How often you dive to see your anchor after anchoring?

[Izikalvo]

Sailing the last month and a half in the Dodecanese Greece we have been anchored in many places, since I have an anchors mania I dived in many places to see how my neighbors are anchored and to my surprise, most of the anchors were just laying there, only a few were half-buried. Not only in calm days but also with 20 or 30 knots of wind. So my question to you is: do you ever check your anchor setting depth? does it matter to you? does dropping your anchor, pulling it using 3,000 RPM is good enough?

Jeanneau 43DS Viking 10 anchor 70 m long 10 mm chain.

[GordMay]

Using a steady application of reverse thrust, most boats equipped with an inboard engine, can test their anchors holding ability up to about 30 to 40 knots of wind load, assuming that the anchor employs a long snubber to absorb some of the shock loads.
I’ve read that, you get about 22 pounds of force (on the anchor) per engine horsepower, when reversing.

This suggests that a 35 Ft sailboat might need an approximately 41 HP engine to simulate a 40Kt blow (±900 lb. force, not including surge loads or gusts) in reverse.

Rule of thumb for surge loads:
In moderate protection from seas, double the wind load.
In little or no protection from seas, double the wind load, then add 50 percent more.

Commander Bob has a good anchoring guide, “Anchor Right to Stay Put”, with an excellent section describing backing down technique.
➥ Anchor Right to Stay Put

[Panope]

Originally Posted by GordMay

..........I’ve read that, you get about 22 pounds of force (on the anchor) per engine horsepower, when reversing..........

Gord,

That is very close to what I measured when using a 3 blade, feathering Maxprop (in reverse)

However, when using a 3 blade fixed propeller, I measured about 1/2 that force/horsepower (in reverse).

Steve

[rslifkin]

Available thrust in reverse will depend significantly on prop design. Some produce thrust quite effectively in reverse, others produce far less thrust in reverse than forward.

Personally, I figure if the anchor holds a decent bit of reverse thrust, it'll hold in actual wind and I don't really have a reason to care what it looks like down there. Typically I test with both engines at 1000 rpm in reverse, which seems to produce at least as much rode tension as a 30 kt wind gust. If the RPM sounds low, it's a function of having much more power than a typical sailboat. So with a pair of 340hp engines spinning 22" diameter props, 1000 RPM is a good bit of thrust (enough to move the boat a little over 5.5 kts in forward).

[Nicholson58]

All of this goes out the window for larger boats. We weigh 40 tons. Our prop is 24 inch, 3 blade variable pitch controlled. 115 HP. I can do serious damage using standard backing down procedures. I’m sure naval vessels do not do this either. At a certain point, other methods are appropriate. We drop the hook, #121 Rocna, and set the measured chain scope as we drift back. When the boat hits the end of the slack there is a large hit as the chain runs rod straight and drives the anchor in. We set the Watchmate anchor watch at the drop point and follow the distance from the set over the following hours. BTW, we only run to 1200 engine rpm max with 2:1 reduction.

In the Caribbean the water is usually clear enough to check the set. We’ve also learned which harbors have good setting and where we need to pay more attention. Ask if you plan to go.

[Mike OReilly]

Where I have mostly cruised, no one jumps in for a casual swim. Sometimes I can see my anchor from above, but mostly I have no direct idea what it looks like down there. That said, I am confident of my anchoring technique, which has been put to the test up to hurricane (Cat I) strengths, but routinely sees gale and storm level tests.

Process involves picking an appropriate site, carefully lowering and paying out rode. Slowly setting, then digging in the anchor. Eventually culminating with a solid hold for minutes at full cruising thrust (~2000 RPM, 3-blade fixed prop).

But all of this is an excellent argument for using the largest new-gen anchor one can reasonable manage .

[Allied39]

It was pointed out to me lately on a classifieds advert that CQR's do not work and are worthless....literally.
So , with that logic your question would be moot.
I however use a CQR, and dive pretty much any time I am in water clear enough to see.
Excellent practice with no downside....except perhaps for the lack of excitememnt when we don't drag.

Just voicing my opinion ( which is great for the novices I am informed) but do not wish to engage those who disagree and obviously I dont feel like dealing with the trolls.

[Mike OReilly]

Originally Posted by Allied39

It was pointed out to me lately on a classifieds advert that CQR's do not work and are worthless....literally.
So , with that logic your question would be moot.
I however use a CQR, and dive pretty much any time I am in water clear enough to see.
Excellent practice with no downside....except perhaps for the lack of excitememnt when we don't drag.

Just voicing my opinion ( which is great for the novices I am informed) but do not wish to engage those who disagree and obviously I dont feel like dealing with the trolls.

I hope this wasn't a response to my post Allied. Anyone who says a CQR doesn't work is not living in reality. They just don't work as well as the newer anchors. Doesn't mean they don't, or can't, work just fine.

They're certainly not valuless. I sold my "Genuine CQR" (45#) for $300 after I upgraded. But I would never suggest anyone buy a new CQR these days ... not when there are better options for similar prices.

[fatherchronica]

We have 2 Lexan windows in the bottom of our dinghy that almost always afforded us a good view of our anchor. We would cruise over it almost every time we left the boat..

[rslifkin]

Originally Posted by Nicholson58

All of this goes out the window for larger boats. We weigh 40 tons. Our prop is 24 inch, 3 blade variable pitch controlled. 115 HP. I can do serious damage using standard backing down procedures. I’m sure naval vessels do not do this either. At a certain point, other methods are appropriate. We drop the hook, #121 Rocna, and set the measured chain scope as we drift back. When the boat hits the end of the slack there is a large hit as the chain runs rod straight and drives the anchor in. We set the Watchmate anchor watch at the drop point and follow the distance from the set over the following hours. BTW, we only run to 1200 engine rpm max with 2:1 reduction.

In the Caribbean the water is usually clear enough to check the set. We’ve also learned which harbors have good setting and where we need to pay more attention. Ask if you plan to go.

This is a good point. On larger boats with more power, a bit more care is required to avoid doing damage. My boat is only 26,000 lbs loaded, so as long as I'm somewhat careful, the initial takeup and set isn't too harsh. But applying anything more than a small bit of throttle in reverse is asking to damage things, as much like you, I've got lots of power on tap, fairly deep reduction gears (2.57:1) and 2 decent size props (22x25). And slack definitely has to be taken up before applying power in reverse.

[SV__Grace]

in many places to see how my neighbors are anchored and to my surprise, most of the anchors were just laying there, only a few were half-buried. Not only in calm days but also with 20 or 30 knots of wind.

This doesn't surprise me. I like to watch new arrivals that anchor near me and what DOES surprise me is how many just drop their anchor and some rode and don't back down.

Trying to keep an open mind, maybe they're braver and smarter than I am as an anchor will dig in if the boat moves back in wind/tide as it's designed to do, and the weight of the anchor and chain can be enough without the anchor set.

Example- When my anchor is set in one direction for a day or two in mud, the chain gets buried enough that it can take 20+ knots of wind to free it from the bottom to fully swing the other way.

So maybe they're to be admired?!

[grandmaR]

We almost never dive on the anchor.



When we anchor in the Chesapeake where a lot of the bottom is soft mud and where the water is often too murky to see your hand at the end of your arm, we would never dive on the anchor. But holding is usually very good.


When we anchor where the water is clear enough to see the anchor we can look without diving.



When we anchor at dusk or after dark, we would never dive on the anchor.

[Dsanduril]

Originally Posted by Mike OReilly

I hope this wasn't a response to my post Allied. Anyone who says a CQR doesn't work is not living in reality. They just don't work as well as the newer anchors. Doesn't mean they don't, or can't, work just fine.

They're certainly not valuless. I sold my "Genuine CQR" (45#) for $300 after I upgraded. But I would never suggest anyone buy a new CQR these days ... not when there are better options for similar prices.

Mike, thanks for the balanced post on CQRs, too rare around here. A lot of people have spent an awful lot of nights (yours truly included) sitting comfortably at anchor behind a CQR. Now I have something with a roll bar...

When in warmish water I nearly always dive the anchor (regardless of make) just to see what I ended up with. It is entirely possible to pull hard in reverse, dive, and find that just the very tip of the anchor is hooked on a nice rock ledge, any swing will pull it out with the wind from a baby's breath.

Here in the cold climate, with the water visibility of 3' (1m) or less I just trust to my anchoring and backing technique (and the Watchmate anchor alarm - although it can be quite annoying when you lose GPS signal in a fjord).

[barnakiel]

When it is warm water and clear / clean water, I will dive on our anchor.


Teaches me lessons.


One lesson: your anchor is 50% buried on its side rather than shank up ...


b.

[EmeraldCoastSailor]

I only dive on anchor if I happen to be swimming or cleaning hull. I don't dive on it as part of regular anchor process but if I plan to spend the night, I do gradually back down meaningfully to make sure it is set. I do like my 44# Rocna on my little 35' sloop.