To swivel or not to swivel

[GMac]

I completely agree with you there Alain, on most anyway A big problem most have is telling the differance between good and bad. I just don't really know how it is easily over come. You can't trust something just because it has a known brand name on it, that's become very obvious.

We often get offered a new product or see one we think is OK but when we put it to the test it doesn't come up to grade. Thats one reason we always have a damn good play before we actually sell new things, something I wish more would do.

That 2nd swivel certianly looks to have spent a long time underwater. Failure was related to the build quality as you can see by no damage to the other side. It just snapped. That's the very reason we don't use one like that and in our newly release catalouge we even have photos of them and how easily they go bad, next to our good ones

Anywho... back to Salty Dogs mooring.

I see what you mean there Wheels but have to agree with Alain in this case. In a real good blow the anchor closest to the boat does all the work until it lets go and them your onto the back anchor. We are talking some good wave action here so that is what will be the killer. Sure the 1st one will still help (think sentinal) but if the 2nd moves it's quickly into the left over mess of the 1st anchor so starts to move faster and then goes real bad.

I still would prefer the 3 pointer. It just speads the loads further.

I do agree with your comment about rope only up to the boat. I should have mentioned I'd do chain and lots of it but if I had left over rope I'd use that as well. Situations like what Salty is describing are extreme so all we can do is use whatever we can and hope like hell. To make something that is bullet proof would cost big bucks and be doing nothing 99.9% of the time.

[Kuapa'a]

Originally Posted by Paul Elliott

I don't live in hurricane territory, but I have read that the surge and low-pressure effects can raise the sea level quite a few feet.

Aloha,

... my 2 cents. Sea level will rise 1 foot for each 34 millibars decrease in barometric pressure. This is independent of wind generated tidal surge which in and of itself can be massive.

The geophysical characteristics of the anchorage/marina also greatly affect the severity of tidal surge, (e.g., Lake Pontchartrain in New Orleans averages 12'-14' deep. Tidal surge during hurricane Katrina was estimated at 30'.)

Hope this is of some help in planning for significant increase in water depth and consequent rode ratio.

All the best to everyone during what promises to be a wicked hurricane season.

John

[Alan Wheeler]

I guess it is important to which type of anchor is used to tandem set. I am using a design "similar" to Rocna. I also used a 3m(10ft) chain between the pair. I am not sure what Craig of Rocna would recommend for their genuine article, but this seems to work well. Of course, I can only test by placing the boat in full reverse with all of my 130Hp which isn't huge and not have it drag, but I tell ya, they sure bite hard and don't budge.

[Lynx]

Swivels and shackles - Does anybody know when you should you replace them?

I recall reading that chain plates should take 10,000 full loads before failure. I do not recall reading anywhere when a chackle or swivel should be replaced. Compaired to everything else, these are cheep and easy to replace.

The only way that a boat can "Fly" is to get air under it. Adding enough weight to lower it that far could be done. IF you do put water in the boat to lower the draft you will increase the weight and will need bigger anchors (if enough weight is added). The chance of getting cat 5 winds is very small and the problems may be the other stuff being blown towards your boat - trees, boats, homes etc.... Sinking the boat may not be of much help.

There is just not that much out there that can survive the cat 5 winds. Of course, do not stay on the boat and find good underground shelter.

[andrejsv]

My boat is moored in Richardson bay where it has not moved (while I attempt repairs), and I was told it had been there three years. The prior owner told me to 'check the swivel' once in a while, but I had no idea what he was talking about until this weeked, on low tide when I actually saw it off the chain on the boat.

1) How do I do maintenance? Do I use a grease gun and put marine grease on it?

2) How do I find out if it is ok? keep in mind I have no idea how old the swivel is, other that more than 3 yrs old. The whole chain and swivel look complely rusted at least on the surface.. (they look prety hefty though).

My boat is a 51ft ferro, I dont know its tonnage.

I dont plan on moving the boat until I get the engine working again.. but I dont want to come back one weekend and find out my boat gone, and that it hit a multimillion $ south african yatch because the swivel broke.

Thanks for any response.

[Sandero]

I have a swivel and it doesn't always swivel. Anchor comes up with a hochle of chain around the swivel. Why?

[theonecalledtom]

My main concern with the three achor->swivel approach would be the single failure point from the swivel onwards.

What steps would you take to minimise this problem? Perhaps running more than one line from the swivel to the boat?

[fcsob]

Hurricane Anchor System | Colligo Marine

[GMac]

Woow hi-tensile shackles in a permanent mooring. If I lifted that it would be a instant fail. You want to see some of the hi-tensile stuff fizz like a coin in coke. Hope they are using them in fresh water only. Not to mention the excessive number of connections. More connections = more failure points.

Andtejsv - generally (talking steel mooring swivels) if any part of it measures more than 20% less than what size it started at, replace it. But saying that it is possible for some in some places to take 5 years to get to that stage so you can make a judgement call and say 20% in 5 years so give it another 3 and then replace. If the 20% has happened in 2 years replace.

Take a good close look at the bit in the middle and make sure there is not to much wear there. Again if it looks yucky it probably is so replace it.

You can't really put a time limit on mooring gear. It's more a case of knowing the wear rate and then making sure anything is fixed inside the time frame that it takes to get the gear to the scrapping point. It would be handy if you could find out how old the gear is, that will give you an idea as to whether it's wearing at 1 or 10mm per year hence a base to say how long what is left will last.

Don't worry about grease, it'll last bugger all anyway and could possibly make it wear faster. Grease + sand = grinding paste.

Take a big hammer and beat the crap out of everything. It's surprising how well seagrowth can hold bits of rust on making something look a lot better then it actually is.

The same applies to the chains as the swivel or any other attached gear.