Friday, November 6, 2015

Weather Routing Options for Seattle to Victoria by Robert Reeder

Standard Route
Graphic 010)
2 hours 45 minutes 73 nm

This is our normal route between Seattle and Victoria. Through prior agreement with both country's
Vessel Traffic Services, we utilize the Vessel Traffic System lanes from Seattle to Port Townsend.
At the buoy "SA" precautionary area we depart the traffic lanes and transit directly to buoy "R" and
then buoy "VH," then from "VH" to Ogden Point and into the Inner Harbour.

On an ebb current with even moderate westerlies we will often see strong tidal dynamics at
Admiralty Inlet and a "washing machine" effect between Point Wilson and buoy "SA." At this time
there is not a weather buoy at this location.

An important consideration for transiting the eastern entrance of the Strait of uan de Fuca is the
presence of ocean swell. National Weather Service does not ever report this, however a good rule of
thumb is to take the reported westerly or northwesterly swell at the western entrance, and divide
that number by three. Add this to the predicted significant wave height to get a reasonable estimate
of the combined seas.

Strong Southerlies, via Dungeness Spit
(Graphic 020)
2 hours 47 minutes 74 nm

With all of our weather routing, our goal is to obtain as much shelter as possible from windward
landmasses, and also to minimize the amount of time we have the seas and winds on our beam. In
the event of strong southerlies, if we are northbound we will seek permission from VTS to transit
west of and then south of the southbound/eastbound traffic lanes to take advantage of the lees
provided by Foulweather Bluff, Marrowstone island and the Olympic Peninsula. At Dungeness
Spit/New Dungeness lighthouse we turn northwest to cross the Strait toward buoy "VH."
Sometimes with strong southerlies or southeasterlies we will see organized 6 ft seas in Puget Sound
and Admiralty Inlet, while the Strait is flat calm.

Strong Westerlies, via Deception Pass
Graphic 030)
4 hours 8 minutes 110 nm

A direct heading from buoys "SA" to "R" to "VH" is 296° T for almost an hour, which makes for a
very uncomfortable ride with strong westerly winds, seas and swell, especially if there is an ebb
running against them. Once north of the international boundary we get some lessened fetch and an
absence of ocean swell from the lee of Cape Calver, but the remaining seas tend to stack up over
Constance Bank to a significant degree. Also it is common for localized winds just east of Constance
to be much larger than in the rest of the eastern entrance of the Strait.

Under these conditions, it is often advantageous to remain east of Whidbey Island to Deception
Pass, then cross Rosario Strait to Thatcher Pass and take advantage of the relatively protected
waters of the San Juan Islands to Speiden Channel. Then south through Haro Strait to Baynes

Note that a strong ebb in these condition will make Deception Pass impassable, in which case
Swinomish Channel may be a better option. Also, it is not advisable to attempt Deception Pass in
hours of darkness, even with radar and GPS chart plotting.

Strong Westerlies, via Swinomish Channel
(Graphic 040)
4 hours 30 minutes 115 nm

Swinomish Channel is only navigable for us when there is at least five feet of tide over MLLW for
the duration of the transit through it. Slowing to a speed commensurate with safe navigation and
also minimizing shoreline damage from our wake definitely turns this into a longer trip. Tugs
towing log booms here and also at Deception Pass often add to the excitement.

Strong Northwesterlies, via Cattle Pass
Graphic 050)
3 hours 34 minutes 97 nm

Simply remaining east of Smith and Minor Islands can sometimes afford some protection; once
inside Cattle Point the rest of the trip is easy. However, some of the roughest seas I have ever seen
in the Strait were between Smith Island and Cattle Point in westerlies, so this option is not usually
my favorite.

Strong Northeasterlies via Davidson Rocks (Graphic 060)
3 hours 32 minutes 93 nm

Sometimes this is a better option than any of the routes which utilize Thatcher Pass, simply because
with northeasterlies Rosario Strait can become very rough very quickly. Another advantage of this
route is that it is quicker than routing throug the San Juans. In some cases if we are uncertain as to
the actual sea state in the Strait, we will head to Davidson first after we exit Deception Pass. Once
at Davidson it will become apparent rather quickly if it isw safe to proceed westward, and if it is not
we can easily duck back behind Lopez Island and head back to Thatcher Pass.

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