Inside Passage Blog

By Linda Lewis

 

 

July 1, 2007 – Another Navigation Challenge Explored at Swanson Harbor

 

Here is another navigation-challenge tale. There is a spot in SE AK where an enticing shortcut exists. It is right at the junction of Icy Strait, Lynn Canal, and Chatham Strait at a place called Swanson Harbor. The shortcut between Swanson Harbor and Couverden Cove means a savings of several miles out in waters that are frequently pretty windy, often with nasty seas. However this is a very dicey little shortcut and is best done only by dinghies or larger boats with solid "local knowledge" of the shorcut. That means doing what I did after we were docked: reconnoiter the shortcut by dinghy and decide if you really want to do this with the "big boat."
 
We had not been to Swanson Harbor before so I was very curious to check out this "Coverden Channel" shortcut myself. We knew there were two public floats in Swanson so we were watching for them as we entered the bay. But we first saw these odd looking, really large poles in the distance. Strange. That didn't look right for public floats.

 
 
Oh, here are the two floats off to the right. So we picked one and tied up the boat.

I was determined to go check out those poles. They are (non-Coast Guard) markers meant to guide boaters through the shortcut channel. They were much taller and than I had anticipated. I hopped into the Green Devil on a falling tide with just a few minutes to spare and went off to dinghy through this channel with camera, GPS, and pen and paper in hand. Before reaching the west end of the channel markers I had to be sure to skirt this hazard called: No Use Ledge.

And here are the channel markers. This is pole #1 (green). (The green tells boaters that  -- when entering from this end -- all the greens should be on the left side of the boat.) The tide level here can reach about 18 feet above charted depths. It can also go below the zero mark on a "minus" tide. Most (but not all) of the rest of the markers were substantial metal poles.
 
There are five sets of poles. Each had a colored flag with a number. In this picture you see in the distance: 3 & 4, 5 & 6, and 7 & 8. The width between the poles is approximately 40 feet so there is not room for a large boat to do any turning around. Once you start through you are committed.

As I approached the shortcut's west end (in Swanson Harbor), there appeared to be just enough water covering the bottom of the channel to slide the skiff through and back. Fast! Before the water level dropped further. (The skiff draws 18" with the motor down; as it turned out there was about 2 ft - 5 ft throughout most of the channel.)
 
The green-marked pole is # 5. The red in the distance is # 8.

Here are #7 and # 8 shown together.

And here is # 9. Oops, something happened to this pole for sure. And # 10 was completly missing.

I didn't have time to ponder this mystery very long as the water was continuing to drop. I quickly did a 180 and started my way back through the channel.

Heading back.  Hmm. The water is already more skinny. Hurry up Linda.

Getting there.    Kack! Kack! Kack! Kack!   Argh.   Get that motor up higher!    OK now.    Keep going.    Watch the bottom more closely. 
 
Yes, I confess. I managed to add a few little nicks to the prop. (It was, after all, a bit difficult to drive, take pictures, and record GPS coordinates all at the same time.) David was kind about the prop and only gave me a slight frown and shake of his head.
 
When I got back to the dock we helped tie up this boat. The skipper intended to go through this very same channel at half tide later in the evening. He had a 3 foot draft and lots of local knowledge as he is a charter vessel. He says he has been through there many times and goes at anything above half tide. (His timing for the upcoming passage would give him about 7 feet of water. He was satisfied with just 4 feet under his keel.)
 
I decided to do some more exploring of the channel the next morning.

In the meantime, I  had another ..." You look really familiar" moment. We were at the Swanson dock with yet another boater that had attended the Douglass Inside Passage Seminar: Simpatico.

These folks brought the boat from Seattle to Juneau, where they live. They were out playing for the weekend and decided Swanson was a convenient stop. 
 
The next morning we had a minus tide of 1.9 feet. The shortcut channel is bare on that kind of tide, so I decided to return right at the lowest point in the tide cycle and WALK the channel this time. That way I could get really accurate GPS coordinates. (And it certainly protects the skiff's prop doing it this way.)
 
Blaine (Simpatico) was also curious about the shortcut channel so he went with me on my morning excursion. As we dinghied over I discovered that he is retired Coast Guard so I had a real professional with me to witness my coordinate-gathering efforts!
 
Here is what we found. Those are poles 1 & 2, with 3 & 4 and 5 & 6 in the background. Poles 7 & 8 are way off in the distance.

We pulled the skiff up and set its anchor (around the pole!), then started out on foot.

What a sight.

Poor David got roped into the project by proxy. I couldn't get my pen to work in the misting rain so I radioed each coordinate back to him to write down for me.
 
The water was no more than mid-calf puddles as we walked through the channel. After poles 5 & 6 (seen here), there is a left turn in the channel.

And we solved the mystery of the missing pole # 10. It has been knocked down completely and was lying in the channel.

We could see why this end of the channel (east) is the tough end. As we looked out from the last set of poles, this is what we saw at the minus tide. A scattering of rocks that must be threaded through. We sighted the rock/reef beyond the last bar (barely visible left of center in the picture) and decided we would probably need to keep that to the left of our exit course.

When I returned to the boat I entered all the coordinates and looked at the chart for the rocks noted at the East end. I plotted my impressions on the electronic chart and did a screen capture. The purple icons are the lat/longs I gathered through the actual marked channel; the circles are waypoints of the route that I estimated would complete the exit. Here's the result of my little research project.


Click Chart to Enlarge

And what were the final conclusions? Blaine said he was glad to have scouted the channel and would now probably take his 32' (3 ft draft) Simpatico through the shortcut at high water in good weather. OK, what about Royal Sounder (45' long; 4-1/2 ft. draft)? My conclusion was no. It would not be worth taking the chance in our boat.
 
That's exactly what reconnoitering is meant to do: help you make decisions about what is right for you and your boat.
 
David thinks I'm nuts putting so much time into things like this. But the reseacher and explorer in me is still alive and kicking. I consider doing things like this part of the fun of boating for me!

Linda & Dave
M/V Royal Sounder

 

 


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