Descaling Engine Heat Exchangers [and other raw water plumbing...]

Is your engine starting to run warmer than usual?

Based upon this descaling article in Practical Sailor, we chose to use CLR (among several tested and rated products) annually to descale the raw water circuits on our propulsion engine and generator (which include several copper-nickle heat exchangers.)  

CLR is also safe to use on the dibghy outboard engine since there is aluminum to be found in its raw water cooling cirsuits.

We chose CLR because it is safer to work with, has no fumes (unlike muriatic acid...) and CLR won't harm any aluminum (or anodes) in the raw water circuit when used as directed in the above article and per manufacturer's instructions. 

CLR is also effective at removing rust stains, cleaning the shower floor and walls, clearing air conditioner/ heat pump raw water circuits, descaling coffee pots, outboard motor cooling circuit, etc., etc. (Everything on a boat should have more than one purpose, right?)

Instead of removing the various heat exchangers and soaking in a bucket, we leave them in place and use a small pump to recirculate 50% diluted CLR (per above linked article) through the raw water coolant loops of the main engine and generator annually.  

If you prefer to purge any raw water from the cooling circuits before descaling, pump some fresh water through first- discharging into the bilge instead of the bucket. Then put your hoses in the bucket of diluted CLR and turn on your recirculation pump.

Recirculating 50% diluted CLR clears the deposits in the raw water side of the heat exchangers. 

Keep it going until the discharge stops foaming.

       

The time elapsed between above photos was ~ 2 hours. (Severe deposits can take hours longer- even overnight...)

The red return line in the above photos is the disconnected exhaust elbow raw water injection hose on our generator (you wouldn't want to hydrolock your engine with the descaling recirculation pump...)

The black hose is the suction hose which normally goes to the raw water through-hull (strainer) for that engine.

 

This is a routine part of our annual maintenance. It also provides an opportunity to inspect the exaust elbow injection site for corrosion since we have to remove that hose to recirculate the descaling solution.

When we are finished with each engine, we dump the bucket of used CLR solution into the bilge with the primary (lowest or maintenance) bilge pump off. (We have several bilge pumps installed- each above the previous- and they are left on, so are covered in an emergency...) 

After adding the 2nd bucket full, we turn on the maintenance bilge pump for a few seconds to fill the discharge hose, and then turn it off again to let everything soak overnight. To empty the CLR from the bilge, capture the bilge pump discharge and dispose of properly. 

Three-way valves strategically placed in the bilge pump discharge and engine raw water hoses mentioned above make this annual maintenance quick and easy with no hoses to remove... (With well planned 3-way valves you could even use the bilge as the bucket, and the maintenance bilge pump to recirculate the descaling mixture...)

Win-Win.

 

______________

Links to related forum discussions:

Nauticat USA Forum 29-Jan-2023 

Cruiser's Forum 27-Jan-2023

Hull strainers can be blocked too...

Recently, while running the generator at anchor, I noticed the gen exhaust water splash had abrubtly stopped, and shut it down right away...

I started troubleshooting by looking at the raw water strainer for the gen set. It was full of bits of jellyfish- but not so full as to prevent water flowing still...

The boat has external strainers [images below] on the hull for engine intake through-hulls, so the suction must have extruded pieces of the unfortunate organism.

Generator

 Engine

 

Backflushing with pressurized water didn't work. I had to fire up the engine and run the prop in reverse to blow the jellyfish off the strainer. 

I doubt this would happen while underway, and was surprized it did while sitting still... 

Murphy prevailed- to the detriment of the jellyfish...

Moon Jellyfish [Aurelia aurita]

Lights out...

Under the heading of When Things Go Wrong...  [Or Sh.tuff happens...]

In summer 2018, peacefully at anchor one sunny afternoon, our 12V DC power shut down.

Everything off. 

No sound. No sparks. No smoke. No smell. No alarms. Zippo... Nada...

And no battery power... anywhere...

Ruht Roh...

And no high load before this occurred [just the usual stuff averaging ~12 amps 12V DC…]

It was as though the 350 amp primary feed fuse at the batteries silently blew [which was my first fleeting thought…]

I decided to do some tracing and grabbed a VOM to test for voltage on the [few] 4/0 positive [and negative] cable connections starting at the battery bank.

12.7V DC at the batteries— before and after the 350A fuse [which protects the boat from a direct short in the 4/0 feed from the battery bank.] Good.

Hmmm… the alternator on the engine still has 12.7 volts…   [This also means the high amperage fuse connecting the alternator output to the battery bank isn't blown.] Good.

Next in line is the emergency DC power disconnect switch in the pilothouse. This switch kills all power from the house battery bank to everything on the boat except the engine starter and alternator... so I continued there [after first confirming it had not been accidentally switched off—  by no one in particular...]

OK; 12.7 volts on the input [battery] side of the switch… Good.  
But zero voltage on the output side... Hmmmm?...  Not even a fraction of a volt? 

Not good... [Yup, the switch was on— and cool to the touch…]

Hmmmm?…

I toggled the switch off and on a few [dozen] times [Hoping for what exactly?... To remove corrosion on the contacts? Or toggle contacts fully into position? Or make is magically start working by touching it...?] 

No such luck... No change... Still no battery power.

Apparently the switch just suddenly [and silently] died— and with just the ambient 12V DC load… [e.g., No surge of current from running a welder off the inverter... I exaggerate…]

Having no spare switch onboard [but several in our storage facility...] I ended up just bypassing the switch to put us back online. [Thankfully, the switch was the only culprit— the root cause of this issue.]

This seemed absurd at the time because one never expects a high amperage switch that has maybe been cycled a handful of times in its life to catastrophically fail out of the blue— especially with no appreciable electrical load…

On the plus side, that is the right way to fail… [vs. discovering you cannot disconnect battery power... in an emergency…]

Remember, this is the switch to be quickly turned off in the event the symptoms listed above present themselves... [Smoke, sparks, 'electrical smell', lights dimming and flashing, etc...]

What happened?

After I removed the switch, I noticed one of the 3/8″ cable connection studs on the back was loose; the other wasn’t. I suspect a connection inside the switch [solder/weld?] just suddenly yielded, unceremoniously breaking the circuit. [I didn't care enough to tear it down as it was to be replaced with something different... more below...]

Perhaps the  4/0 cables hanging on it induced a strain that over time broke the bolt’s connection to the switch? [Inadequate strain relief? The cables were firmly secured mere inches from their attachment point on the switch... Perhaps it was over tightened when installed in 1999 by the previous owners? Manufacturing/design defect? Poltergeist? Who knows...?]

But— remember our story started out that it was a warm and sunny afternoon… so it wasn’t all that bad… 

Doesn't Murphy mandate events like this are supposed to happen when it it is pitch black and stormy, the boat is bucking at anchor like a bronco, and you have only been asleep for an hour after a long day, and perhaps you are even coming down with the flu, or are seasick…?  [Oh, and the first 3 flashlights you grab have weak batteries...] Catch my drift?...

Looks like Murphy gave us a pass this time... and...

The dead switch has since been replaced…

The new 300A [continuous; 500A ittermittant] emergency cut-off switch [shown with key removed...]
[Different manufacturer from the one being replaced...]

Our lessons learned include: 

• Always troubleshoot from the bottom up [To determine the root cause, start with the roots... and don't ignore other possible contributing factors...]
• Never assume you immediately know what has happened [Don't believe everything you think...]
• Be prepared for any component to fail without warning or apparent cause at any time [AKA Cruising...]

Are there any proactive measures or any preventative maintenance to help mitigate something like this from re-occurring?  

Search me... Leave a comment... I'm all ears...

This post began life as my reply to the question:

"What’s the most ridiculous repair you’ve done on your boat?"  

[Asked by our friends on SV Galapagos in their We're in Hot Water post;  7-Mar-2019]

Friday Funny Finally 09-20/19 (Take The Good, with the Bad)

We're back in the internet world, so we can read some news, do some banking, order off of Amazon, and most importantly, write a Friday Funny.

We had a glorious day, a safe transit out of Ford's Terror, (as usual, going places with scary names), a stop to scoop up glacier ice for the cooler, or call it a MOB(man over board), drill with a net and small ice bergs, bears, seals, whales, a sunny day, a beautiful bay for anchoring, solitude, and 30 shrimp in the pot. What could spoil this? A broken throttle cable to the outside helm, thats what.

Off of Endicott Arm, we're going into Ford's Terror.

A close up of the chart for the "scary part". 

The opening into the narrow chokepoint can build up dangerous tidal currents, and should be transited at high slack, (at the peak of incoming tide, with no movement, before the tide reverses out),  This entrance can build up to a 2-3 foot waterfall, there are videos on youtube of people surfing here. We entered at low slack, (at the peak of outgoing tide), because that's how we roll, or float actually, Bill likes a challenge. A couple of days later, we left at high slack, timing was good for the departure.

The illustration from the "Exploring SE Alaska guide by Douglass/Hemingway". Check out the note at the far right top, "unsurveyed", most of Ford's Terror is unsurveyed, and very deep because it's a fjord created by glacial movement.

Line up your stern with the double waterfall for the entrance.

Narrow entrance, we're keeping an eye on how fast the current is moving. 

We lined up with the entrance three times before we determined that the current had slacked enough for a safe transit.

Made it, around the corner.

Tall sheer mountains on all sides, with plenty of picturesque waterfalls.

Mama black bear and her cub showed up daily.

On the morning of departure, we pulled up our shrimp pot, success! Dinner at our new anchorage will be shrimp.

Fresh spot shrimp, very tasty.

Motoring down Endicott Arm, avoiding icebergs, and small growlers, we saw seals lazing in the sun.

Those dark spots are seals, we keep our distance, so we don't disturb them.

Leaving Endicott Arm, we cross Stephens Passage, and head up Seymour Canal. I'm standing in the cockpit on watch, and suddenly I yell, "Whale, 9 o'clock!" (Clock directions) What a show!

Tail Slaps

Fin Slaps

Fin, and tail slaps, as well as breaches sound like gun shots, and they echo off of the mountains. We anchored in Pleasant Bay, and the whales kept up their sounds, feeding, slaps, and breaches for a solid week. We saw/heard them all day, and all night, it's the most whale action I have ever seen.

Looking out Pleasant Bay

These two seemed to have a contest, who could slap the loudest.

 So what could mar this beautiful setting?

Just as we were leaving Ford's Terror, and entering Endicott Arm, we saw some small glacier ice floating nearby, and it was about the size that would fit in our cooler. Bill grabbed the net, and I was at the helm, doing forward, and reverse to get close enough to snag the ice. It's called back, and fill, to pivot  the boat in place, and I'm not very good at it, so this was good practice for me. Suddenly it seemed like I wasn't getting any power when I shifted into forward, or reverse, meanwhile, Bill is calling to get just a little closer to reach the ice. I advised him, "um, no can do.... " So now we're drifting along with the bergs, some small, some large, and Bill is still wanting to get ice. He manages to snag a couple, puts them in the cooler, (I'm getting antsy... thats all I'll say about that), and he goes to the lower helm to see if we can get propulsion. Our two helms work independent of each other, and when one is engaged, the other is locked out. The good news is that if one breaks a throttle cable, the other one still works because it has it's own cable.

Glacier ice in the cooler, it's so dense, it lasts a long time.

Not much could be done while we were underway, so we set the lower throttle to speed, and did most of the steering, and use of the autohelm in the cockpit. Once we had anchored in Pleasant Bay, he dived into the possible problems, and solutions. He took the plate off of the binnacle, I think it looks scary in there, but Bill knows what he is looking at.

Arrow pointing to the throttle cable.

The cable broke off right at the top connection to the housing that connects to the shifter arm. If you want a more technical answer, ask Bill, I'm not the one to provide it. 😀

Cable connection point.

Two throttle controls to the Ford Lehman.

Bill managed to make a connection good enough to get it working again, and we're headed back to Wrangell to get a new cable, and a spare. Having spares is a handy thing.

We're at an interim stop in Petersburg to see friends, and check their chandlery for parts.

Gratuitous photo of Gus taking all events in stride. 

The usual cruiser mantra, "fixing your boat in exotic places", is a true statement.

As always, we enjoy hearing from you, either here in comments or on our Facebook Denali Rose Sailboat page.

Friday Funny 07-05/19 (Impeller, Propeller)

Since I have connectivity, I thought I'd post this early.... or late from last week, you can take your pick.

We hope you have a Happy Fourth of July celebration.

We're in Craig AK, on the southern west coast of Prince of Wales Island, and our unlimited data plan card is not finding a connection, and our cell phones that we use as hotspots are soooooo slow. I'm just trying to update crucial apps like AYE TIDES, SEAiq, and AQUA MAP, Audiobooks, stuff we use daily. Writing a blog post, becomes lower on the priority list, again, but I'm trying.

Labouchere Bay

While we were in Wrangell, Bill helped out many boat neighbors with their batteries, charging, monitors, and electrical issues, and didn't have time to do some of our maintenance before we untied, and left. He assured me that he had everything we needed to do our chores after departing the dock. We've had some issues too.

Bill changed the way Denali Rose's batteries were connected to the monitor, so the readings would be more accurate, and replaced the alternator for a new one. That system is now performing much better, and with the increase in power, as well as the solar panels he installed last summer, we are charging the batteries faster, and higher. A WIN!

We had noticed the raw water cooling for the engine, (Ford Lehman), was putting out less of a stream than normal, so Bill changed out the impeller, and used some lime-away in the heat exchanger units. He used one of the impellers from the stores of extra supplies that came with the boat when we purchased her 5 years ago. Afterwards, it didn't look like we were getting a bigger stream of water, and the engine was running just a little hotter than normal, not an issue, so we departed our anchorage for the days travel. Just as we left the protected bay, and into Sumner Strait, 15-20 knots of wind, 3ft seas, the engine started to overheat, and Bill shut it down. He left me to keep watch, making sure we didn't drift into anything dangerous, to keep an eye out for traffic, and went to check things in the engine room. Without any propulsion, Denali Rose turned broadside to rollers, waves, and wind, not fun. Bill didn't find anything obvious, suspecting the new impeller, we turned the engine back on, and motored very slowly back into the bay. He let the anchor out over the bow, and depended on the wind to pull us back and sink the anchor into the bottom mud.
Pulled out the "new" impeller, and fortunately, we had a newer spare. The rubber on the original spare had stiffened up so much it was brittle, and had destroyed itself, the new one, which was just purchased,  was still flexible.

Busted up first replacement impeller on top, and newer replacement one on bottom.

New(er) impeller installed, eureka! Great water flow from the cooling system! Another night in the bay, and we're good to go, no more over-heating issues. A LOSS, and a WIN!

We found two more spares in the Napa Store here, in Craig, so now we have 2 old spares, which we probably won't trust, due to age, and 2 new spares just in case. (If you've been reading this blog for any amount of time, you'd know we're into redundancy....)

We also had a diver clean off some growth on our prop which was probably causing a slight vibration while underway, and replace 2 small anodes. The small community of Craig has been a WIN/WIN.

We're outta here, and will be back in the no wifi, no cell signal mode again. We're headed back north to rondezvous with a friend on his Nordic Tug, and buddy boat even farther north. 

Bill usually updates our "Where's the Boat" on Farkar, apparently we're north of Ireland. 

Very funny..... but if you want to see our progress, that is usually the link to check. 😀(Top Right)

As always, we enjoy hearing from you, either here in comments or on our Facebook Denali Rose Sailboat page.

Tidbit: Sleeping well at anchor... [Updated Feb-2026]

This is one of a series of brief, no nonsense posts that we call a Tidbit: 

noun; small and [possibly] particularly interesting item of gossip or information...

The purpose is to share succinct posts about lessons learned, or things we use or do that work [or don't...] that are common to most of us boaters. 

The goal is to garner feedback from those of you having first-hand experience with a different approach/ solution/ product/ or additional useful information to share...  

We never assume what we are sharing is the ideal or only; it just seems to best suit our needs [and/or habits and/or budget] from our experiences thus far...

Note: The original blog post [below] has been inducted into Tidbits since it qualifies, but was originally published almost 2 1/2 years before we initiated the Tidbit series in Jan-2019... 

[First published 24-Aug-2016]

                        ➛ ➛ Peruse the right-hand sidebar for the up-to-date list of Tidbits ➛ ➛                        

One of the many joys of cruising is the feeling of liberation once you gain trust in your ability to anchor, in your ground tackle, and your method(s) of maintaining situational awareness. 

Denali Rose at anchor in Traitors Bay, Alaska [Near Ketchikan...] Great bear viewing area for only a 1/2 mile walk on shore... Hence the occasional float plane brings a load of cruise ship passengers for a quick tour.

Here we are anchored in 80 ft with rocks not necessarily close to shore bared at lower tides in several quadrants, and a large, very rapidly shoaling head of the bay which is aft of the boat in this photo.  [e.g., if the anchor dragged, the depth change is so abrupt, we would go aground before the anchor reached an uphill portion to reset upon...]

Just another typical anchorage in paradise...

Trustworthy anchoring is not unlike that feeling of accomplishment earned once you can quickly- and repeatedly- parallel park an automobile in a tight spot on a steep, icy road in heavy traffic. Not everyone gets there...

But this is not a discussion about how to anchor [nor parallel park...] This is about being able to relax afterward, while maintaining awareness... 


What do we do? [Nothing unique...]

• Trace our route into the anchorage in case we need to follow it out in the dark
• Anchor like we're expecting 60 knot sustained winds [Force 11] with higher gusts
• Capture the coordinates of the anchor
• Take bearings on landmarks when possible
• Set at least two proven and reliable anchor alarms
• Set wind and depth alarms
• Keep broadcasting our position on AIS
• Illuminate the boat well at deck level- to supplement the masthead anchor light
• Set a RADAR guard zone [when the situation warrants]
• Stay aware
• Set an anchor watch if needed [at least then everyone else can sleep...]

Details:

We begin by always recording a GPS track on one or more chart plotters when transiting, and especially when entering an anchorage area. [Many have tricky entrances and some require certain stages of tide as well for either optimied depth or current- or both...] 

That gives us a trail to follow should we have to bail-out of our anchorage in the middle of the inevitable tempest in the dark... [The author learned this the hard way.; a long story from eons ago (pre-GPS) but with a happy— yet expensive— ending...]

While still tracking, we scout the area(s) where we would like to drop the hook by slowly driving in a circle repersenting the anchoring perimeter. This is how we evaluate the bottom and any obstacles within our chosen anchor zone... Our forward looking SONAR is also used during this stage. 

Before dropping the anchor, we will place the boat at the position we believe we want to drop the anchor [the center of the previously scouted perimeter] and perform a 360° turn-in-place [a back and fill maneuver...] to map the bottom with the forward facing SONAR from the anchor's view if you will. This is helpful later as we watch our swing at anchor. [Are we staying within the anchoring area we already scrutinized?] 

This also helps us to properly calculate the anchor scope required at high tide- especially on a bottom with uneven depth where the depth can often change by 100% or more depending where the boat is in the circle of swing... 

Side note: The 15-20 foot tidal variations in our present cruising area have negligible effect on the diameter of the circle of swing at anchor. [Use Pythagoras' Theorem to demonstrate this to yourself...] However, the scope ratio is affected more in shallower anchorages [rare for us...] when tidal fluctuation is a significant percentage of the depth.

We always mark the anchor location and continue GPS tracking on the chartplotters and navigation apps once anchored. It is very informative to see where we have wandered while on our leash. [This is automatic on our Vesper Watchmate Vision; more below.]  It is also extremely enlightening if conditions worsen or we start getting hit with williwaws [a type of katabatic wind gust.]

Next, we always anchor as though we expect it to blow 60 knots. [Force 11] It only takes about 5 extra minutes to do this every time [and that includes deploying a bridle...] Because of this we rarely have to get up at o-dark-thirty to deal with an anchor related issue. [Our own anchor anyway...]

Okay. We're anchored. Now what?

Diligently maintain situational awareness while we enjoy doing other things...

This means staying cognizant of our boat's position with relation to land; other vessels and obstacles around us [above and below the waterline...]; the tide, weather, etc. 

When we anchor with the intension of leaving the boat [e.g., kayaking, a shore trip, visit another boat, or whatever...] we always wait at least an hour after anchoring to confirm our swing [wind/tide] at anchor is as anticipated, and that the anchor location doesn't move without our knowing... This also gives us time to recheck the weather, tide, anchor scope calculations, etc...

How do we maintain situational awareness full time while at anchor? [Hint: You can't if you ever plan to sleep...]

Since we spend a majority of our time in our pilothouse when on the the boat at anchor, we are always visually aware of what is going on around us [except when very dark or when sleeping...] If we are concerned about anything around us, we sleep in the pilothouse where, with just a sit-up, we can quickly glance outside. If an anchor watch is needed, the pilothouse is a comfortable watchstanding location in foul weather...


What about when we both sleep with no anchor watch? [i.e., normal circumstances...]

We typically set multiple anchor alarms, may set RADAR guard zones, always transmit and receive AIS, always depth and wind alarms, and sometimes marine radio(s), etc. as needed.

On prior boats in the days before GPS [and then for a time, dithered GPS; hence no accurate anchor alarms] a tell-tale compass in one's berth area was somewhat handy to help with orientation when awakened at anchor and during a passage. But it didn't show one's position nor surroundings. One had to get up and look around.


Another habit from the old days is taking some bearings on lights, landmarks, etc. I can also spot in the dark. [e.g., lights, some high points on land (e.g., unique trees, rock formations, mountain tops, etc.)— the silhouettes of which would be discernable in the dark.]

Now, we always set anchor [and depth and wind] alarms on our Vesper Watchmate Vision AIS transponder. We will often also set an anchor alarm one of our Zeus2 MFDs. 

And depending upon circumstances, we might also set one or two tablet anchor alarms and RADAR Guard Zone alarm(s).

If we are within cell phone range and plan to be away from the boat, we used to* also set a geofence on our remote vessel monitoring system— essentially a remote notification anchor alarm [among other alerts... e.g., bilge pump, battery status, etc.]

* Our older remote vessel monitoring system was dependent upon 2G cellular data— which has been deprecated worldwide. We haven't upgraded yet. 

We can also set up remote anchor alarm notifications using two iPhones [one on the boat] using the Remote feature built-in to several navigation apps. [More below]

What Anchor Alarm apps do we use on tablets/ smartphones?

[Also see the Additional Resources section at the end of this article for more info.]

For back-up anchor alarms [on our smart phones or tablets] we currently use either Anchor! and/or the anchor alarm function built into the AquaMap Marine or TZiBoat charting apps. Thus far we find them both to be the best, most robust, adjustable, and detailed graphic anchor watch applications available...

As brought up in the comments section, below, false alarms can be a sleep-depriving nuisance when using anchor drag alert apps. [Usually due to momentary loss of GPS signal— and in the case of our Vesper Watchmate, momentary loss of wind or depth data on the NMEA2000 network.]

What might help? Add user adjustable delays before an alarm is sounded, and more granular sub-settings.

As an example, AquaMap Marine has the best alarm tunability I have seen so far:

Update Apr-2023: AquaMap announced cell phone to cell phone anchor monitoring so you can be alerted if your anchor drags while away from yor boat [in locations with cell signals at the boat and your location. [Not shown below.]

For information about other boating related applications we are using/evaluating, see our maintained page about Computers, Devices, and Applications.

All redundant alarms are set with ever increasing- but safe- parameters. The goal is for them to sound one at a time [if things are happening slowly...]

Setting several alarms takes very little time and provides the needed redundancy for our comfort. [On those rare occasions when it is important to be awakened by an alarm clock (e.g., to catch a flight) we set two; this reduces inclination to wake up toandpeek to see of a single alarm failed to awaken us...]

An important note about the geometry of anchor alarms: 

Are you familiar with the GPS position error [up to 2x...] so common in most anchor alarms? If not, read this article from Boat US- which includes description of a fail-safe technique for setting two alarms on different apps.

Note that Vesper AIS transponders with anchor alarms updated in 2016 compensate for this error, as do the two apps I cited above.

Do you know of other products that compensate for this error? Please let us know by leaving a comment.

We also each have tablets with very accurate built-in GPS running navigation software as well as a mirror of the MFD showing the vessel's position and an overlay RADAR image, etc. These are always within reach- especially when sleeping.

If expecting weather or vessel traffic, or if either occur unexpectedly, we set zone alarm(s) on the RADAR [our 4G consumes very little power...] to warn of other vessels [or land, etc.] encroaching on our comfort zone. 

The RADAR image is also viewable on our tablets- which is handy when awakened by a RADAR alarm while sleeping. We can quickly assess and mute the alarm from the tablet, and of course get up if necessary, or roll over and go back to sleep if not... [e.g., a dinghy passing through our RADAR watch zone is not worth getting up over unless they are coming to see us...]

Changing the depth alarm to suit is also important to us on those rare occasions we anchor in water shallower than 60ft at low tide... [This is another anchor watch function of the Vesper Watchmate Vision AIS.]

The Vesper AIS also allows us to set wind alarms [directional and/or speed changes.]


If we could only set one anchor alarm, which one would we choose today?

Without question it would be the Vesper Watchmate Vision AIS. [It is always set first regardless...]

If we didn't have the Vesper, then we would choose one or both of the anchor alarm apps mentioned above. [Which we typically use as back-ups anyway...]

Update Feb-2023: Vesper has been acquired by Garmin. Garmin has decided to discontinue all Vesper AIS models except the Cortex. The Cortex has an even better anchor alarm that what we describe here. We will continue to use our Watchmate Vision AIS until it no longer serves its purpose.  

Why is the Verper our unequivocal first choice? [From the manufacturer's website:]

Safety at Anchor – Anchor Watch

Every sailor knows that being at anchor is no guarantee of total safety. In particular, anchors can drag without those on board being aware. Thanks to Anchor Watch, however, you can be safer and sleep well at night. That’s because Anchor Watch sounds the alarm if you drift outside a zone defined around your anchor position. Activate the anchor watch when you drop the anchor touching the Vision screen or using a mobile device to activate it remotely from the windlass or anywhere on-board.

Wind speed, wind direction change or minimum water depth alarms

Get added safety at anchor by setting wind speed, wind direction change and minimum water depth alarms and take quick precautionary action when these alarms are triggered.

Move Anchor Position

If your Anchor position needs fine-tuning after you have marked it, you can do that with the Move Anchor Position.

Breadcrumbs.

Vision plots your position in relation to the anchor and marks your positions over time for easy visual identification if you are dragging. It also works well on smartphones and tablets.

Anchor Watch on our Vesper Vision

Enhancement suggestion for Vesper [Now Garmin- which deprecated this model…]: 

There is one feature I believe would make the Vesper Watchmate Vision Anchor Alarm even more useful; being able to choose screen orientation.  [Update: Now available on their Cortex model.]

Currently it will only display North-up. There are times when it would be far handier if it would display Heading-up. However, I realize this could make the view jump around and not be useful in certain circumstances...  [But then we could switch back to N-up just like a chart plotter...] 

What about the flip-side: helping others become aware of [and see] us?

Proactive measures include:

RADAR: To improve the chances of returning a strong RADAR signal, we have a large Blipper radar reflector mounted high on the main mast. [I imagine some may wonder why we stow a fender way up there...]

AIS: We also broadcast our position on AIS 24/7 when away from a dock. Additionally, our Vesper Watchmate Vision AIS transceiver allows us to tune alarm thresholds for different scenarios [including AIS Filters, depth, and wind direction and velocity.] Therefore, while at anchor we don't have any distant vessel alerts waking us up- only potential close encounters as established by values we set... [And the AIS is wired to an optional, very LOUD external alarm...]

Like our B&G Zeus2 MFDs, the Vesper Watchmate Vision is viewable [and controllable] via WiFi on our smartphones and tablets...

Improved Visibility: To enhance our vessel's visibility to others when we are at anchor in the dark [remember it doesn't always get dark overnight in higher latitudes during summer...] in addition to the masthead anchor light, we also deploy 2 portable anchor lights; one on the inner forestay on the bow about 12 feet above the deck [and under the black anchor ball day shape] and one amidships- typically inside the cockpit enclosure to serve two perposes. We have a 3rd anchor light [like the portables but with a mounting bracket] permanently mounted on the stern davits- which also serves as a 'dinghy garage' light...

Article discussing where to display your anchor light(s).

And what do the international rules say? (COLREGS Anex I)

(i)All-round lights shall be so located as not to be obscured by masts,
topmasts or structures within angular sectors of more than 6
degrees, except anchor lights prescribed in Rule 30, which need
not be placed at an impracticable height above the hull.
(ii)If it is impracticable to comply with paragraph (b)(i) of this section
by exhibiting only one all-round light, two all-round lights shall be
used suitably positioned or screened so that they appear, as far as
practicable, as one light at a distance of one mile.”

Here is an excellent article in Practical Sailor covering supplementary anchor light choices.

 

Denali Rose from ~2.5 miles- taken with a smartphone camera from our dinghy.

Masthead anchor light is off in this photo; you are seeing 3 of these portable anchor lights. Bow is on the right in this photo. (Highest light.) There are no shore lights or other vessels in this (calm) anchorage- which is the norm for us. [Note that the snip of red light seen in the photo is showing through a cabin port; i.e., it is not a NAV light.]

These deck level anchor lights are visible for 2+ miles and, since they hang upside down, do a nice job of illuminating the deck, too. This makes our boat very visible both from both water level and a distance. [Mast head anchor lights are difficult to spot/ triangulate from water level when close-to. Ours is 60 feet above the water, so we rarely use it...]

All [4] of our LED anchor lights have dusk-to-dawn photo sensors, so they are self managing.

Of course, it never hurts to keep the habit of flying the appropriate day shapes as well... [This is enforced in some areas/countries; for our sailboat a black sphere while at anchor, and a black cone pointing down while motoring...] 

Dayshapes signal our vessel status in daylight to anyone near enough to care...

And we can always hail them on the Marine VHF radio...


Reactive measures: 

What do we do when other vessels enter our self proclaimed 'safe zone'? [e.g., A 200 ft radius Guard Zone set on the RADAR.]


Illumination and light signals:

Remember, our deck is already well illuminated and defined by the 3 deck level and an optional masthead dusk-to-dawn anchor lights...

  

The first thing we do if there is vessel traffic encroaching on our safe zone in the dark is turn on our two LED deck lights [one on each mast of our ketch...] 

We have a switch next to our berth as well as in the pilothouse and cockpit. We can also turn the deck lights on remotely with our smartphones via the remote vessel monitoring system when we have cell signals. [This is handy when returning to the boat from the dinghy, kayak, or when on a dock.]

This adds even more light to our deck, and perhaps indicates to the other vessel we know they are there...

We can also activate a 900 lumen 'back-up' light on our stern from within our sleeping cabin. [In the future, once we install the forward looking LED 'headlights' for night running, we will add the ability to activate them remotely as well.]

On the masthead there is a (SOS) strobe light which I wouldn't hesitate to activate if warranted.

We also have a variety of extremely bright, portable signaling devices, flashlights, emergency dive lights, floodlights, and long distance spotlights [all of which have rapid strobe functions, and several with automated SOS] we can use to gain the attention of another vessel in our vacinity.

In addiiton to handheld lights, we can also deploy one of our laser signaling devices [kept with our PFDs.] 

Not to mention pyrotechnic flairs...


Sound Signals:

We also have a switch in our sleeping cabin [as well as both helms] that allows us to sound the air horn [and a klaxon] if necessary should we decide a wake-up call is warranted for another vessel... [Or to alert uninvited guests on deck we are aware of their presence, which is a non-issue in our current cruising grounds— unless herons count...]

In dense fog, or if we have to anchor in a non-traditional area [e.g., an emergency requires we anchor where we are- possibly in the open location or fairway where other traffic might not expect it...] or other extenuating circumstances requiring appropriate sound signals, we broadcast the appropriate sound signal over the PA horn via our VHF radio. 

The PA is also useful for one or two-way communication, so we can speak to others if needed.  Since it is also a microphone, we can hear waves, other boats, people talking, fog horns, etc.— especially useful when motoring in poor visibility...

We can also use our very loud Storm whistles, oral blow horns, and portable compressed air horns.


And we can always hail them on the Marine VHF radio...


Conclusion:

Using these techniques and approaches, we typically sleep very well at anchor- but always with a heightened level of situational awareness.

All of these modern electronics consume so little power that we don't hesitate to avail ourselves of their charms as needed.

Of course, we don't rely solely upon electronics to keep watch- they are like any other aid to navigation; we don't count on any single one... Instead we post anchor watches during times of concern [regardless of reason] and I always check the physical world anytime I have a 'feeling' [What was that?] or am up for any other reason...

Always anchoring as if it will blow 60 kts with excellent, proven ground tackle and having a selection of trustworthy, dependable, proven electronic aids to back-up our physical monitoring enhances our levels of relaxation and comfort while at anchor. [And we are typically the only boat at anchor where we are exploring these days...]

Do you take any special measures to to help you relax while at anchor? 

Favorite Sundowner recipes included!  Please leave us a comment.


Related resources:

Denali Rose Ground Tackle Inventory
Computers, Devices and Applications we use

Comprehensive review of Anchor Alarm apps