ab1974 1 Posted July 17, 2012 Share Posted July 17, 2012 Just somethng Ive been mulling over in my head. The cat has just been finished in coppercoat (yep I can be the official crew.org tester) antifoul. One of the reasons is the cat can be beached on her keels and scrubbed down. The motors can be serviced in situ, so the need to haul out is minimised. When beached, the cat is bum heavy so wants to sit down on her rudders as the tide falls. Ideally I dont want to do that, I want her to sit level on her keels. The previous owner used to take a halyard from the top of the mast to a tree ashore and crank the halyard to keep her upright. My thought is that is ok if there is something suitable close to shore, but often there may not be or because of the seabed fall you may be too far away. Was thinking a buried tyre or piece of ply would suffice, then someone mentioned a sand screw anchor. Few searches and I discovered the helix moorings. Put one of these into the sand and then tie the halyard to the anchor. So few questions: - would they hold a reasonably vertical (say 45 deg) pull? - anyone use them as a semi permanent anchor? In fact what is the definition of a mooring? Could you dive down put one in for a few weeks holiday and then remove? - does anyone sell them here? - presume id want a larger one if it were to actually be used as an anchor / mooring rather than just to hold her upright when beached. Guess they are not really any different to a hand auger used by geotechs etc except galv and high tensile? Link to post Share on other sites
ab1974 1 Posted July 17, 2012 Author Share Posted July 17, 2012 This is an example http://www.go2marine.com/product/88163F ... nchor.html Link to post Share on other sites
Guest Posted July 17, 2012 Share Posted July 17, 2012 So few questions: - would they hold a reasonably vertical (say 45 deg) pull? Yes. how much depends on what size screw you are using but they can hold large numbers - anyone use them as a semi permanent anchor? In fact what is the definition of a mooring? Could you dive down put one in for a few weeks holiday and then remove? In NZ probably knot but they are used in NZ Aquaculture, a super duper sized anchoring system that lives in the water, you are a healthy lad but I've love to see you try. They take a fair amount to screw in and they are done here by hydraulic rigs. - does anyone sell them here? Yeap a few places, even made here. - presume id want a larger one if it were to actually be used as an anchor / mooring rather than just to hold her upright when beached. Yes Guess they are not really any different to a hand auger used by geotechs etc except galv and high tensile? High tensile probably knot as HT stuff doesn't like living in water that much and can be fragile or brittle I suppose is a better word. They aren't used in permanent boat moorings in NZ generally as they need special gear to install, near impossible to inspect and when they wear out, which they do do, they just become rubbish cluttering the seabed. As a temp thing why knot by I'd suggest you try and get one in then out before committing to hard as you may just be surprised at how tricky that is. I'd be thinking a wide dai one you could wind in with a big bar but as you'll run out of grunt shallowish the wider will grab more ground sideways as you'll most likely be ground depth challenged. Worth sussing a bit more I think AB but don't do it thinking 'Wind that in and out easy peasy' as it's most likely you won't. Surly someone at your work knows someone who has or makes them. They are used a lot on land. Those wire braces holding up power poles usually have those on the ground end. Also used to holding retaining walls and alsorts of stuff like that. Ask around and you maybe able to grab one for a play on the beach before spending your own coin. Link to post Share on other sites
Guest Posted July 17, 2012 Share Posted July 17, 2012 What about a couple of simple props at the other end? Link to post Share on other sites
ab1974 1 Posted July 17, 2012 Author Share Posted July 17, 2012 Orge - had thought of that - but bit worried a passing stinkpot / ferry wake could cause some serious damage if the cat bounces and I would still need a large base / platform so the props dont sink into the mud. Thanks KM. Hopefully I can track one down through one of the boys. Assuming I just want to use it purely to hold the cat upright while doing maintenance, I am guessing I might only need a 200-250mm dia one. How hard would that be to drive into wet sand?? Link to post Share on other sites
Guest Posted July 17, 2012 Share Posted July 17, 2012 How hard would that be to drive into wet sand?? Knot as easy as one would expect. They do have a good sized surface area and that grabs well. All depends on the sand really. Tried winding the head of a good sized post hole borer into the ground? It's the same thing. Maybe a smaller 100mm one and wind it in deeper than a big one shallower?? I'll suss, I have a feeling I may have one in our twilight zone.... the place weird stuff goes into and is rarely seen again. I think there still maybe a customer in there, wondered in mid last year and hasn't been seen since............. shite..... unless Wheels got him Link to post Share on other sites
grant 40 Posted July 17, 2012 Share Posted July 17, 2012 we bought a couple about 200ish mm a few years back, will try and find where we got them from. One has been installed in about 5 metres of water, two army lads on scuba with a large bar swimming in circles, no worries We did try on on exposed sand bar, i.e. we were walking in circles, not too bad to put in, but will depend on what you are screwing into. Definition of a mooring? yep, they would fit the bill there, need to talk to your local "them who administer moorings" to check what the specific rules are. In Wellington if it is in place for less than 31 days annually it is temporary, any more you would need mooring consent. If you are just using it while drying for maintenance you might slip in as a temp user, if you're in Auckland get hold of Bruce at the Harbourmaster's office Link to post Share on other sites
rigger 47 Posted July 17, 2012 Share Posted July 17, 2012 Orge - had thought of that - but bit worried a passing stinkpot / ferry wake could cause some serious damage if the cat bounces and I would still need a large base / platform so the props dont sink into the mud. Instead of hard props what about some large diameter tube fenders - double duty, props when beached and fenders for a raft up???? Link to post Share on other sites
ex TL systems 63 Posted July 17, 2012 Share Posted July 17, 2012 what about making a couple of big bags to hang in the water off the front beam, as the tide drops they would hold the front down. Or just balance it with a bit more weight forward on the day. Or reinforced pads on the back beam with a pin to take pivoting alloy props with a foot. Re the helix mooring I watched a 42ft cat pull one out at Little Shoal Bay one windy day, it was part of a drying mooring in the mud there, buryed car tyres hold in better, and take about 30 minutes to install or remove. Was that your cat that had a slight argument with the cradle at Okahu Bay, I thought it was an escape hatch going in the bridgedeck. We are still pretty happy with the coppercoat on Fair Curve. Link to post Share on other sites
ab1974 1 Posted July 17, 2012 Author Share Posted July 17, 2012 KM - have access to a 100mm auger. Might take to the beach for a play. Rigger - where / how were you picturing the large fenders working? TL - yep was us with the little incident. All sorted now. Coppercoat on. Be good to compare notes. Have thought about shifting weight. Bags filled with water and some sort of trip line not a silly idea. Just not sure how much weight I need forward! Link to post Share on other sites
rigger 47 Posted July 17, 2012 Share Posted July 17, 2012 Rigger - where / how were you picturing the large fenders working? Not sure what the length the rudders are, but by wedging (and securing) fenders under hulls to stop rudders contacting. Would give some spring / shock absorbtion for wake / waves going through? Might be completely useless idea for your boat. Did work to prevent further damage on a keeler we found aground, owner was pleased. Link to post Share on other sites
wheels 543 Posted July 17, 2012 Share Posted July 17, 2012 You would be best to simply row (or lay at high tide or walk at low) your anchor forward and pull it back in on the anchor winch to gain some tension. That will pull your bow down just fine. Keep it simple. You don;t need to make this complex. Link to post Share on other sites
Guest Posted July 17, 2012 Share Posted July 17, 2012 I've been involved with screw anchors quite a lot and would never use them again after discovering the mantaray system. Screw anchors are dangerous and very liable to failure if they cannot be buried right up to the shackle hole. This isn't a problem with mantaray, plus they're a lot quicker to install and can have a proof load put on them. Link to post Share on other sites
ab1974 1 Posted July 18, 2012 Author Share Posted July 18, 2012 Thanks Rigger. Can see in concept, but for me they'd need to be bloody big. Wheels - that was my first option, but while simple I guess there are a few concerns. With the anchor walked or dinghied out say 30m forward, and then cranked on so it sat tight over the forward beam, I was really wondering if that would hold it down. The line will obviously have horizontal tension, but will still have some vertical stretch. Bit like trying a rope between two points tightly, then go pull it in the middle - can still be done. Only needs to allow the boat to move up 600mm at the bow and I'm probably sitting on the rudders! Might be worth trying once I've got it tied off to something onshore from the mast head, which will have more of a downward pull. Pete - Had dismissed using the helix as a mooring. Am really just after a temporary (say 6 hours in a bay) to keep the boat upright. Not sure how much weight I need up in the bow to get it to sit upright. Link to post Share on other sites
Murky 1 Posted July 18, 2012 Share Posted July 18, 2012 There is a guy up this way who I *believe* has carried off what you are describing with what I think is a 45-foot Alan Wright cat using a pair of sturdy sawhorses. Sorry for the vagueness, it was a couple of years ago and I wasn't paying enough attention to give you a really accurate answer. Big fenders filled with water maybe? Might be easier to keep in place. Apologies for the dart-throwing... Link to post Share on other sites
Guest Posted July 18, 2012 Share Posted July 18, 2012 easy fix,plastic 44 gallon drum tied to front beam with bridle so that it'll sit on the bottom when the boats level tie drum on, chuck it off to fill and bobs your uncle, it that dont work.......chuck 2 off Link to post Share on other sites
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