charlieannear Posted March 13, 2006 Report Share Posted March 13, 2006 How do you calculate the size of buoy you need? Quote Link to comment Share on other sites More sharing options...
Newboy Posted March 13, 2006 Report Share Posted March 13, 2006 Any chandler wil have a chart for this. Just tell them what size anchor and how much chain. The buoy cost between Quote Link to comment Share on other sites More sharing options...
Afishionado Posted March 13, 2006 Report Share Posted March 13, 2006 How do you calculate the size of buoy you need? A short answer is nowhere as big as you imagin, the lifting power of even a football sized bouy is immense. One the size of the school gyms medicin balls is about right. Too large and they get in the way and are impossible to stow. The boat jumble season is about to start, and one can buy at a lot less than chandlers prices. If you enter 'Boat Jumbles' into Google it will give you sites showing where and when boat jumbles are all over the country. If you go to any of the local ones every second person will be a member of this club Mad Mike Quote Link to comment Share on other sites More sharing options...
TomBettle Posted March 13, 2006 Report Share Posted March 13, 2006 I do have a ridiculously large one on my other boat "Nautibusiness". It is WAY over size at around the size of a large childrens "space hopper". When driving the anchor out it still submerges, but has never failed to pop the anchor to the top. However the size wasn't the issue for me as I knew much smaller would suffice, the big ball shaped fender makes a perfect forward fender for those bad boat driving days that we all have and has prevented many an otherwise embarrassing moment when coming alongside just a tad too hard or an incy whincy bit out of shape. Something of about 14 inches across would probably be absolutely adequate. Tom Quote Link to comment Share on other sites More sharing options...
Newboy Posted March 13, 2006 Report Share Posted March 13, 2006 I know the one, it's the same as mine. I chose a large one so that I can wedge it into the bow rail. The only downside is children lauge at my boat when towing, it looks like a giant red nose. Quote Link to comment Share on other sites More sharing options...
Paul D Posted March 13, 2006 Report Share Posted March 13, 2006 Charlie, I got mine made up in Christchurch Boat Shop - It is one of those mooring buoys which you can pump air into ( about the size of a large football ). You are welcome to borrow mine to remind the guy in the shop what is needed and get another made ( he did a superb job ). Quote Link to comment Share on other sites More sharing options...
Afishionado Posted March 13, 2006 Report Share Posted March 13, 2006 Using the Alderny anchor and retrieve method that most of us use, one needs to be conscious of how much deck space a large bouy would take up. The whole idea of the Alderny method is to stop the need for tricky manouvers on small foredecks and the need for anyone to leave the safety of the cockpit. Mad Mike Quote Link to comment Share on other sites More sharing options...
charlieannear Posted March 14, 2006 Author Report Share Posted March 14, 2006 Using the Alderny anchor and retrieve method that most of us use, one needs to be conscious of how much deck space a large bouy would take up. The whole idea of the Alderny method is to stop the need for tricky manouvers on small foredecks and the need for anyone to leave the safety of the cockpit. Mad Mike Exactly Mike, which why I'm trying to find out what's the smallest I can get away with, as on the Shetland I haven't got hatch/windscreen access to the foredeck. Does anyone know of an online source for a chart similar to those which say what size anchor you need for the length of boat? i.e Specifying bouyancy of buoys by size. Then you can say for 5kg anchor and 9m of chain, you need an X" buoy to float the weight. Quote Link to comment Share on other sites More sharing options...
duncan Posted March 14, 2006 Report Share Posted March 14, 2006 what you are really lloking for is the size of buoy thet will keep you anchor and chain on the surface once it has lifted them clear so........ work on 1kg/m for 6 mm (generous but safe) chain or 1.5 kg/m for 8mm chain then add your anchor weight and you have the weight you need to support. For 9m / 6mm and a 5kg anchor this would be 14kg. now you know you need a buoy of at least 14l volume ('cos 1l displace 1l water = 1kg water) and preferably more like 18/20l. finally a 20l buoy will either have "20l best cooking oil/soy sauce/whatever" convienently stamped on it or, if spherical, have a diameter of ........cube root, .......pie..........number I first thought of............ 172cms (maybe) (probably best to get a child to do the maths just in case............ Quote Link to comment Share on other sites More sharing options...
charlieannear Posted March 14, 2006 Author Report Share Posted March 14, 2006 Thanks Duncan! Quote Link to comment Share on other sites More sharing options...
plaicemat Posted March 14, 2006 Report Share Posted March 14, 2006 As an addendum to this topic, I offer the alternative to the 'coat hanger' method of keeping the bouy away from the bow of the boat. It was one of the few things I got from the Go Fishing Show, courtesy of the AnkaYanka chaps. When you have nearly let all of your warp out, attach another much smaller bouy behind (boat side) the main bouy and attach the same way as the 'coat hanger', i.e., take a bight through the ring and over the bouy which will fix it in position but make it easily removable. Now let out a bit more warp, taking this bouy about 20mtrs, or whatever you prefer, away from the boat. Recovery sees the small bouy coming aboard first followed eventually by the larger bouy and anchor. The small one can either be removed upon retrieval or left in place if you are going to be in a similar depth of water. I hope I have made this clear enough to understand. Obviously, the AnkaYanka chaps were selling this extra at a show price of Quote Link to comment Share on other sites More sharing options...
toerag Posted March 14, 2006 Report Share Posted March 14, 2006 Have a look on here, this site gives the buoyancy in lbs for each buoy. http://www.saeplast.com/servlet/Saeplast/g...ductgroup=BUOYS Weigh your anchor and chain, then work out what buoy you need. I nearly collected a washed up A6 bobber last weekend, but someone else got to it first! Quote Link to comment Share on other sites More sharing options...
Afishionado Posted March 14, 2006 Report Share Posted March 14, 2006 Quote........ Weigh your anchor and chain, then work out what buoy you need........ I'm afraid not too acurate advice. Things weigh a lot less in water than they do on dry land. Therefore 10lb on land would only weigh about 6 lb in water. Also and mainly, it is not just the weight of the anchor and chain that you need to lift, it is the break out pull that needs to be sufficient. Now without going into physics and the other sciences involved let it suffice that the indications of the size you require is one that is a bit bigger than a football and a bit smaller than a space hopper. By the way the colour makes one hell of a difference the red ones lift much more than the orange ones. Mad Mike Quote Link to comment Share on other sites More sharing options...
Newboy Posted March 14, 2006 Report Share Posted March 14, 2006 My guess is that the calculation has already taken into account the effect of weigh in water. So the calculation would be pretty accurate, otherwise many angry boaters would have already brought their buoy back saying it's no good for lifting my X kg anchor. Why would the yellow/orange/red buoy has any different buoyancey? Even if the plastic are different, surely it would be insignificant to alter the bouyancy too much? Another thing is that you can always pump up the buoy for extra buoyancy. Quote Link to comment Share on other sites More sharing options...
Seamouse Posted March 14, 2006 Report Share Posted March 14, 2006 Why would the yellow/orange/red buoy has any different buoyancey? Whoops! You just took a Mad Mike Special Statement seriously, Kam Steve Quote Link to comment Share on other sites More sharing options...
Afishionado Posted March 14, 2006 Report Share Posted March 14, 2006 Mad Mike Special Statement Moi? It's about as acurate as weighing ones anchor and chain to see how big a bouy to buy Mad Mike PS I once rescued a bunch of blokes who were drifting ashore with a dead engine. Their anchor was a 56lb coalmans weight! They could not understand that if the bloody boat was holding them and a 100hp engine up on the surface then a 56lb lump of iron would have no affect at all. It aint the weight it's the grab that matters!! Quote Link to comment Share on other sites More sharing options...
TomBettle Posted March 14, 2006 Report Share Posted March 14, 2006 I do enjoy this forum!!!! Charlie: Get one slightly bigger than the chart on the website that the post before suggests. I do agree with Mike that it is one thing having the bouancy to float the whole lot, but another to break it out. eg: If the chart suggests have a 14" bouy, go for one that is 16". Check out the chart, the bouyancy is almost double for very little extra space. After reading Mike's bit about coloured fenders it is making me wonder how much of his "advice" I have heeded in the past that wasn't really GOOD advice! Oh joy, the PBSBAC forum and Mad Mike have made me smile on an otherwise stressful day! Quote Link to comment Share on other sites More sharing options...
charlieannear Posted March 14, 2006 Author Report Share Posted March 14, 2006 Yep, that's my normal strategy with most things, i.e. find out what I need and then go one bigger! Quote Link to comment Share on other sites More sharing options...
Afishionado Posted March 14, 2006 Report Share Posted March 14, 2006 Yep, that's my normal strategy with most things, i.e. find out what I need and then go one bigger! Same with wimmin? Mad Mike Quote Link to comment Share on other sites More sharing options...
Adam F Posted March 14, 2006 Report Share Posted March 14, 2006 Why would the yellow/orange/red buoy has any different buoyancey? Even if the plastic are different, surely it would be insignificant to alter the bouyancy too much? Another thing is that you can always pump up the buoy for extra buoyancy. CLASSIC!!!! I havent laughed out load for a long while like that!!! ....of course everyone knows that red paint weighs less that yellow and therefore dont lift as well!!! Quote Link to comment Share on other sites More sharing options...
TomBettle Posted March 14, 2006 Report Share Posted March 14, 2006 My favourite is the stripey paint. Mike if you are nipping down the chandlery, do you mind picking up a sky hook for me and whilst you are there can you ask the guy at the counter for a long weight... Quote Link to comment Share on other sites More sharing options...
Fugazi Posted March 14, 2006 Report Share Posted March 14, 2006 Mad Mike is way off the mark regarding colour and I can speak from years of experience when I say that white provides far greater buoyancy for the same displacement volume. The reason being that white reflects neutron particles radiated from the sun better than colours in the white light red spectrum. The ground effect caused by downward vectored neutron particles reacting against the water surface provides additional lifting capacity. Gordon H Quote Link to comment Share on other sites More sharing options...
TomBettle Posted March 14, 2006 Report Share Posted March 14, 2006 Gordon There could be more than an ounce of truth in what you say, however I would suggest that black would be the best colour here. Black absords the heat on a warm day more than any other colour and as such will expand more creating more bouyancy. On the flip side a well pumped up white fender is likely to be better on a cold winters day as it will not deflate so quickly... Quote Link to comment Share on other sites More sharing options...
Afishionado Posted March 14, 2006 Report Share Posted March 14, 2006 Mad Mike is way off the mark regarding colour and I can speak from years of experience when I say that white provides far greater buoyancy for the same displacement volume. The reason being that white reflects neutron particles radiated from the sun better than colours in the white light red spectrum. The ground effect caused by downward vectored neutron particles reacting against the water surface provides additional lifting capacity. Gordon H Worra load of photons! Mad Mike Quote Link to comment Share on other sites More sharing options...
Fugazi Posted March 14, 2006 Report Share Posted March 14, 2006 At last a bite! Much better than 3 hours without one on Southbourne beach last Sunday, has anyone else heard the acronym BSWC (Bull**** Stated With Conviction). Gordon H Quote Link to comment Share on other sites More sharing options...
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