Words and photos by Les Rohlf
Anchoring seems to be part science and part art. In an effort to more precisely place the anchor for specific conditions, I’ve been using the following technique, which takes advantage of the sonar, chartplotter track, and windlass. This process has crystalized for me during my time in Alaska for a few reasons: previously we anchored much of the time in a river where current will hold you in place; we didn’t have to allow a factor for tides; and I now have a windlass that allows me to more precisely drop the anchor based on what I’m seeing on the chartplotter.
This picture shows an image of my chartplotter after we’ve been at anchor for a while, but the recorded track helps illustrate the process. The image was taken at our anchorage at Cannery Cove in Pybus Bay. Once in the area I want to anchor, I zoom the chart image to a scale that shows 200 feet in the lower right. I’ll use this to help plot my maximum swing radius. One assumption is that I’ll need 100-150′ of rode to achieve desired scope. The circle described below may be larger or smaller if the needed rode length will be different.
We entered this corner of the cove from the north. We came in near high tide, and I wanted us in at least 20 feet of depth throughout our swing range. Low tide was forecast to be 10 feet less than high tide. The track coming in from the north shows me following (as much as possible) a 30-foot contour.
The lowest point of the track was as close as I wanted to be to shore (not always accurately shown on charts), so I started a circle that would approximate my maximum swing radius (about 150’ radius or 300’ across). We monitor the sonar throughout the circle for any surprises – in this case it indicated progressively deeper water away from shore without being excessively steep. To be even more diligent, many people recommend several circuits of the anchorage to be certain.
Once the circle is complete and I’ve seen no other issues, I turn to the middle of the circle and prepare to drop the anchor. In my case the GPS track is on the chartplotter (near the front of the boat), while the transducer is showing depth and the bottom from the stern. Once I reach the center and am ready to deploy the anchor, I back the boat up slightly to ensure the anchor is over the spot I’ve verified on the sonar display. This is also the point where I set the anchor alarm (something I typically don’t remember). Once the anchor hits the bottom, I want to smoothly idle in reverse as I pay out the anchor rode; this ensures the rode extends in a line and is not just a pile on the bottom. Once I’ve extended the planned amount of rode, I allow it to tighten up. This ensures the rode is extended in a continuous line and the anchor is oriented in the direction I want before attempting to set the anchor.
The track in the photo above shows the turn to the center, followed by backing away on a slightly different line. Once the anchor was set and everything tied off, the wind held to boat toward the west-southwest side of the circle.
The initial circle of the anchorage and its track give me a level of confidence that my swing radius will keep me in deep enough water and provides an objective indication if the anchor begins to drag.
This process becomes more critical in a place like Ford’s Terror where the space to anchor is more limited. In the West Arm of Ford’s Terror, the more popular anchorage there, there’s a fairly short distance between the very shallow (or dry at low tide) creek outlet and 80+ foot depths where anchoring becomesdifficult (or requires a very long rode). The image below shows my track in Ford’s Terror. The top oval section of the track is where I found water less than 20 feet deep (on a 15-foot hightide), which identified an area into which I did not want to swing while anchored. Once anchored I could monitor the extremes of the boat’s swing to ensure the anchor placement did not allow the boat to float into an area that would later be too shallow.
To complete the narrative on our process for anchoring, once ready to set the anchor, I go up to the bow, pass the rode through one of the chocks, and secure the rode to the cleat on the bow. Kel then puts the boat into reverse to set the anchor. Once set, I have a separate line around a snubber that is attached to the boat’s bow eye (on the bow at the water level). I use a rolling hitch to connect this to the anchor rode. The anchor rode is still connected to the bow cleat as a fail-safe, but the force is applied to the center bow of the boat and includes shock absorption of the snubber. This system doesn’t keep the boat from sailing at anchor, but keeps the boat from abruptly jerking to a stop at the end of each swing.
This hope we have as an anchor of the soul, a hope both sure and reliable … (Hebrews 6:19 NASB)
In the next post, Les shares his planning strategies and Kel muses about living on the Intution.