Rubber Tires as Marine Fenders

[beanbag]

Where can I find rated energy absorption values, reaction values and deflection values for a simple rubber tire used a marine fender.

I have seen several docks for large cargo barges where large diameter rubber tires (in vertical orientation) are hung via cables along the face of a breasting dolphin or wharf seawall. They evidently have been successful in preventing damage to the barge and dock, but I haven’t seen any vendor data to support this.

I wish to perform some calculations to rationalize the history of success with such fenders. Any suggestions where I can find such data? Any rubber tire vendor or engineering textbook out there that addresses this? Thanks.

 

[MikeHalloran]

Large rubber tires, e.g. for earthmovers, are hideously expensive, and are anything but simple.
They are typically used until there is carcass damage.
Only then do they become available for use as dunnage.
The manufacturers probably have models for new tires, but they may not provide the data you need. ... and manufacturers have no incentive to model or measure a fatally damaged tire.

If you really need the data, I suggest you get a nice big hydraulic press, instrument it, and go measure some representative tires.


Mike Halloran
Pembroke Pines, FL, USA

 

[hydromarine]

ISO 17357 MAY PROVIDE SOME GOOD BEDTIME READING

 

[MarineFender]

It is unlikely that you will find proper performance data for tires used as fenders, simply because they are not designed to be fenders. The tires used either on floating fenders (eg Yokohama or foam-filled) are used truck or aircraft tires. The tires typically used on berths can be any used tyre available. In Norway they normally use truck or tractor tires. Unless actual performance tests are performed on tires, there is no reliable data available on energy absorption, reaction force, deflection and/or hull pressure. The variety of tires available is simply too large to generalise performance or to estimate average values. Furthermore, tires are often used in layers (2 or more rows of tires stacked), rather than as single pieces. Which means the interaction between 2 or more stacked tires need to be taken into account as well.

Tires are not fenders. Not intended to be used as them and not particularly suitable for the task. The main reason they are used, is that they are cheap compared to any decent foam, fixed rubber and/or pneumatic fender. The only reasons to use them on pneumatic or foamfilled fenders, is to protect the fender skin (mainly applicable for pneumatic fenders) and/or to increase stand-off at low cost (primarily applicable to foam fenders).

I guess Mike has a point: if you want reliable data, you will need to put tires to the test. Large tires can only be tested at a few facilities. LeHigh University has a large test bench. Fender manufacturers like Marine Fender International (possibly) and Maritime International (certain) may have test facilities as well. Be prepared to pay a substantial amount of money though: a test procedure as specified in the PIANC 2002 report can easily set you back 10 - 15 K USD. In my book, that is money wasted, since tires are not selected for their performance, but merely since they are cheaper than the alternatives, readily available (from stock), do not require proper engineering and are typically installed based on rules of thumb/experience. As long as no captain complains about damage to the vessel,it probably is ok.

I assume that in general performance figures will turn out to be horrible. Relatively low energy absorption (there is not much material available for deflection compared to a proper fender) and high reaction force as the tyre is deflected on its most sturdy part: the heavily reinforced treat region. Which is not very forgiving to a delicate ship's hull. Using several layers of tires, rather than a single one, will improve the performance figures though. But compared to a proper designed fender system, it will be mediocre. Coefficient of friction probably will be high as well. Same as hull pressure, as the contact area is (relatively) small and not evenly distributed.

@Hydromarine: though ISO17357 is indeed good bedtime reading, it will not answer the question, since it applies to pneumatic fenders, not to tires used as fenders. PIANC 1984 and 2002 are probably more usefull. Even though they also do not recognise tires as fenders (or even substitutes).

The only really proper fenders made from tires are the ones manufactured by Schuyler.

http://www.azobuild.com/news.asp?newsID=6857

 

[L4189]

Years ago Boston Towboat swore by DC 9 tires they got for free from Logan Airport. McAllister used fabricated fenders made from cut up tires thread on to a cable. In the last 20 years though new harbor tugs have been built with D shaped fenders made for the purpose attached along the whole length of the hull. Bow fenders are also now made for the purpose. I think that the maintenance is also a lot less and they probably don't leave black marks on your customers hull.