The Anchor Alarm in Aqua Map is easily the best one available. A couple of new additions provide some tools to assist you with anchoring BEFORE the anchor alarm is set. Using these new capabilities is optional but trust me, you’ll want to use them. They assist you by providing live data from the time you start an anchoring process until you’re setting the final anchor alarm position.
There are 4 steps to anchoring and setting an anchor alarm:
- Picking the spot to drop the anchor and stopping the boat.
- Dropping the anchor, setting the anchor position, and releasing chain/rode.
- Convincing the anchor to dig into the sea floor and verifying that it is set and safe.
- Enabling and setting up the anchor alarm for continued monitoring.
This tutorial will address items 1, 2, 3, and part of 4. In general, the word “chain” is used for rode. Some boats use a combination of line and chain while many cruising boats use all chain.
Much of this discussion is also using a technique of having your phone on the bow when the anchor is dropped (“Live anchoring capture” anchor alarm position setting). That method is much preferred over the “After drop capture” selection since live positioning gives more accurate results. If the after drop method is used, much of the real time anchoring assistance described in this document would not be available. But if live anchor capture is used, this process can always be done.
Step 1 - Picking the spot
A general area is often decided upon by looking at charts, using ActiveCaptain markers, or just using past experience. You’ll often move around an area where you want to anchor while watching depths, making estimates of the distances to other boats, and watching other environmental features (staying away from a channel, staying far enough from land, not going near loud boats, etc).
Once you’ve picked your spot and moved to it, you’ll want your boat to stop. And I mean a full stop. Because if the boat is still moving forward and the anchor is dropped, the boat will end up riding over the chain, possibly causing damage to the boat. Dropping the anchor while the boat is moving backwards can start pulling hard against the windlass while it is releasing chain and can damage the windlass or even pull it out of the boat’s mounting. Most windlasses are attached to a boat with 4 or more bolts/screws. In front of the windlass will be some locking mechanism designed to hold the entire weight of the boat. The windlass itself is not designed to hold a heavy boat and moving backwards with only the windlass holding the chain has torn out many windlasses from boats causing severe damage and possible injury.
Consider that arriving at an anchorage often finds some wind and/or current in the area. In those cases, watching the water to determine when the boat has stopped is very difficult. Debris in the water may well be moving with the wind or current and you cannot easily tell if the boat has stopped moving. Even picking a landmark and watching can provide incorrect movement information.
The perfect device to show if the boat is moving is a GPS. It shows the speed against the ground. It can also show the direction of travel because, believe me, you often cannot even tell if the boat is moving forward, backwards, or sideways.
DragQueen had a feature that was very useful in this Step 1 part of anchoring. It allowed the anchor position to be selected very quickly and then immediately provided the distance in feet from that point to your live current position. I would often stand at the bow waiting for the moment to drop the anchor. When I thought we were close, I’d set the anchor position and watch the distance number change. When the distance was changing by less than 1 foot per second, I considered us, “stopped.” At that point, I’d drop the anchor and reset the anchor position point to very accurately record the anchor location for the anchor alarm - I’d even hang over the bow so I could be as close as possible to the anchor position (holding on dearly to my phone).
A new data display in Aqua Map takes this idea of anchor placement and adds even more functionality. To bring up this display, enable the anchor alarm and select, “Live anchoring position.” At the top is an arrow prompting you to point the top of the phone in the direction of the bow. With this orientation of the phone, live directional and positional information can be given that will greatly assist you.
To use this new display, tap the “Capture GPS position” near the top. That captures your current latitude/longitude as a temporary capture for reference to the other information. Current speed will show your live speed and the direction you’re moving from the captured GPS position. Captured distance will show the current distance from that captured position to your current location and show you where the captured position is located relative to your current position. Latitude/longitude values are also provided.
Using this speed and distance, you can decide when you have stopped moving. You can always tap “Capture GPS position” again if you want to start the process over to watch the distance changes more closely.
Above is an example screen shot. The “boat” was slowing down and I tapped the “Capture GPS position” button. That locked the position. While pointing the phone in the direction of the bow, it now shows me live information - the boat is moving 0.2 kts to the right. And at the time of this screen shot, I was 32 feet away from the captured position and that position was to my left. This is a very typical situation where wind or current is actually moving your boat sideways making it very difficult to tell if you are stopped. The raw numbers show reality and are very helpful. Note that you can always tap “Capture GPS position” again if you want to reset everything to your current position.
Step 2 - Releasing chain
Once you’ve decided that the boat is stopped or moving slow enough to drop the anchor, let the anchor go. I typically release enough chain for the anchor to hit the bottom of the sea floor before tapping Capture GPS position to designate the real anchor position. Since the boat is probably moving a little and you could be releasing 20+ feet of chain, waiting to record the position will give a few more feet of accuracy.
So the boat is barely moving, the anchor is on the sea floor, and the anchor position has been recorded as the current GPS captured position. After another 10-25 feet of chain has been released, I ask my wife to put both engines in reverse. We wear wireless headsets to talk to each other during every anchoring/de-anchoring task. Especially with husbands/wives/partners, it removes the need to raise your voice to be heard especially in windy or rainy conditions. Raising your voice can be interpreted as being angry and it can turn a tense situation into a relationship challenge! Headsets remove all yelling. My wife and I can easily and clearly talk as long as we are within 100 feet of each other.
Prior to starting the entire anchoring process, you’ll generally decide how much chain you want to release. That’s often based on scope which is the ratio between chain released and sum of your bow height plus the water depth. For example, I normally put out 5:1 scope if we’re anchoring for a night or 7:1 if we’ll be anchored for a few days. Predicted storms will make me increase scope too. The anchor is more secure with larger scope. I have put out more than 10:1 scope when I knew a storm was approaching.
My boat’s bow is 10 feet above the water line. If the water depth at high tide is 15 feet, then for me to anchor at 7:1, I’ll put out (10 + 15) * 7 = 175 feet. I’ll know this number before I drop the anchor (or something close). I’ll adjust it in my head based on the actual water depth we see (my wife will tell me the depth number) along with an estimate for where we are in the tide cycle.
Continuing my example while using the app, let’s say I want to put out 175 feet of chain - chain is almost always marked on the chain itself and I know pretty accurately how much has been released. The engines are in reverse and I’m watching my phone’s screen carefully while it is showing the live captured distance along with an indication of where the anchor is located (as long as I’m pointing the phone in the bows direction). It’ll be moving by a few feet per second. It’ll show 100…110……..140…145…150… At that point with about 25 feet to go and 175 feet of chain deployed and the chain lock engaged, I’ll tell my wife to take the boat out of gear. Remember, never pull the boat back against the windlass - always use some type of chain lock. We’ll still be moving backwards but I want to slow down with only 25 feet to go. My attention now will mostly be on that captured distance number, watching it slow down as it approaches 175 or so.
Step 3 - Digging in the anchor
Properly digging in an anchor into the sea floor takes experience. I have learned with our boat that you want to slowly persuade the anchor to gently start to dig in and allow it to penetrate the surface very slowly. Without penetrating the floor, the anchor is really only as effective as the weight of the anchor plus the chain. Both of my anchors are 175 lbs and my chain weights about 1 pound per foot. So in my example, I have about 350 pounds of weight trying to hold our 200,000 pound boat. The anchor will never hold that. But if the anchor can dig into the floor, the holding power becomes immense and will easily hold enormous weight.
So we’re drifting back those last 25 feel slowly. The amount of drifting distance I give to the end is based on experience too. If more current was pushing us back, I might start this process at 50 feet. Wind has an effect too. The important thing to know is how many feet we are from the anchor so I can work on letting the anchor dig in.
My goal would be that when the display is showing 170 or so, the chain will start to go taught. That will slow the boat even more. I like to see it drift back a little more and come to a stop or even move a little forward because the chain is now lifted off the floor with the anchor partially dug in - the weight of the chain will pull us back toward the anchor if there’s no current or wind. What I look for is the number to go from 175 to 170 to 165. Then I’ll tell my wife to put both engines in reverse again. This time I’ll let the distance go closer to 175, still drifting back a little to slowly “convince” the anchor to dig in.
One thing to note about distances. None of this is exact. There is a triangle formed between your boat and the anchor. At 7:1 scope, letting out 175 feet of chain won’t perfectly put us back 175 feet when the anchor is dug in because the chain is the hypotenuse of the triangle which is a little longer than the distance back from the anchor that the GPS is measuring. Still, even in 20 feet of water, that 7:1 angle will only account for a few feet of difference so I basically ignore it. If you’re anchoring in very deep water, that hypotenuse length will need to be considered somewhat.
After 2-3 cycles of moving in reverse and watching the captured distance lock at an upper limit, it’ll feel like the anchor is dug in. There’s no way to know but there is a feel based on the bottom material (mud, sand, clay) and the way the chain lifts off the bottom. I’ll work with my wife to put the engines in reverse and hold it there watching the distance number very closely. We’ll hold like that in reverse for 30 seconds. I’ll often then ask her to increase the throttle in reverse to 800 RPM (our idle is 740), and then 1,000 or 1,200. Each change, again, watching the captured distance carefully to see if it moves.
Even at this stage, the distance might change. There is strong pull against the anchor and it might dig in deeper and move back 1-5 feet. If it moves more than about 5 feet or even worse, continues to move back slowly, I’ll stop, move forward (with clear communication over the headsets) to bring in the anchor completely and re-anchor, starting the whole process over again. In our early years of anchoring, we probably re-anchored 20-30% of the time. After 20 years, it rarely happens now - it has been over 2 years since we’ve had to re-anchor because of dragging. It can happen for many reasons but experience helps in getting the feel of knowing when the anchor has dug in. Experience combined with accurate, live data is wonderful.
One other general point. If the data shows that the anchor is not secure and is dragging, pull it in and start over. I know it’s annoying. But do it now and feel comfortable knowing it is secure because otherwise, you can be assured that it’ll cause a major problem at 3 am.
With the boat in reverse and the display showing that the distance is not increasing, I’ll tell my wife to slowly take the boat out of gear. The boat will move a little forward. I’ll close up the windlass controls, and tap the “End procedure and Set anchor position” on the phone display. This transfers the captured GPS position to the anchor alarm position. Now my anchor alarm position is set based on the data I’ve been working with to dig in the anchor. I know the maximum distance the boat was when it stopped moving back. This gives me an idea for setting the anchor alarm radius, warning area, alarm delay, and other anchor alarm settings.
If using these new Aqua Map capabilities are new to you, experiment with it in a large parking lot. It’s easy to simulate moving to a spot, capturing the position, slowly moving back, and getting a feel for the display nuances. Really - play with that a few times before you decided to use this new display for real. When you’re in the middle of the anchoring process, there’s a lot going on. Being comfortable with the process and the data displayed will make anchoring less stressful.
May your anchor dig in well and may you stay safe and comfortable at night on the hook. Especially if you’re anchored in front of me!
Jeffrey Siegel, MV RED HEAD.
