Backing down on anchor

L

Larry Patrick

New member
Few weeks ago we stayed at anchor,windfinder predicted light winds. After work we got there hour before dark. Arrived at area we wanted to stay ,waterfall and train tracks 20 minutes before dark. Manson Supreme 25# dropped anchor backed up felt it snug,then when trying to set it it would come lose. Wondering if with a 150 hp outboard will you pull anchor every time if you back down too hard? Never felt real snug, so after 6 attempts,just snugged it up and figured it would be okay? Carried Fortress up front tossed that with chain and rode at different angle. Had drag queen app on I-Pad think 30 or 50 ft, alarm went off after an hour in bed. Changed it to I think 100ft. First hour in bed we were rocking quite a bit,then as predicted winds went down to nothing. Realized in morning that noise was chain rubbing hull ,let more out so just rode would be against boat. In morning from calm night and wind picking up from different direction in morning had 2 chains tangled,not much fun lifting 2 chains and anchors until I got the mess untangled. So lesson learned was should have put 1 anchor out. Also need more time to find better bottom conditions cant get there right before dark. If winds would have picked up not sure anchor would have held? Looking at shore there was a lot of cliffs ,so maybe the bottom isn't best for anchoring. Just wondering how much throttle to bury anchor and im guessing whatever bottom is like you will pull anchor with too much throttle? Curious as to future trips when do you feel anchor is set enough for the night? After all season tying up at dock this was a different ball game, What max wind speed will you anchor out at when watching forecast?
 
Larry, I don't know what length of chain you have ahead of your rode - but you mention that it was rubbing the hull. Just wondering if you had enough scope? If you have the room and the rode - let it out.

As for dragging the anchor in reverse, don't forget that most props have substantially less thrust in reverse as compared to forward. I would think that a 25pd. anchor set with chain and enough scope in good holding bottom conditions should not be that easily dragged by your boat in reverse.

Regards, Rob
 
As you mention, there are a lot of variables. Oftentimes (especially if I think the bottom may be a bit "tricky") I'll let the anchor sit and settle a bit before I back down. Maybe 30 minutes or so (I never leave the boat right away anyway when anchoring).

I've never backed down with 150 hp, but did customarily back down with around 30hp diesel with big prop. We let 'er have it, watching "set points" on the shore to see if we were moving while doing so (shouldn't happen once the chain is streched to full length). I do the same with the 80hp on the 22. If it slowly moves backward as I do so, I re-set.

Once set I put on a snubber, especially if you have all chain out. Something like 50' of nylon so it has some give.

I don't like to anchor with fair weather in mind (because that's always when a storm comes through at 3:00 a.m.). Not that I do a hurricane setup every night, but I like to basically set for a medium blow every time.

Oh, I also don't back down on a windlass, but rather tie off to a cleat or etc. so as not to put the strain on the gipsy, etc.
 
I think a 150 can always pull an anchor loose if you try hard enough. Try this:
Go to the bow and have your crew lower the anchor to approximately the depth under the anchor (anchor is now hanging very near the bottom) Then lower the anchor as the boat is put in reverse. The chain is now being laid out on the bottom as you reverse. After releasing about 5 times the depth of rode, stop the windlass. Put your hand on the rode and resume reversing. You will feel the rode tighten and become very taut. If you feel a chattering from the rode, it is skipping on the bottom. Let out more rode and retry. When the rode becomes very taut, select neutral. as the boat comes to a stop, if you feel no chattering or skipping, it's stuck. Sleep well!
 
Lets start out: First you scout the area you are going to put the anchor down in. Run over it with the boat, and look at the depth finder--see what the bottom type is: Any snags, rocks, piles of brush structure? How about logs, kelp?

Look at the chart.

Lower the anchor slowly to the bottom, and start gradual sternway, as you pay out the rode. If the chain was hitting the boat--most likely you did not have enough out. You want the depth of the water plus the height of the bow from the surface as a base. Then multiply this x 3 before you put any tension on the line.

Lets say, you are in 20 feet of eater, and then 3' off the water--or 23 x 3 = 69 feet of line out before you put any tension on the rode. Feel it by hand, and see if the anchor seems to be catching. Often the anchor has to sit for a few minutes. If it seems to be holding, then give a good pull on it by hand. Slowly back down paying line out until you are at the 7:1 (in this case this would be 7 x 23 or 161 feet! (that is why you want the anchor line marked at each 50 feet.

After you are at the 7:1, then tie the rode to the for deck cleat, and give slow reverse--slow!. You can gradually increase it if the anchoris not dragging. How do you know if the anchor is dragging? First the rode comes tight--and most of us can recognize the 7:1 scope from experience. If the rope comes tight and goes slack again--draging. Take sights on two objects on shore, and see if the relative distance moves. As a last resort....you can always watch your chart plotter or i pad. (I am still old fashioned--and use the ranges).

As for power--I generally give gradual power--generally not full power.

If you want to put out a second anchor (which I often do), I will come up on the primary anchor until I am over it, then veer the boat off to one side, and drop the second anchor 50 or so feet to the side. Or I may take the second anchor out with the dinghy. NEVER throw an anchor! There is a good possibility that you can foul the flukes and then that anchor may not set.

I have had a number of instances, where I was not sure the first anchor set, so I set out a second anchor--then in the morning, found that in fact the first anchor has set well.

The windlass is convient, it saves your back. But as Sunbeam said, it is not to take the load of anchoring. Snubbers after your anchor is set if needed.

As to HP, and full throttle in reverse--it is rare that I do that. Both of my large sailboats (46 and 62 feet) had 90 hp diesel engines, and 24" to 26" props with 3:1 reduction greats. I would give about half throttle. On my trawler with over 400 hip--I would only give about1/3 throttle in reverse.

I have held in winds of excess of 90 knots a number of times. Once in a know 130 knot, (that was in a protected area, and several anchors).

At Lake Powell last month, we had gusts of over 50 knots on the beam, and no dragging, with a 10 lb boas, and 6 lb Fortress.
 
Thanks a lot of good information, guess setting an anchor well is a learned skill. I was in about 12ft of water left 50ft of chain out,was using the windlass when setting and left a few links of chain in windlass, wont be doing that anymore. Will be adding a snuber ,didn't have one. Never thought about moving up on set anchor and putting second anchor 50 ft away good to know. Next season will add all suggestions to my anchoring. I was dropping chain straight down before backing,will also be tying off to bow and using snuber. That was first time trying to set for an overnight,other times it was just swimming off boat.
 
Sounds like you've soaked in the info. You're right in that it is a learned skill: some base knowledge and then practice. I had it easy in that my first 400 or so times I was crewing for an experienced sailor. (But it didn't take that long to get the gist.)

As Thataway said, the first important thing is to choose your spot. In addition to pre-research (charts, etc.), I like to always make a pass through the proposed anchorage, watching both outside with the eyeballs, and the depth sounder. Then come back around a second time and anchor. Also, if things don't seem right after you have anchored, pull things up and do it again (there is where a powered windlass is especially nice).

Also the part Thataway said about paying out the rode gradually, so it doesn't dump in a heap, and putting on power gradually when backing down. I forgot to say those.

I love to spend nights at anchor. Sure, there is always "mind attention" at some level throughout the night, but it's so nice to have the boat riding "free" (as compared to being tied up at a dock). It's extra nice in warm weather as the wind will usually come in the forehatch (boat generally rides head to wind).
 
Sunbeam always wanted to have tried sailing ,but didn't grow up around it. We also realized how much more enjoyable that night was at anchor. Too bad it was right at end of season ,instead of squeezed in at dock , you get to enjoy loons crying ,other wildlife ,trains going by, sound of waterfalls ect. Look forward to next season and overnighting at anchor away from the dock.
 
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