Folks I'm reading a lot about rigging and how good it is and about chain plates that are hard to inspect (and other such things.

In the world that I work in, we take measurements of the resistance of joints - and the trend can tell you what's happening and I wondered how this would translate to Yachts. IE if I took a low impedance measurement from the chain plate to the rigging proper just beyond the joint and trended that, could this tell us something about the state and trend of the state of that set of connections (That I am assuming is a main fail point). We measure joints to the micro ohm, and corrosion shows up as an increase, rigging is just metal wire connections - and the load on the joints we monitor (HV Connections in power lines and equipment) can be several tons. The equipment to do this is man portable, and not dangerous to use - could be done at a mariner or on haul out. Has anyone had experience of this type of testing and could there be an appetite for this testing.

Likewise we use digital X Ray to do all sorts of studies - and given there are a lot of "nonmetal" boats out there with critical metal parts (chain plates hidden in hulls??) could a digital Xray of critical parts be a tool a in a survey???

By way of disclaimer - I don't provide these type of service - I use them in my work.

Curious to see what others think or have experience of??



Ian

I don't know but I do underwater cleaning and video inspections of hulls. . No disclaimer.

For sure there is a market but up the big end of town probably, eg;

www.int-ndt.com/what-we-do/marine/

NDT is part of condition monitoring in operations and maintenance which ranges from "drive it till it breaks down then get out and buy a new one" - ie the stack of crushed cars at wreckers, to preventive maintenance which is regular log book servicing, to predictive maintenance which includes NDT as well as many other techniques. And there are a myriad of other methods and techniques in between all these as a basic google search will turn up..............over the last 20 years not many new techniques have turned up but the bs regarding predictive maintenance across all industries has tripled...........

So the normal rule of thumbs still hold for dinghies, skiffs and yachts up to (say) 30ft - 10 years for standing rigging life, inspect chain plates and fasteners yearly, if rust weeps are evident renew the fasteners and fix the water ingress causing the rust, ensure aluminium masts don't have galvanic corrosion thickness wastage under stainless fittings due to barrier coatings (eg Duralac) breaking down. Many masts have broken at spreaders under ss spreader bands - I just got mine in time on a Farr727. Tefgel is a lot better than Duralac imho.

When a certain maxi yacht had a rig issue the standing rigging was sent to the oem in Spain for ndt examinations...........not a $2 job..........

www.wildoatsxi.com.au/news/wild-oats-xi-clearing-hurdles-for-hobart/

Google "Integrity testing of embedded fasteners" by C. Charlesworth and J Everton. Water Journal May 2015. These guys are using ultrasound to check out embedded bolts. I have been meaning to talk to them about applying to keel bolts and buried chainplates.
Let us know if it can be done.