Aargghh - Why won't my boat hold on the anchor?

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Aargghh - Why won\'t my boat hold on the anchor?

I think I either need some good advice on anchoring skills or a new anchor!

Today was the final straw, I was sat at the Cawsand Bay Hotel enjoying the weather, the beer the food, when I suddenly realised my boat had drifted approximately 300yards from its original position. I retuned to the boat after a speedy row agsinst the wind and tried to anchor a further 3 times before it finally held. This whilst my beer was going warm and my food going cold!

This is not the first time this has happened and its come to a point where I can't relax whilst ashore.

My method involves letting the anchor out with a surplus of chain, reversing and feeling the chain until I feel it grip, although this is obviously not enough.

The boat is a SeaRay 260 with the standard Delta anchor.

Any suggestions?? /forums/images/graemlins/confused.gif
 
Re: Aargghh - Why won\'t my boat hold on the anchor?

I thought I might get asked that so Im just sorting through my handbook now to find the speciifcation. I have about 30m of chain.
 
Re: Aargghh - Why won\'t my boat hold on the anchor?

Can't find the weight but its quite big and operated by an electric windlass! Its certainly the largest that could fit in the chute. The chain I know is bigger than 8mm and i tend to anchor in no more than 6m of water but normally about 4m.
 
Re: Aargghh - Why won\'t my boat hold on the anchor?

My guess is you are not using enough scope of chain, try the following.

Supposing your anchor is the correct weight for the boat and a sensible design for the sea bed you are achoring in you will need to deploy 4 times the depth of water with all chain or 6 times the depth of water with rope and chain. Set the anchor with the bow facing into the wind or tide whichever is strongest and motor astern slightly to set the anchor as you lower it and check it is fast by finding a couple of fixed objects ashore that are inline (in transit) and monitor them for a while before switching off the engines, to check for drift.

Only then is it a good idea to leave your boat!!
 
Re: Aargghh - Why won\'t my boat hold on the anchor?

Sound like your equipment is ok as is your technique, so I question the sea bed. If there is weed you stand no chance. Try and find a clear bit of sand or mud and I think you will have no problems.
 
Re: Aargghh - Why won\'t my boat hold on the anchor?

This is sort of what I do - In fact today I made a cup of coffee before I set off! Maybe its the length of chain in question, but as I watch everone else they just seem to lob theirs overboard and forget.

Is my type of anchor only any good in sand or mud, as where I anchor tends to be weedy and gravelly?
 
Re: Aargghh - Why won\'t my boat hold on the anchor?

Thanks DavidJ - Seems like I posted the same time, however like I say, everone else just seems to stick fast!
 
Re: Aargghh - Why won\'t my boat hold on the anchor?

IMHO, you should check with your insurance co whether your policy permits you to leave your boat unattended at anchor because it is a bit of a grey area. The Delta is a good all purpose anchor but you should check HERE that yours is correctly sized or even consider upgrading it
You should not have a prob dragging in reasonable conditions if you've put down at least 3 x max depth of chain and your anchor is right for the boat. As David J has already said, best not to drop it in weed though
 
Re: Aargghh - Why won\'t my boat hold on the anchor?

Delta anchors have a pretty good reputation really,

In relatively shallow water you should take into account the height of the bow roller above the water surface and include it in the water depth when calculating how much scope to let out.

If you are say anchoring in 4m of water, and the bow roller is say 1.5 m. above the water, then you should let out about 22m. of chain, not just 16 m.
16 m of chain in what is effectively 5.5m water depth is a tad under 1:3 scope. It might just make a difference.
 
Re: Aargghh - Why won\'t my boat hold on the anchor?

Well the insurance thing is why I can't relax when away from it as it isn't covered when at anchor and unattended!

Thanks for the link Deleted User, but that just confirms I do have the correct weight.

Ok - I have a few ideas from all your kind replies so I'll perservere a little longer with your thoughts in mind and see how I get on.
 
Re: Aargghh - Why won\'t my boat hold on the anchor?

I've anchored in Cawsands dozens of times, never had a problem. Plow anchor 35lb and 8mm chain, much bigger boat though. Get facing same way as other anchored boats, drop anchor till it's got to the bottom with some spare chain, then back up slowly, as you let the chain out, hopefully in a long line. Best to guess to much chain than to little, add some for hieght of bows. I mark my chain every ten metres, so a bit of an idea whats out.
 
Re: Aargghh - Why won\'t my boat hold on the anchor?

Good point made about the height of the bow above the water, never thought of that /forums/images/graemlins/blush.gif
 
Re: Aargghh - Why won\'t my boat hold on the anchor?

This is what i cant understand. Like I said, everyone else seems to fix fast and I just keep moving out of position. Later in the day, we went over to the north side between Kingsand and Portwrinkle, where I know its sandy, and I still had to fire up the engines to reposition as we drifted past an adjacent yacht.
 
Re: Aargghh - Why won\'t my boat hold on the anchor?

The lighter delta anchors are sometimes dodgy in weed. From memory Cawsand is that very fine gravel though, which the Delta should work very well in. How strong was the wind/tide on the day it slipped? I suppose if I was leaving the boat in 4m to go to a restaurant I'd put the whole 30m in. I'd be amazed if it dragged with that, in say F5 or less. Doesn't sound like you're doing anything wrong; just unlucky and got some hard carpety weed
 
Re: Aargghh - Why won\'t my boat hold on the anchor?

Well to be honest, I just sort of dump some chain down and back up a bit. Theres not alot of science to it. But it's not the anchor that holds you, it's the weight and length of chain.
 
Re: Aargghh - Why won\'t my boat hold on the anchor?

Most of the time, yes, but the anchor stops the chain from moving when it gets tugged if it's bouncey or blowey.

...else why bother with an anchor?
 
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