Mailboat Letters

Lightning Strikes Again

I have been building and/or repairing boats, as well as cruising extensively on the three multihulls that I built for myself, for the largest part of the last 45 years. In the "Striking Lightning Facts" article in the January 2015 issue, you refer to "multihulls" as if catamarans and trimarans are the same. They are not. Catamarans have a very difficult time achieving the same level of lightning protection as trimarans or monohulls can, partly because they do not lend themselves to having as direct (straight) a route to ground. The problem is that lightning seldom makes a 90-degree turn to follow a catamaran's necessarily bent ground wires. A relatively straight, relatively vertical run of a AWG 00-gauge ground wire is preferred. Hard to achieve on cats, easy on monohulls and tris.

 


 

In searching for an explanation for the apparent attractiveness of multihulls, are there any data which relate strikes to the size of the vessels struck? We see beach cats everywhere, parked in the open with masts rigged, but hardly any monohull dinghies left the same way.

 


Editor: Unfortunately, even with 10 years of data, we're limited by the number of claims in our ability to parse the data beyond monohull/multihull or size category for all boats. We're talking very small frequencies here, and we've gone as far as we can while keeping our results statistically significant. With respect to trimarans, we do have what look to be a significant number that have had lightning claims, but we cannot say that their frequency is more or less than that of catamarans. Similarly, while size clearly matters when looking at all types of boats, we lack the data to say that size matters to multihulls specifically because the sample sizes get too small.

 

The article on lightning reminded me of helping a friend move his Catalina 34 across Lake Huron when an electrical storm came up. He had me get the jumper cables out. I connected them to the shroud and let them run down to the water, just as a precaution. We were glad that it was never "tested." Probably like putting a forest fire out with a glass of water.

 


Editor: We've heard of this solution (or doing the same with chain) often among our sailing friends who swear it has prevented lightning strikes. We wish we could say we have some hard-and-fast evidence to support this approach. But there's no way to tell with statistical accuracy if the boats where this approach was used have been struck less frequently or had less damage than on boats where it was not used. The recreational boating industry doesn't have the funding to get properly controlled, experimental data on lightning strikes. We will be interviewing a number of lightning experts from other lightning-vulnerable businesses — aviation, airports, agriculture (there is a huge lightning problem with grain silos) — and this is one of the things we will ask about. Stay tuned.

 

Regarding what to do if you are caught out on the water: Thunderstorms normally bring high winds. What should you do on your sailboat if you cannot go below, and must stay in the cockpit to maintain some steerage? My sailboat has a wheel, and I have often wondered what I would do in that situation.

Staying in port is always the best course of action, but we all know Mother Nature has a mind of her own.

 


Editor: You absolutely do not want to be holding onto a metal wheel during the storm. What you should do depends a great deal on where you are, what the wave and wind conditions are, and how long the storm is likely to last. If you have an autopilot, taking most of the sails down and just working your way slowly to windward with the autopilot is a good option. If you don't, I'd suggest heaving to and lashing the wheel until the storm passes. On an inland lake with a fairly stable cruising boat, striking the sails and lashing the helm so you lie beam to the wind and waves is fine. But you don't want to do that if the waves might reach a height of half the beam of the boat, because you could risk getting capsized.

Better Bilge Pumps

Top-notch article on bilge pumps in the January 2015 issue! One question: does each bilge pump need its own discharge line and port or can they be ganged together?

 


Captain Lanier: Bilge Pump Systems (22.8.8) states that if discharges are manifolded together, one pump cannot back-feed into or reduce the pumping capacity of another.

That means you can't just use a T or Y to connect them to the manifold, and the discharge manifold must be of the same size or larger than the output size of each pump combined. In other words if you have two 1-inch-diameter pumps, the size of the discharge manifold must be at least 2 inches. With multiple pumps, the required diameter of the discharge manifold can "grow" pretty quickly. My personal preference is for each pump to have its own discharge outlet whenever possible. I think it makes for a simpler installation in the long run, and I like the redundancy it provides (separate, complete systems instead of bilge pump systems with a common potential point of failure).

 

Regarding bilge pumps, it isn't only while you are afloat that you need them. Last winter, a friend had his boat stored on land. It rained hard, and the bilge overflowed with water ruining his teak-and-holly floors.

I store my boat with the mast up. I know water can run down the mast and collect in the bilge. I leave my three AGM batteries installed and aboard the boat. The bilge pump is wired directly to the batteries through a three-way, on-off, manual switch with fuse. I leave the switch on during the winter. The wire connections are at the very top under the floorboards. The bilge is always clean and debris free.

Just before Christmas, I went to check the boat and found the bilge filled with water almost to the top. The connections were fine. The flapper style automatic switch was moving freely. The pump wasn't clogged. The three-way switch was in the on position. What was left to cause the pumps not to work?

The fuse was 18 years old and had failed on its own. Another insurance claim avoided.

 


Marina Safety

I just read the article on covered moorages in the January issue. Our covered moorages are mostly free-floating, so during heavy snows we either sweep or hope that everything comes back up after the snow. With respect to fire, code in the City of Portland, Oregon, requires the plastic panels described in the article over every boat in the covered area. Curtains (partitions of metal roofing running across the covered area) are also required to keep the fire in a smaller area. These curtains are not expensive and work extremely well.

 


And Other Stuff

Interesting piece on the USCG's changes to life jacket classification in the January Small Stuff. I ride a PWC and am required by law to wear a Type III vest (which I do religiously). I'm looking to replace my old vest with a newer version. Curious thing is my old vest comes with a "50-mph impact rating." I would assume this is specially designed for watersports. However, I can't seem to find any new vests with this impact rating. Has the Coast Guard dropped this certification as well?

 


Editor: Chris Edmonston, president of the BoatUS Foundation, told Seaworthy that the impact rating has also been dropped, as it proved problematic to be consistent depending on the type of water sport, the age and size of the wearer, and other factors. Until the USCG releases its new certification guidelines, he recommends buying a life jacket similar to your old one from a reputable manufacturer.

 

The Alert about the powerboat autopilot being hijacked by a steel bridge which resulted in pretty significant damage to the boat reminded me of a similar experience I had several years ago. I was moving my 36-foot sailboat from Lake Charlevoix to Round Lake, heading for Lake Michigan, and was passing through a narrow channel lined with steel bulkheads. I was singlehanded and, after checking for other boat traffic, lined the course up to pass right down the center of the channel and activated the autopilot. I was putting away the docklines and looked up to find that I had veered off course and was heading towards the bulkhead. I had only seconds to react, just barely recovering from impending disaster.

Lesson learned! Magnetic compasses are adversely affected by steel objects, and that does not exclude autopilots.

 


I'm a BoatUS member and ABYC — certified as an electrical technician. In the Alert in the January 2015 Seaworthy magazine, you asked what's wrong in the three pictures. The one to the left has black cables terminated on a stud. The smaller ring terminal with the yellow sleeve appears to be mounted beneath the larger cable to its right. The ABYC calls for the larger lugs to be beneath smaller ones. This is a very important requirement to avoid overheating when lugs are stacked on terminal posts.

 


— Published: April 2015


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