Old fashioned mooring system with floating pole ...

[kengrome]

Sorry for posting this here but I could not find a "boat related" forum and this one seems to be the closest to what I need, so hopefully someone here has seen what I'm looking for and can help me ...

I saw an interesting mooring system on a web page a year or so ago and I cannot find it again. From what I recall it was made of a wooden pole that was maybe 4-6 (or 8 inches?) inches in diameter and it was attached by a chain or rope to some kind of anchor, or chunk of concrete, or engine block, or something else that didn't move on the bottom.

The pole floated vertically and maybe 1/2 or 1/3 or 1/4 of it was out of the water and the rest submerged. It had some kind of steel ring on it, and I think this is what the boat attached to.

From what I can remember, the ring on the pole was supposed to slide up and down, and the whole system was supposed to act like a shock absorber to dampen the effects of waves and currents. I recall that the article said it was an old-fashioned system that few people use any more but that it was very inexpensive and effective.

If this info "rings a bell" with anyone, and if you can point me to the web page or send me a copy of the pix and/or the description of this mooring system I would certainly appreciate it. Thanks in advance.

[Tim B]

Do you mean a pile mooring?

These are long poles driven into the river-bed, with a ring around them to chain a pontoon onto, the boat is then tied to the pontoon. There are usually two poles (one at each end of the pontoon).

Tim B.

[kengrome]

No, this system uses a floating pole that is attached to the bottom with a chain or something similar. I think the pole was pulled deeper under water when waves or currents tried to move it, then the pole would float higher again as they passed.

But there was more to it than that.

I'm just guessing when I try to describe how it works because when I first saw the web page with a picture and text I didn't take the time to look at it carefully and memorize how it works -- and now I wish I had.

[charmc]

Originally Posted by kengrome

From what I recall it was made of a wooden pole that was maybe 4-6 (or 8 inches?) inches in diameter and it was attached by a chain or rope to some kind of anchor, or chunk of concrete, or engine block, or something else that didn't move on the bottom.

The pole floated vertically and maybe 1/2 or 1/3 or 1/4 of it was out of the water and the rest submerged. It had some kind of steel ring on it, and I think this is what the boat attached to.

I recall that the article said it was an old-fashioned system that few people use any more but that it was very inexpensive and effective.

Ken,

Welcome to the forum. Spar buoys have some advantages over other types:

"Use of a spar buoy. A spar buoy design is well suited to waters with short-length, choppy waves. Use of a sparbuoy design, with constant tension on the moving chain will avoid slamming and jerking of the surface buoy.

Such a buoy can withstand fairly rough weather although may be not a full-blown hurricane passing directly overhead. With a spar buoy design all the loads can be transmitted via the nose cone to the centre-pole (a three-chain bridle can be avoided). The buoy can move up and down in the water and adjust to changing loads more gradually than a flat cylinder buoy. When properly ballasted with chain as external load, the buoys have a very seaworthy motion. Even in choppy waters, the spar buoy type float will dampen motions and will not jerk or slam like a flat tyre-type buoy.

Divers on a spar buoy type FAD used in Curacao confirmed this through observations. The spar buoy was able to withstand periods with very rough seas; we believe that the fact that this type of design was used is a decisive factor in determining the survival of these buoys in the open seas." http://www.fao.org/DOCREP/005/Y4260E/y4260e06.htm

"Our preliminary analysis indicates that the spar buoy roll/pitch
motions much lower than typical oceanographic buoys. For example, Harris Corporation reports that the
pitch rate on their buoy in Sea State 6 (Hs = 5.5m) is 25 deg/sec. This compares to less than 9 deg/sec for
the spar in a comparable environment." http://obslab.whoi.edu/SparBuoy.pdf

A spar buoy dampens lateral force, as in wind effects on a moored boat, at least partly because 50% or more of its length is submerged. Added to the dampening effect of the mooring chain from the buoy to the bottom, and it is very effective. One reason they may not be used any more for moorings is that in the US spar buoys are used for marking special areas, often to mark areas in which you may not moor.

[charmc]

Sorry, Ken, I'm trying to multitask and didn't notice either your location or the fact that you've been on here longer than I have!

A company in New Zealand makes spar buoys; I don't know if they are adapted for mooring duty, but you can contact them and ask:
http://www.seadevilproducts.com/

[kengrome]

Thanks everyone for your help in my quest to find more info about the mooring system I described. Note that this is not the only forum where I posted a request for info about this type of mooring system.

A member of the other forum found the exact article I was looking for. He scanned it for me and posted it in that forum, and I linked to the scanned images here for anyone who might be interested:

[Guillermo]

The same idea, but more technological:
http://www.hazelettmarine.com/