Danforth Q's

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Inselaffe

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Danforth Q\'s

Marnin,

I am starting to find my way around anchoring.

My (~1.5t) Etap 22 came with an approx 9kg Danforth style anchor:

Anchor.jpg


The flukes(?) seem to be much nearer the length of the shank(?) than all the others that I have seen, and of the 7kg Danforth type that I recently got for a second anchor.

Is this 'normal', and is it possible to say if it will affect setting and holding?

I ask because I have had problems getting it to set on my first few tries, it seems to drag when I put motor half astern.

95% probable that it is because I am doing something wrong but from what I have heard/read what I did wasnt far off:
the last attempt as an eg (sand):
I lowered to bottom paying out 7:1 scope line with 6m chain leader as drifted with breeze downwind, snubbed and then motor half astern to set.

But I had to stop with the motor because it was dragging the anchor.
It held me overnight, but in sheltered non-tidal 'lake' behind a lock with only F3. If it hadn't have held, I would have just drifted to the nearby bank, no danger.

It was so much better than being rafted up on one of the island harbours, I loved it!

Next I want to try in the tidal channels behind the islands, but its with strong reversing currrent and I want to be much more confident before I try, so I thought I could (tentatively!) ask here first if it could be an obvious issue with my anchor...
 
Re: Danforth Q\'s

Hi,
The flukes on the genuine Danforth are approx. 70% of the length of the shank, never more. It is difficult to say how a change in this ratio would effect the holding capability, but I would be concerned if the ratio were very different. I don't like the Danforth in hard sand, it tends to skid over the bottom. It is a much better anchor in mud. You might want to try something else, such as a Delta. I'm quite sure Craig will be along in a little while to give information on the Rocna, with which I have no experience. There is an article on anchoring and a size selection chart on my website under Cruising Resources. ( I don't sell anchors or anchoring gear.)
 
Re: Danforth Q\'s

Thanks,

The following quote from your website was interesting to me 'Apply some engine power, about half revs should do, to set the anchor and stretch out the rode. The anchor will continue to bury over time as the current action and the boats motion worry away at it. Applying full power at this stage will just drag your anchor along the bottom, unless you have a particularly puny power plant.'

Although I really dont know what I'm doing yet, I had also thought that this 'half revs' must just be a rule of thumb and would depend on the motor. On my little boat I have a 9.9HP 4stroke with a high thrust prop. If I get anywhere near third revs motoring (in flat sea & little wind) the prop ventilates/cavitates because I am reaching hull speed (even when totally clean), so maybe I am trying to set the anchor with the motor too aggressively?

I guess knowing exactly how much astern is enough will only come with experience?
 
Re: Danforth Q\'s

Yes, it is difficult to give a precise answer to the question of how much power should be applied to digging the hook in. You certainly need to pull the rode straight so that you are applying horizontal pull on the anchor. Unfortunately, too much power and you just do a bit of ploughing! It will, as you say, come with experience.
 
Re: Danforth Q\'s

different point but have you considered re proping your engine to both run easier and give you an overall better gearing?

it will not make much difference to fuel consumption to be running at slightly higher revs for the same speed.

wouldn't bother for a few hundred revs but the example you quote is extreme and won't be pleasing the engine at all!
 
Re: Danforth Q\'s

[ QUOTE ]
The following quote from your website was interesting to me 'Apply some engine power, about half revs should do, to set the anchor and stretch out the rode. The anchor will continue to bury over time as the current action and the boats motion worry away at it. Applying full power at this stage will just drag your anchor along the bottom, unless you have a particularly puny power plant.'

Although I really dont know what I'm doing yet, I had also thought that this 'half revs' must just be a rule of thumb and would depend on the motor. On my little boat I have a 9.9HP 4stroke with a high thrust prop. If I get anywhere near third revs motoring (in flat sea & little wind) the prop ventilates/cavitates because I am reaching hull speed (even when totally clean), so maybe I am trying to set the anchor with the motor too aggressively?

I guess knowing exactly how much astern is enough will only come with experience?

[/ QUOTE ]If your anchor is dragging under full power in reverse, it either isn't set properly or you need a new anchor. Most boats, especially sailboats, can't simulate anything like bad conditions using their engines and props. (Tugboats excluded).

Your prop sounds okay - when setting the anchor you're concerned with bollard pull, not that it starts cavitating at a certain speed.

Sometimes the anchor will take a while to set - don't just dump it on the bottom then open up the throttle in reverse. Wait for it to "bite", then slowly increase the power.

[ QUOTE ]
Yes, it is difficult to give a precise answer to the question of how much power should be applied to digging the hook in. You certainly need to pull the rode straight so that you are applying horizontal pull on the anchor. Unfortunately, too much power and you just do a bit of ploughing! It will, as you say, come with experience.

[/ QUOTE ]/forums/images/graemlins/confused.gif
If you pull the rode straight, you're no longer applying horizontal pull... there is a vertical component to it (unless your anchor is up on dry land at an altitude level with your bow roller /forums/images/graemlins/crazy.gif) and it is at this point that you will know whether your anchor will hold - or pop straight out. Best to test it if you can!
And re the ploughing, see above.
 
Re: Danforth Q\'s

I told you Craig would be along in a little while! Obviously I was not suggesting you pull to the point where your rode is straight from the bow to the anchor!! I meant, as I'm sure you realize, you should straighten your rode out on the seabed so you are pulling on the anchor, not just untangling your rode.
 
Re: Danforth Q\'s

After my experience at the w/e I can confirm that matching anchor type to seabed is important.

My normal anchor is a Delta and holds me in a F6 on sand without any problem, but using it in soft mud near Cleavel Pt in Poole with a F5 and a current running I dragged twice.

I replaced the Delta with my largish (40kg) Danforth and it held no problem.

Looking at the picture of the Danforth, the shank does look rather short and Inselaffe doesn't say how much and type of rode he had deployed.
 
Re: Danforth Q\'s

That Delta and Danforth combination is quite useful, covering sand and mud.
Inselaffe says he had 7:1 down and with 6m of chain leader, so I didn't think that was an issue in this case.
 
Re: Danforth Q\'s

[ QUOTE ]
My normal anchor is a Delta and holds me in a F6 on sand without any problem, but using it in soft mud near Cleavel Pt in Poole with a F5 and a current running I dragged twice

[/ QUOTE ] funnily enough I have experienced the same thing in the same place with a delta, whilst my Bruce seemed to get into a harder lower layer and hold firm. Early indications with the new Sword I am trying are that it works even better coming up hard and fast........early days yet though.
 
Re: Danforth Q\'s

G'day Inselaffe,

Just a point, we never use our Danforth for anything other than a picnic anchor, never deploy it if no one is remaining on board, these a long way from being the best anchor and suited for sand or some mud types but not all.

Keep an eye open for a small CQR or Plough anchor, you will sleep better.

Andavagoodweekend......
 
Re: Danforth Q\'s

Thanks for the varied replies /forums/images/graemlins/smile.gif

I think I'll keep trying with this one for now, to get more experience and make sure I am doing everything right, and meanwhile talk to those who have anchored around here for years to ask what they use.

I have the impression that (almost without exception) all the larger boats in our club have CQRs, and almost all the smaller ones Danforth types.
 
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