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  1. M

    How much rode do I need at anchor?

    Quite a while ago I wrote something here about anchoring safely. When does a chain work (in deep water) and when does it not (in shallow water), and that for this reason you always have to use a very elastic snubber / anchor rope when anchoring in shallow water, which can also stretch by 1-2...
  2. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    For a Zen Master you are rather unbalanced, my dear chap.
  3. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    Indeed! Thinwater actually did test the f = nu p / v formula using a load cell and confirmed the formula quite well with the efficiency factor nu being 35% for an outboarder and 50% for an inborder engine. My hole point was that everybody can easily measure this on board - or at least get a good...
  4. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    Yep, I think this has become abundantly clear! And after all, an anchor or a load cell would only hinder you when doing AC racing. But you do realise that doing AC racing is not qualifying you per se to say anything meaningful about safe anchoring, do you? Or do you keep losing because you throw...
  5. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    Indeed, you are completely right, it is not the same thing. The difference is that in the stationary case (bollard pull) the propeller is pushing water at rest behind it, whilst when moving the vessel through water, it is pushing water behind it that has already a relative speed with respect to...
  6. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    ok, fair enough, a mid-sized vessel it is then. Personally, I would replace the CQRs with more modern anchors that have way more holding power. The chain is a beast, yes, but in the end, it still holds that the anchor is holding the vessel in place, not the chain. Chain is for damping and for...
  7. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    What is wrong is wrong, I cannot help it buddy. And yes, I know you will not understand it, but that still does not make it correct. 
  8. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    Spelling, my dear friend!  :P
  9. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    Big boats have a different anchor gear than leisure vessels, that is clear. They are not designed to withstand gale forces of wind and consequently the commercial vessel will have to lift the anchor and wait on the high sea until the gale storm is over. In contrast, a smaller vessel like ours...
  10. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    Yes, having and using an anchor watch is definitely a must when anchoring in a tight / dangerous spot. It did safe us the other day when swinging radius was extremely limited and we knew we could not pay out the amount of chain needed. And sure enough, instead of the forecasted 25 kn of wind, it...
  11. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    If the ansatz is reasonable to work out the load on the anchor caused by the engine as f = n p / v, then I can apply the same principle to work out the load caused by a head-on tidal stream. Only head-on, not from the side! I do the same procedure as before, but now with engine with full...
  12. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    Hmm, is SA only there to ask a question? I would have thought it is also of value to share some observations that might help others. I have seen too many disasters at anchorages all over the world and so I know more knowledge on this topic does not hurt. And yes, there is nothing wrong in having...
  13. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    Yes, indeed! Glad we cleared that one up! Slope is an interesting topic when it comes to anchoring. Initially, I thought it must always be better when the slope is such that the water is deeper at the anchor side, so that the pulling angle at the anchor shaft can remain more easily in line with...
  14. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    Yes, sure, agreed. But this does not change the fact that a kellet is not making a huge difference. It still only corresponds to a few metres more chain, not more than that. But at the price of some panic when it has to be retrieved in a hurry. And if you are using a long stretch of nylon, then...
  15. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    Setting an anchor by engine is a very prudent practice, even when tide and wind will change later on. At least modern anchors will reset to accommodate new tide and wind directions without getting unrooted. Rather, the anchor rotates in situ and stays buried. So, this is a very different...
  16. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    Not quite right. Have a look at this description: https://www.cs.mcgill.ca/~rwest/wikispeedia/wpcd/wp/w/Work_%28thermodynamics%29.htm ("In thermodynamics, thermodynamic work is the quantity of energy transferred from one system to another. It is a generalization of the concept of mechanical...
  17. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    Fair enough, thanks for this explanation.  There is never a guarantee for anything when it comes to anchoring, that is very clear. To me, all one can do is to reduce the odds of something bad to happen. In this spirit, when I can establish a rough idea of the holding power I had subjected the...
  18. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    Well, let me tell you - as a theoretical physicist - the law of power = force x velocity is basic mechanics and not thermodynamics. Never has been. And yes, it is a simplification, but confirmed by some measurements and it seems there is reasonably good agreement. So why make it more...
  19. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    Theoretical physicist by training many years ago, indeed... ;)
  20. M

    Reversing the engine when digging in the anchor – how much anchor load does this correspond to?

    Oh well, if you insult a gang member in Brooklyn and in return have his knife in your face - would you call him overly sensitive? I do not think you would. It is just that I have never backed off in my life. So, somebody is giving me shit, I return it straight away. As simple as that. My post...


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