles. The
Springs Gap focuses wind from about Coyotefog tends tolimit itself to the area from the
Point to theGolden Gate to the Berkeleyside of The Bay
San Mateo Bridge. It's important to note thatbetween Richmond and Emeryville. It alsotends to
where there isstrong wind blowing over a greaterbe heavier in the west. Transiting this area
distance of water, therewill be larger waves. Thiswhenthe fog is on the deck is extremely
is called "fetch". For a given windstrength, thedangerous and shouldbe avoided if at all possible.
longer the fetch, the larger the waves.If you're stuck in the fog have tomove, try to
Boats usually don't have to travel far in Sanstay completely out of shipping lanes or if you
Francisco Bay tofind shelter from the wind anddohave to cross one, do so at right angles and
the waves. On the south sideof the "slot" there'swith extremecaution. If you have VHF radio, you
some shelter behind Treasure Islandand directlycan listen to channel 14to learn what the
behind The City. On the north side there'ssheltercommercial shipping traffic is doing.