Model Boat Mayhem
Mess Deck: General Section => Full Scale Ships => Topic started by: sjoormen on November 23, 2012, 07:42:21 pm
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I've been searching photos of anchor of soviet Osa and sershen class boats and I found only few and until last one -which is apparently part of brochure of company which made them- and I find it bit odd. Why is it shaped as it is? I would appreciate any detail available - or photos.
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Just my guess: Maybe the small "ears" or projections on each side are meant to make sure the main flukes lay flat on the bottom of the sea, before they dig in. They look similar in function to the long rod across the top of a Danforth anchor.
http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?productId=102090&catalogId=10001&langId=-1&storeId=11151&storeNum=50304&subdeptNum=50319&classNum=50320#.ULAMgaVQPf4
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Aux, you may well be correct. That was my first thought as well. But then I just sort of wondered if the 2 projecting arms wher to prevent the anchor being heaved up too fare into a hawse pipe recess. Easy to imagine those lethal looking flukes punching through a frigates hull! BY.
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What about those triangles at the end of protrusions, they seem sharp too. How heavy are they supposed to be for 40m long boat with displacement around 200 tons?
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Those anchors seems to be on lines not chains is that possible? Well at least winch gives me that idea, I found only this photo and this table for some reverence, but it probably is way off as it is quite different shape
(http://i446.photobucket.com/albums/qq182/sjoormen/653_zpsa3841bfb.jpg)
(http://i446.photobucket.com/albums/qq182/sjoormen/dfwsfg_zps971ef9a1.jpg)
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If you look carefully at the deck you can see the black painted anchor chain. I dont think you would use
a line on a 200 ton ship - I used to have 10metres of chain on my anchor on a 6 ton yacht -
dont forget it is usually the weight of the chain laying across the seabed that keeps the ship from
dragging its anchor - not the anchor itself.
Geoff
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There are lots of variations on the Danforth type design. The various types of protrusion are indeed intended to ensure that the anchor comes to rest in a position that enables the flukes to dig in. The effectiveness of the variations does rather depend on the nature of the seabed as does the type of anchor itself.
As Geoff says, there would certainly be at least a length of chain attached directly to the anchor as this provides most of the holding power and helps keep the pull on the anchor horizontal to the seabed for maximum efficiency.
Colin
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Thanks for answers, it does seem logical that only chains should be strong enough , what troubled me is how is possible to handle chain with this kind of winch. Also from few photos could be seen that chain goes from chain locker trough roller and not around winch, so how (if that is so) do they handle chain with winch, do they pull it around winch manually , it is heavy afterall. Then again how do they handle ropes with chain still around winch. Huh I am sometimes too curious to my own good %%
(http://i446.photobucket.com/albums/qq182/sjoormen/yscaC_zps2ea62e88.jpg)
(http://i446.photobucket.com/albums/qq182/sjoormen/xdsdds_zps8dd75191.jpg)
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what troubled me is how is possible to handle chain with this kind of winch
Well, clearly you can't! The diagram you have put up shows a purely line based manual system running around the capstan down the deck hawsepipe. This does seem a bit odd as, on the face of it, from the illustrations you have put up:
- The anchor is pretty small for the size of boat
- The fairlead at the deck edge where it goes over the side looks rather insubstantial. Usually anchor rodes go overboard at a strongpoint on a vessel either from a hull mounted hawsepipe under the bow or through a reinforced fitting on the bow as it is this which takes much of the strain on the hull.
- When bringing the anchor in presumably they would take two or three turns around the capstan to prevent slippage than then feed the line manually down the deck hawsepipe as it would not self stow under its own weight as chain would.
In fact the whole arrangement looks to be pretty lightweight and unsuitable for anchoring in any adverse conditions. It's more the sort of thing you might sling over the side on a sunny afternoon in a secluded bay while having a spot of lunch!
It would be interesting to have some comments from our professional sailors.
Colin