Joining Pat Kearns and Jon Klopman this week, our guest panelist is Susan Canfield, who teaches “Inspecting Fiberglass Boats” at The WoodenBoat School (Brooklin, Maine) each summer.
Listen now to find out where surveyors can go to learn what they need to know about fiberglass, including specific books, magazines, websites, formal training courses, boat builders, boatyards, and more.
We start out with questions from custom-builder Derek Kelsall (New Zealand). From the point of view of a builder, why do surveyors look at a design and give it a poor report?
First concern from Kelsall had to do with having PVC foam core below the waterline: Difficult to comment without more context, but in general, core materials are now very much known materials. In general, not many surveyors are asking questions about core materials. Core done right is pretty much accepted. Although many surveyors agree that they are more comfortable with foam core below the waterline than balsa core (meaning no problem with rot.)
Another question was how detectible early ingress of water is in balsa core. Klopman says “very detectable,” but the problem can be in the build, but also there can be a problem when surveyors don’t want to listen, they just want to know which meter to buy.
Kearns says the meter is really just one tool, and it tells her that more testing needs to be done. Canfield notes that leads to another of Kelsall’s questions, namely when is it appropriate to do core samples.
Canfield adds that a good source of information on moisture meters are the articles in Professional BoatBuilder that Jon Klopman has written. Canfield always carries two meters.
Klopman says use a meter for initial detection, and then use a resistance meter before taking small holes from inside the boat. Technically destructive, but often acceptable by the owners. It gets you to the point where you can proceed.
Kearns mentions that she has seen balsa-cored boats now with 30 to 40 years of service and minimal failures. Again, says Klopman, it all comes down to workmanship.
Turning to Canfield’s course at WoodenBoat School (Brooklin, Maine), she tells us that the types of students attending may be USCG inspectors who have worked more with metal hulls; other students are practicing, but new surveyors in the yacht and small craft market; as well as boat owners. The vessel inspectors, of course, are more interested in understanding the whole construction process, much like medical students studying anatomy. Students are interested also in finding out what consititutes good fiberglass repair, and how to offer proposed fixes.
One of the problems Klopman runs into as a teacher is “familiarity breeds contempt” and students often feel they already know about it because they’ve been around it for so long. Still, most people in surveying classes do not have the engineering background and basic structural information. They don’t know how and why the fiberglass has failed.
Canfield agrees that there is a danger when people assume they know enough.
Where are the best resources for structural resources?
Basic failure info is Engineering 101, and engineering is based on failure. People needs to know what failure really means. This stuff is all written down. Sometimes you have to seek sources outside of the marine industry. Talk to the manufacturers. Talk to the folks at Gougeon Brothers, for example. Stay away from the newsstand stuff that is really not technical. Go back and look at Bruce Pfund’s articles in the early issues of Professional BoatBuilder.
As Canfield prepares her course materials, she includes Eric Green’s Marine Composites and Gurit’s guides to composites, as well as articles in ProBoat. It’s a good idea to collect these articles and keep them as your own text book. If we go ahead to create an online courses, this is the sort of material that we’ll want to share.
Kearns has been looking at the first generation of production boats, but she says the amount of time she spends looking at the fiberglass itself (compared to other systems) has astronomically changed. Hull failures and deck failures are not really the big stuff these days; it’s the stuff inside that is so perishable.
First gen boats, says Klopman, were so overbuilt that we don’t see many changes in them. Newer boats and newer construction methods make it tougher and tougher to survey the boats. For example, as we see more carbon spars, do we know how to figure out what is going on with them? That’s amping it up into next generation non-destructive testing equipment. (Note: There will be session at IBEX 2011 on surveying carbon fiber spars.)
Even in production boats, with vacuum-bagging and infusion so prevalent, we have another breed of cat, says Kearns. For example, here’s a five-year old boat that looks okay, but I want to know where it’s been and what its history is.
Another area of struggle? Working with the average fiberglass guy in the boatyard. If the surveyor finds an area on the boat that has become deformed, what happens when the repairer does not support further investigation to find out what is wrong. There’s still a tendency even among professionals to want to move ahead with repair without fully understanding the extent of the damage and what underlying issues may be hidden.
In damage work, surveyors and adjustors are finding that repairers do not want to listen to surveyor opinions. But if someone has experience only with single skin matt and woven roven, that person may not know anything about matching reinforcements.
It’s a difficult situation, and it’s hard to get them to listen until they see their own repair fail. Canfield adds that insurance companies may also want to settle the case, although they do have a responsibility to investigate the claim thoroughly.
Case study: An old Trojan ran agound, and throughout the repair, no one when inside to back patch any of the repairs. Survey report stated that the patch was inadequate, but the person who was most upset was the boat owner!
In closing, our panel recommends seeking primary sources, and to get to know good people who are making state-of-the-art repairs and who can help support your opinion. Also, go out and start making stuff in your basement, and start breaking it! (Plus it’s good for working out your aggressions.)
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