Andy Loops Posted October 20, 2008 Share Posted October 20, 2008 Hey guys wondering if there was a cheap solution to getting a decent length of rope - looking for 200m+ for anchoring in 100m+ water. Cheers Andy Link to comment Share on other sites More sharing options...
GregL Posted October 21, 2008 Share Posted October 21, 2008 Hi Andy How weird, I was just ordering 250m of 12mm rope myself! Thought I would need that much if I ever felt the need to anchor at the 12mile...... Just got my local to order it threw BLA. They can do any length I think as they come off a massive roll. Greg Link to comment Share on other sites More sharing options...
Dreamtime Posted October 21, 2008 Share Posted October 21, 2008 Hi Pete appreciate the offer. Boat is 25' and around 4t though - was thinking 12mm would be the go. Any raiders have a view here?? Cheers Andy Mate, that's a good price, it's advertised on another site for $147.00 retail for 220 mtr roll. My 90 ton, 75 foot vessels only run 22 mm rope and it works adequately, and we've never broken a rope. 10mm has a breaking strain of around 1.5 to 2 tons, more than enough to hold your boat. Hope this helps. Cheers Link to comment Share on other sites More sharing options...
GregL Posted October 21, 2008 Share Posted October 21, 2008 Question.... Is a anchor rope stated strength measured on dead lift weight, ie 2 ton? Is a 5 ton boat ever going to create 5 tons preasure on a anchor rope? I was asking these questions earlier to myself... Greg Link to comment Share on other sites More sharing options...
pelican Posted October 21, 2008 Share Posted October 21, 2008 (edited) Question.... Is a anchor rope stated strength measured on dead lift weight, ie 2 ton? Is a 5 ton boat ever going to create 5 tons preasure on a anchor rope? I was asking these questions earlier to myself... Greg Most cheap polly anchor ropes are not really rated but they imply 2 ton dead lift but are not designed or reccomended for that purpose. Go for a better quality and layed nylon rope for better reliability especially in regards to shock loads and there ratings are more reliable in real life and last longer under stress. 5 ton answer - well yes and no- should never happen really ( I have seen boats motor off forgetting their anchor was down!!) - unless you have anchor snag you would never have enough holding power on the bottom or fittings on deck that would take it for long. The bow in the anchor rope , chain and stretch in the rope protect it from a shock load. You could create a 5 ton force against the rope under power but generally the force on the rope is the tide and windage sum and any momentum should there be any slack in the system. Ifthe situation was to occur that the anchor was wedged , chain was off the bottom and rope was at full tension a large or breaking swell will snap ropes. When towing boats we have had very heavy rope snap, fittings break when the towing boat exceeds the hull speed of the boat it is towing as it is like towing a 20 ton bow wave in front of it. 3-5 knots extra makes a huge difference in strain on the rope and fuel usage but nearly no extra speed in the tow. The big difference in 10-12mm rope is it handleing in your hands and laying it in the anchor well or rope bin. 12mm and up nylon lays better and if required to do a hand lift you can get a grip on it but it does take more stowage space but not having rope burn is worth it for me. Nylon rope of about 12mm has really good abrasion resistance if you are using a buoy retrieval and isn't that expensive and you tend not to lose it if you use a triggered anchor. There are several methods used in survival or storm conditions where using drogues and anchor buddy style arrangements where you can limit the total force and shock loads ever exerted on complete anchor apparatus which increase holding power with less stress on the rope. Pel Edited October 21, 2008 by pelican Link to comment Share on other sites More sharing options...
Robbielites Posted October 21, 2008 Share Posted October 21, 2008 Greg, What Pel said From memory, the general rule of thumb for Nylon rope WWL (Working Weight Limit/Breaking strain) is Diameter squared mm x 8kg. So, 12mm rope x 12 x 8kg = 1152Kg. Would I try and lift (Dead weight) a 1152Kg boat with 12mm anchor rope? Probably not! The key words in Pelicans reply were "Shock Load" Shock load can not be determined in rope or chain, you just try avoid it like buggery and compensate with larger diameter better quality rope Link to comment Share on other sites More sharing options...
GregL Posted October 21, 2008 Share Posted October 21, 2008 Thanks Pel!!! Much better in my head now. At the start I thought 10mm would be the way to go but was advised to go to 12mm by BLA just to be on the safe side. I went a nylon rope as the silver thread stuff only came in 100m spools. I wanted 250 for deep water and no joins so a anchor mate could be used. Next is what is the best type of sand anchor to use. The big plough style like the ones hanging off the front of game boats or the flat style twin blade ones? I was told 4m of 8mm chain will do, is that right on a 8m boat? Greg Link to comment Share on other sites More sharing options...
pelican Posted October 22, 2008 Share Posted October 22, 2008 (edited) Greg there are 2 ways to look at it a fishing anchor and overnight - I want to sleep anchor. We use 2 different setups. a lightweight set up ( cheaper if we lose it) in a tub and if it holds good we are happy as it is easier to retrieve and work with and a heavy set for overnighting which doubles as a "faaarrrrk - lee shore öh shit" why won't the motors start anchor. We carry a spare length of chain and shackles as well to heavy up the lighter rig.. The light setup get used all the time as a stern anchor at beaches as well. The chain and scope of your anchor rope should all the work when anchoring and the physical anchor is just a stick in the sand at the end . It is important that when dropping it has enough mass to beat the chain to the bottom so the lead tipped ones work better. Think about a moloolobar pick or a heavier lead filled reef anchor with short stiff prongs still using zip ties.. It depends on how strong your back is?? as chain gets heavy on a straight lift and you can't always use the anchor mate inshore. So get your decky up the bow with anchor and 6m of 8mm chain and see if they still want to be your decky as it is hard work but 6 or 7 m is far more reasonable than 4 which seems far too short. For fishing I don't think 4m of 8mm chain would be anywhere near enough ever excecept at Balmoral but then the guys are trying to sell you a lightweight anchor and they don't want the chain to hit the bottom before the anchor and tangle. We have our cheaper fishing anchor tripped with zip ties so it is less likely to get stuck and surprise surprise after losing several expensive quality anchors since we have started doing this several years back we haven't had to trip one. Bloody Murphy's law. We have spare shackles so if it is needed as an emergency anchor we just shackle it solid. Our heavy overnight anchor on a 3t plus boat with lots of windage etc is a big lead tipped plough ( biggest that will fit in the well, 7m of 10mm chain and 14mm nylon rope with caribina and emergency buoy in the well. We have a 6m length of 8mm that we can shackel on as well and a extra length of rope. Our fishing anchor is 12mm nylon 7m of 8mm chain with a smaller plough, sand , or heavy reef attachable . You really won't know till you have your boat out there and see what will work on different bottoms and how hard it is to handle be it with a buoy lift or a straight haul ( ouch) I like the stress free drum anchor winches but have been to tight to bother and the decky does a great job anyway so i wouldn't want to deprive that duty from them. Pel PS if you go to one of the quality anchor websites - Manson etc they will have examples for the sailors on chain and anchor combinations from memory and they are valid for powerboats as well. Just re read that post - info is there sorry it is so hard to read but got to do some work Edited October 22, 2008 by pelican Link to comment Share on other sites More sharing options...
GregL Posted October 22, 2008 Share Posted October 22, 2008 Thanks Pel for your time and effort. It does all make sense..... Years ago I remember I was told 3/4 length of the boat should be the chain length. I'm not sure on how much fishing I will do from an anchored boat as it's just not my cup of tea but I want to be ready if need be. Regards Greg Link to comment Share on other sites More sharing options...
sportfish Posted October 22, 2008 Share Posted October 22, 2008 Have either of you guys checked out the SARCA anchor I got sick of anchoring near bribges or other structure only to have to pull upm and move because the anchor kept slipping Got a SARCA and on sand, mud , gravel so far no problems even with wind and chop - doesnt slip. Havent used it on a reef yet SARCA website has heaps of pics plus video footage Link to comment Share on other sites More sharing options...
pelican Posted October 22, 2008 Share Posted October 22, 2008 Seen em and mate uses his and like it but on bigger boats they are pretty expensive and everytime I put a good one on the end of the string the hard bits down there take a liking to it!!!!! The fixed shank also makes them hard to store in a well easily. The way the mud clears off them is a bonus and they do seem to have a sensible angle on the flukes that looks lik it will work. Might be able to get away with a slightly smaller one than normal as they have good holding power. Pel Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now