A SEARCH FOR METERS

I really enjoyed Mr. Sherman’s article on saildrives (“Driven to Vigilance,” June 2017). In it, he recommends “installing a hull-potential meter on any boat equipped with saildrives.” I’ve searched Google for such hull-potential meters and have come up blank. Could Mr. Sherman point me to where I can obtain one and perhaps mention an OEM? I have a Yanmar SD and motor in my 2015 Beneteau Oceanis 38 and am constantly battling corrosion in the San Francisco Bay marina where she is kept. John Henry, via email Ed Sherman replies: Promariner sells units — one portable and another that can be panel-mounted — for conducting periodic tests. The beauty of these is that you will be able to check rather precisely when you need to replace anodes. These can be found at promariner.com; go to their 2017 catalog, page 39.