Sailing UPCURRENT on Columbia River

[massnspace]

I am planning a sailing trip from Hood River, Oregon to Pasco, Wa. Small but stable trimaran.

My reason for going against the current is to latch on to the good winds that blow right up the river. But I am concerned about how much current I will have to fight.

I can Google all the “cubic feet per minute” data from the Corps of Engineers, but do not know how to translates that into mph of current.

Anyone out there personally familiar with this stretch of river and can comment?

[Bellinghamster]

I've done a lot of windsurfing in the area and would guess current flow between Hood River and The Dalles to be 2-3kn. Flow rate varies A LOT depending on what they're doing with the dams upstream and the width/depth of the river in a particular stretch.

Just for fun, a "napkin sketch" to quick sanity check: Looking at a chart (https://usa.fishermap.org/depth-map/columbia-river/) and a randomly chosen spot (Mary Hill park) indicates a guestimated "average" depth of about 30ft and the river there is about 600ft wide, so about 18,000 sqft cross section. Water volumetric flow at The Dalles (https://waterdata.usgs.gov/usa/nwis/uv?14105700) varies between about 150,000 and 300,000 cuft/sec. Divide that by 18.000 sqft and you get 8.3 to 16.6 fps or about 5-10kn (which seems a bit high).

Then I found this: https://nwis.waterdata.usgs.gov/nwis...ate=2022-05-18 which shows Ft/sec velocity varies from about 1 fps to 3.5 fps, or 0.6 to 2 knots.

My sister lives in Hood River and sails in the area... I can inquire for more details if you'd like.

[Nikolina]

I worked in the Tri-Cities area several years ago, I stayed on my boat at one of the marinas in Pasco, way better than a motel. It was a 27' SeaSport, I probably fished twice a week after work usually trolling or sometimes letting the boat drift. The average was about 2-2.5 knots in the late summer. Spring run off would be about 5. Winds were all over the board as far as constant or when. Although, as far as weather I think there's a big difference between Pasco and Hood River. Either way it should be fun.

[GordMay]

Divide the flow rate, in cubic feet per minute, by the river's cross-sectional area [in square feet].
Multiply this answer by 60, the number of minutes in an hour [=feet per hour].
Divide the answer by 5,280 [=MPH], or 6080 [=knots], which is the number of feet in a mile [statue or nautical].

[kapnd]

You’ll have to use a contour map to determine the river bottoms cross section, chances are very slim that it has vertical banks and a flat bottom, so depth x width will give you a lower than actual velocity.

[JPA Cate]

Don't overthink it. You can work it out after the fact. If you plan on having 2.5 against you, so that pretty well determines when you'll leave, and then you sail your boat and have fun, then check your arrival time. If it's earlier than you planned on, then it was less than the 2.5, and you had a good trip. The weather and river gods give you whatever they feel like at the moment, and you get to play with it.

It is that where it narrows, it will run more strongly against you, wider areas, not as much. Your tacking angles, as shown on your GPS, will not be nearly as tight as in water with little contrary current.

of course, if you like doing the arithmetic, and are willing to pour over the chart, and compare the depths and distances, you could probably make a drawing showing the current against you at the narrower places and see if that's what you get. For me, sailing is more about the interaction with the elements than the intellectual aspects, but everybody's different.

Ann

[MikeHoncho]

I though cats and trimarans did terrible pointing into the wind? The wind speed on the nose would be my biggest concern no matter what type of boat but higher with a multi hull.