You are setting your anchors badly and then blaming the anchors

[AngeW]

Removing duplicate post

[boatman61]

I have never blamed any of my Bruce's... for anything..

[noelex 77]

I did a quick experiment.

Unfortunately there is very little wind at the moment so letting out the rode would not achieve much, but I did a test with a Garmin 62 HH which probably has the best GPS chip of all my units. Its screen is not big enough to work as a plotter, but nicely it reports the distance to a waypoint in meters (why don't all GPS units do this?). Making the anchor the waypoint and moving the GPS back along the deck in 1m increments I got the following result:

Starting point 23-24m
1m back 24m
2m back 25m
3m back. 26-27m
4m back 27m
Back to the start point 24m

This is much better and steadier than I expected. Kudos to Dockhead . The accuracy to match the results with transits with a modern GPS chip and satellite differential signal does seem achievable especially as the track on a real plotter would allow the eye to eliminate some of the more anomalous readings.

That is the great thing about this forum. There is always something to learn. I expected transits to be able to beat the GPS quite comfortably and that does not seem to be the case.

[noelex 77]

Originally Posted by Dockhead

They only cost $199 in the U.S. I can bring you one back from the States in August if you want one.

Thanks for the offer.
This is one of the new 10hz GPS units. These units do much better with current calculations so are popular with the keen racing crowd. Unfortunately only one of my plotters will accept a NMEA 2000 input so I have been delaying this sort of upgrade until the next revamp of my electronics which I am hoping is some time away. New boat ?


Crusing sailors seem very ambivalent about the quality of their GPS fix, often accepting an antennae position, that is suboptimal, or not engaging a satellite differential fix when this is possible (some of the older units need some fiddling).

In my view the GPS is a very important navigational tool and if we can get better accuracy and/or precision it is worth doing so. As this example of using it set the anchor shows there are times when precision of only a metre or so is beneficial if it can be achieved.

It is not clear if the higher processing speed of these 10hz units helps this, together with ability to use the Russan system, but I suspect it does.

[Dockhead]

Originally Posted by noelex 77

I did a quick experiment.

Unfortunately there is very little wind at the moment so letting out the rode would not achieve much, but I did a test with a Garmin 62 HH which probably has the best GPS chip of all my units. Its screen is not big enough to work as a plotter, but nicely it reports the distance to a waypoint in meters (why don't all GPS units do this?). Making the anchor the waypoint and moving the GPS back along the deck in 1m increments I got the following result:

Starting point 23-24m
1m back 24m
2m back 25m
3m back. 26-27m
4m back 27m
Back to the start point 24m

This is much better and steadier than I expected. Kudos to Dockhead . The accuracy to match the results with transits with a modern GPS chip and satellite differential signal does seem achievable especially as the track on a real plotter would allow the eye to eliminate some of the more anomalous readings.

That is the great thing about this forum. There is always something to learn. I expected transits to be able to beat the GPS quite comfortably and that does not seem to be the case.

Bravo!

One thing to keep in mind is that EPE tells you the theoretical error compared to earth. Not indeed, the random error between different position fixes. The consistency between fixes will be much higher than absolute error compared to earth. And it's the consistency between fixes which determines how well the GPS fulfills this purpose.

[tomfl]

Originally Posted by AngeW

SNIP

We apply the full engine test before putting on the bridle

SNIP

Wondering about how others do this.

I normally take at least half an hour to anchor. Pick a spot, approach it with nose into the wind, drop the anchor, let out enough chain to get it to the bottom and a little more, watch how the boat swings, let out chain in increments equal to the depth of the water (in my case around ten feet for my three foot five inch draft catamaran that I try to anchor in 10-12 feet in Florida Keys), watching how the boat swings with each let out of chain, once I get to 5-7 to one ratio I walk around the boat and look for waypoints, rest my tired old arms, and look some more,

then I attach the bridle and back down,

turn on Drag Q ueen, look at the GPS, walk around the boat again and try to get good bearings and estimate swing due to wind and current interaction, and if I am satisfied I turn off the engines, and finally spend at least half an hour just watching things, then I raise the outboard engines in the wells and hope for the best.

So do you guys back down before or after you attach the bridle?

[Dockhead]

Originally Posted by tomfl

Wondering about how others do this.

I normally take at least half an hour to anchor. Pick a spot, approach it with nose into the wind, drop the anchor, let out enough chain to get it to the bottom and a little more, watch how the boat swings, let out chain in increments equal to the depth of the water (in my case around ten feet for my three foot five inch draft catamaran that I try to anchor in 10-12 feet in Florida Keys), watching how the boat swings with each let out of chain, once I get to 5-7 to one ratio I walk around the boat and look for waypoints, rest my tired old arms, and look some more,

then I attach the bridle and back down,

turn on Drag Q ueen, look at the GPS, walk around the boat again and try to get good bearings and estimate swing due to wind and current interaction, and if I am satisfied I turn off the engines, and finally spend at least half an hour just watching things, then I raise the outboard engines in the wells and hope for the best.

So do you guys back down before or after you attach the bridle?

I would not, personally, put on a snubber or bridle until just before cocktail time. Why would you do a hard backdown on a bit of nylon which is much less strong than your chain?

Don't forget to belay the chain every time before putting any stress on the rode.

[Robin3]

Originally Posted by AngeW

Wonder how long before we can add a gps or transmitter to the actual anchor.

you mean you don't have one yet? How Quaint!

[Robin3]

Originally Posted by Skeeko

Best thing I ever did was own a boat with a lousy anchor for a few years. I learned so much more about anchoring with that piece of junk than I ever did with well equipped boat. There is nothing like holding the rode on a small boat and "feeling" the bottom as the anchor skips along to let you know what a real hold is like. I always slept soundly (minus the few hard blows) but I did give a few hard tugs before being convinced it was set.

I see boaters that drop the anchor and forget about it. They simply don't know what they don't know. But I do since I check out their anchors while swimming. At one anchorage in St. Lucia I saw 9 out 10 anchors on their sides. Ignorance is bliss.

. I had a pretty crap selection of anchors on my first few boats, mostly either copy CQR ploughs or copy Danforths, even an old fisherman (anchor not angler) In those days marinas in the UK were few, far between and unaffordable and weather information much less accurate or easy to obtain. you learned self reliance quite fast back then, compared to nowadays when, if an anchor doesn't set in the first 6 inches, then a new one is purchased and another anchor thread begins... Backng down on the anchor in my earlier days was via a backed mainsail, as a 4hp two stroke Stuart Turner inboard with a carboned up exhaust didn't have much grunt even if it started.

[boatman61]

Originally Posted by Robin3

. I had a pretty crap selection of anchors on my first few boats, mostly either copy CQR ploughs or copy Danforths, even an old fisherman (anchor not angler) In those days marinas in the UK were few, far between and unaffordable and weather information much less accurate or easy to obtain. you learned self reliance quite fast back then, compared to nowadays when, if an anchor doesn't set in the first 6 inches, then a new one is purchased and another anchor thread begins... Backng down on the anchor in my earlier days was via a backed mainsail, as a 4hp two stroke Stuart Turner inboard with a carboned up exhaust didn't have much grunt even if it started.

Shoulda tried it with a Seagull..

[Dockhead]

Originally Posted by Robin3

. I had a pretty crap selection of anchors on my first few boats, mostly either copy CQR ploughs or copy Danforths, even an old fisherman (anchor not angler) In those days marinas in the UK were few, far between and unaffordable and weather information much less accurate or easy to obtain. you learned self reliance quite fast back then, compared to nowadays when, if an anchor doesn't set in the first 6 inches, then a new one is purchased and another anchor thread begins... Backng down on the anchor in my earlier days was via a backed mainsail, as a 4hp two stroke Stuart Turner inboard with a carboned up exhaust didn't have much grunt even if it started.

School of CQR, eh? I'm a graduate of that one myself; probably have lifelong sleep disorders as a result

[tomfl]

Originally Posted by Dockhead

I would not, personally, put on a snubber or bridle until just before cocktail time. Why would you do a hard backdown on a bit of nylon which is much less strong than your chain?

Don't forget to belay the chain every time before putting any stress on the rode.

If my bridle can't handle the stress of a backdown I need a new bridle.

Not sure how much experience you have anchoring a multihull, as opposed to a monohull, but it is fairly standard to put on a bridle as soon as you are happy with the anchor set. I have not seen anyone but you advise to wait to put on the bridle and wonder what your reason(s) are.

Catamarans tend to sail at anchor, especially if there is any current at all. A trimaran is even more likely to sail at anchor since the amas (with a small number of exceptions) are a few feet aft of the bow of the main hull. A bridle can reduce the chance a multihull will sail at anchor. Sailing at anchor tends to degrade how well an anchor is set.

If there is any seaway there is also a possibility of pounding, something that can be mitigated by adjusting the length of one side of the bridle to change the angle the waves hit the bow. Pounding can also degrade the anchor set.

As a rule the light is better when I first set the anchor as opposed to later on when the sun may have set and since I don't see as well in the dark as I do when it is light this is another reason I like to put the bridle on earlier.

Bottom line for me is there seems to be no down side to putting the bridle on early, only upside.

But I could be wrong.

[Robin3]

Originally Posted by boatman61

Shoulda tried it with a Seagull..

I haa colection of Seagulls too, they were actually made just up the road from where I lived back then and a club mate even worked on the production line. I had a recoil starter add-on for mine but it still didn't 'do' reverse, let lone against a well set CQR knock-off

[Dockhead]

Originally Posted by tomfl

If my bridle can't handle the stress of a backdown I need a new bridle.

Not sure how much experience you have anchoring a multihull, as opposed to a monohull, but it is fairly standard to put on a bridle as soon as you are happy with the anchor set. I have not seen anyone but you advise to wait to put on the bridle and wonder what your reason(s) are.

Catamarans tend to sail at anchor, especially if there is any current at all. A trimaran is even more likely to sail at anchor since the amas (with a small number of exceptions) are a few feet aft of the bow of the main hull. A bridle can reduce the chance a multihull will sail at anchor. Sailing at anchor tends to degrade how well an anchor is set.

If there is any seaway there is also a possibility of pounding, something that can be mitigated by adjusting the length of one side of the bridle to change the angle the waves hit the bow. Pounding can also degrade the anchor set.

As a rule the light is better when I first set the anchor as opposed to later on when the sun may have set and since I don't see as well in the dark as I do when it is light this is another reason I like to put the bridle on earlier.

Bottom line for me is there seems to be no down side to putting the bridle on early, only upside.

But I could be wrong.

I have little experience with cats, so defer to your knowledge, of course.

My remarks assumed that the bridle on a cat has the same function as the snubber on a mono; if that is not the case, then please ignore my previous remarks.

You would not want to put on a snubber early, because it is, by design, much weaker than the main anchor rode. It's made to stretch, and you will accelerate its wear by stretching it out during your backing down process.

This remark does not apply if your bridles are stronger than that, or if you have some other reason to have it on before backing down. On monos, we really usually don't have any good reason.


Another thing to keep in mind is that most people prefer to do their anchor setting prior to putting out final amount of scope. They usually set the anchor with 3:1 out or so. I am not actually sure why this is correct; I do it only because I was taught that way. Maybe with less scope out, you are pulling more directly on the anchor which helps it set better. Then after you are happy with the set, you let out more chain, then do your final, maximum power test pull. Then you put on the snubber and have a drink. At least, that's the way I do it; I'm sure there are plenty of other valid ways to do it.

[colemj]

Originally Posted by tomfl

So do you guys back down before or after you attach the bridle?

We back down before attaching the bridle for the simple reason that if we don't like the set or placing, it is less work to start again. We have a chain stop right at the roller for backing down.

The bridle then goes on straight away - no waiting until cocktail hour (unless cocktail hour happens to be immediately after setting the anchor)

Mark