[Re: "Chainplates Revisited," PS Feb. 15, 2005] I read with interest your article on chainplates. I hope that readers will not misunderstand the discussion of the failure of the J/109 chainplates as an indictment of the Plexus product line. These methacrylate adhesives are remarkably strong and versatile and have a place in many engineered applications in boat structures.
While a change to epoxy might have been appropriate for the particular design of the J/Boat chainplate, I would have no hesitation trusting a Plexus bond in that application provided the joint design was properly engineered around that adhesive system.
We have selected the Plexus product line for some assembly joints in large yacht structures at Delta Marine where we found that their toughness, fatigue resistance, and ability to bond to dissimilar materials were superior to the epoxies we tested.
Jay Miner (Chief Naval Architect)
Delta Marine Industries, Inc.
[Re: "Eyeglass Quandary," PS Feb. 1, 2005] I have found that the Gath windsurfing helmet with a full-face, retractable visor works well in rain, sleet, and sun. With a thin, warm hat under the helmet, it also keeps your head warm and retains body heat in cool, windy conditions. The helmet also affords some protection from impact (boom bang). There is enough room under the visor for my glasses and they do not fog up due to the large amount of air circulation at the bottom of the visor. The visor can be adjusted to full face, no visor, or anywhere between.
Knocking Networked Systems
Capt. Carl Damm's letter "Knocking Networked Systems" (PS, Feb. 1) hit home with me. Our current boat, a J/36 built in 1981, was equipped, when we bought her in 1989, with a very early networked system—Signet SmartPak. It had a number of engaging and useful features, one being the choice of 1, 2, 4, or 6 items on a single display. Going into Cuttyhunk once in the Elizabeth Islands, we had the depth alone displayed because it was raining and we wanted the really big number. About halfway into the channel, just where it looks like you can't go forward, the masthead wind sensor stopped sending, either speed or direction (I don't remember which). The display stopped showing depth in order to put on a message complaining about the wind sensor. AARGH!
The whole system was vaporized by a lightning strike the following year, and we didn't replace it. I hope the new systems that you are testing these days won't do something that unfriendly.
[Re: "More Practical Websites," PS Feb. 1, 2005] I agree that there are many thousands of useful websites residing on servers around the globe. When talking about weather, however, the best sources of information remain the NOAA sites. Not only are there no pop-up ads, subscription fees, and cookie-selling personal information dealers, but you are at ground zero for all the weather data from which every other site is based.
The mountain of weather products at NOAA can be a little intimidating, but start out at: www.srh.noaa.gov/ and pick a region. From there you have access to detailed forecasts of specific towns, long-term radar animation (which Weather Underground charges for), marine forecasts, and enough additional information to keep the most avid weather nerd happy for hours.
For an entertaining treat, enter a town to select a local forecast and click on forecast discussion under the radar image. This is where you can slip into the head of the meteorologists who are actually creating the forecast for your area and hear their unfiltered, passionate, and sometimes humorous weather analysis.
You rightly included eBay in your article, but users should be careful. What might sound like a bargain on eBay can, due to usuriously high shipping fees, wind up costing more than what would be available through local retailers.
Also, although I've used eBay to good effect, there are too many vendors who ostensibly are auctioning goods, but are, in fact, retailers with firm price tags for new products they're simply clearing from their inventories. It's too bad there isn't an eBay alternative that's exclusively for amateurs selling used goods, which is sort of how the whole thing began anyway.
["Teak Treatment All-Stars Finale," Feb. 15, 2005] I had used Skipper varnish for several years with good results, thanks to your ongoing tests. But when I visited West Marine in New Orleans to restock my cabinet, I spotted the dreaded "New Formula" label on all the Skipper cans. An inquiry with the friendly guy in blue shirt and khaki shorts confirmed that the "New!" Skipper product was indeed produced by a different manufacturer. The blue shirt claimed to have no idea who now made Skipper varnish, and his downturned smirk was less than reassuring. He also declined comment on how the "New!" stuff might compare to the earlier formula tested by PS.
I attempted to uncover which manufacturer produced the extinct West Marine Skipper varnish, but none of the usual suspects would confirm or deny their involvement. Because the cost of varnish is tiny compared to the value of my time, I moved on to the Epifanes product also recommended by PS. It was nearly twice the price, but I'd rather be safe than sanding.
New Otleans, LA
Back in 1994, when we tested West Marine's Skipper Varnish, it was made by Z-Spar. Then, when we tested that same varnish (same name anyway) in 2001, it was made by Kop-Coat. It's not surprising that West Marine would change its suppliers as Z-Spar and Kop-Coat—along with Pettit, and Woolsey—are all owned by an enormous conglomerate called RPM. This is the same company that owns Rust-Oleum, Dap, Zinsser, and many other products that sailors have likely used or still use. By the way, Admiral's Varnish is the same as the old Flagship varnish, which was made by Z-Spar, who else?
[Re: "Sea Anchor Test," PS Feb. 1, '05] Although it is not an inexpensive publication (and may have been updated), my 1995 edition of The Sea Anchor and Drogue Handbook by Daniel C. Shewmon was well worth the money. I suggest it to any of your readers who are interested in the results of a series of tests, data on line stress, and the like.
Oh yes, all sailors should remember Mr. Shewmon's warning that "Ground anchor rode length is related to depth; sea anchor rode length is related only to wave height."
C. Henry Depew
["Belt-Style PFD Test," PS Jan. 15, 2005] Thanks very much for the review of belt-style inflatable PFDs. I found it to be very useful when choosing a USCG-approved replacement for my eight-year-old, non-approved inflatable.
As a career Navy Pilot, I have long used inflatable PFDs (Naval aircraft occupants and flight deck personnel wear them at all times), and know several people whose lives were saved by these devices.
There are a couple of other factors that should be considered when choosing one of these devices. First, you may want to avoid wearing automatic inflation PFDs while inside the boat's cabin. Should something catastrophic occur, causing the cabin to flood before you get out, auto-inflation of your PFD may further impede your ability to escape. For this reason, the Navy forbids the use of auto-inflation PFDs in aircraft not equipped with ejection seats.
Secondly, should the CO2 cartridge fail to inflate (or fully inflate) the PFD, use of a manual inflation tube to do so is not easy even in benign conditions. As part of our water-survival training, Navy aircrew are required to swim/tread water for five minutes in full flight gear before inflating their PFDs via the manual inflation tube. Even though this is done in a heated pool with no wind or waves, and most aircrew are young and physically fit, a significant number fail this test. Similarly, I suspect that many average sailors would be unable to do so after treading water for a couple of minutes while wearing a set of foul weather gear.
Green Cove Springs, FL
Congratulations on your article about belt-style PFDs. What was so impressive was that you put the caveat up front. I consider those PFDs worthless because they do not help an unconscious or injured crew member who goes overboard, and they will not be useful for a non-swimmer or someone who panics when they go overboard. Non-automatic ones are even worse.
I insist that everyone aboard wear a PFD when in the cockpit or on deck. We all have auto-inflatable Sospenders units. My policy stems from the fact that I've been in a man overboard situation in a storm at 2 a.m without PFDs.
We had anchored in a harbor in Maine. A terrific storm with 30-knot winds dislodged the anchors on the entire fleet in the harbor and boats were everywhere. My companion and I were sleeping in the cockpit when the storm hit; we grabbed foul weather gear and went to work. My friend went overboard and I didn't know it until I heard a little voice at the stern quarter. I threw him a line and he was able to get aboard.
The big lesson was, no matter what, if you have a nighttime emergency, the PFD goes on first, the harness and tether second, and then foul weather gear, if needed. I am not a fan of the manual inflatable PFDs for the same reason I don't like the belt style. If you are unconscious or injured, can you pull the cord?
Santa Monica, CA
Ceramic Heaters Explained
[Re: "Portable Cabin Heaters," PS Jan. 15, '05] You requested an explanation of ceramic heaters. It happens that I understand them because I researched multi-megawatt heaters for an aerospace propulsion (scramjet) research application some years ago.
Ceramic material has the property that its resistance increases nonlinearly with temperature in a way that is similar to metallic conductors, except that with ceramics, at a certain temperature, the resistance suddenly increases at an almost infinite rate, basically acting like an open switch. The really neat part is that this temperature is hot enough to provide a significant amount of thermal energy transfer, and yet low enough that it will not ignite combustibles such as cloth, paper, and etc., if they come in contact with the ceramic.
There is no need to externally change the voltage or current in this device, which greatly simplifies the electrical heating control circuitry. In operation, when 110-V AC is applied to the input of the ceramic heater assembly, there is an inrush current that rapidly heats the ceramic toward the maximum (cutoff) temperature. As the ceramic temperature rises toward cutoff, the resistance will rise very rapidly, cutting the current back to a level that will just maintain the maximum temperature. These characteristics make the ceramic resistive material self-regulating and, happily, the cutoff temperature is below that of the ignition temperature for paper or other easily combustible materials such as cloth or rugs, etc.
To provide sufficient output power, it is necessary to have a variable-speed fan that will provide enough airflow over the ceramic discs or plates such that the maximum thermal power output can be reached. In essence, the fan must be powerful enough to cool the ceramic enough so that its temperature will decrease to a level that will provide a decrease in electrical resistance to a level corresponding to the maximum rated power output of the heater (which is1,500 W). If desired, lower fan speeds will provide smaller temperature decrements and therefore reduced thermal power outputs as required.
Unlike metallic resistance heaters, this type of device is intrinsically safe, since, if the fan were to fail, the electrical power would instantly decrease to the very small level necessary to keep the ceramic at the safe maximum temperature.
Your test results appear to be consistent with the operational principles I've described. To wit: The output temperature of the ceramic heater will be lower than that of a metallic resistive heater since the heating element temperatures are significantly lower. Metallic heater elements will be upwards of 1,500° F (red hot), while the ceramic will be closer to between 200° and 300° F.
Since the thermal output power (thermal Watts output are proportional to air mass flow times BTUs per unit mass) of any air heater is the product of exhaust air temperature and the air mass flow, the air velocity will be higher with the ceramic heater since the air temperature is significantly lower than in the metallic resistive heater. The quantity of BTUs per unit mass increase with increasing temperature (SCFM x BTU per SCF = BTU/minute. One BTU/minute is a little over 17.5 Watts)
...Where Credit Is Due
To Magma: "I recently had trouble removing the burner from my 12-year-old Magma gas grill. After an e-mail letter to the factory, they asked me to return it to them for examination. Magma's service department removed the old burner and replaced it with a newer design. They also replaced the grease-catch pan and radiant screen—all at no charge! They are fantastic, and offer great customer service and product support." (www.magmaproducts.com)
Chester Springs, PA
To CDI: "I brought the Flexible Furler from my Seaward 24, which I had bought used, to the company's facility because I was having trouble with the halyard. The furler was more than 10 years old, and perhaps as much as 15. The technicians there determined that the halyard was an experimental design that had been discontinued and they replaced it for free. In addition, they re-machined the sail feed slot so that the luff tape would not jam, and supplied me with a couple of pins that had been misplaced by the former owner. This was extraordinary service, given the age of the system." (www.sailcdi.com)
To Professional Mariner: "I noticed an auction of a Professional Mariner battery charger on eBay that was offered without an owners' manual. I inquired via the company's website (www.pmariner.com) regarding a manual for the model I wanted to bid on, and within a day I received an e-mail from the customer service department with a PDF file containing the complete, six-page manual. No charge!
"It gets better. I won the auction, and when I received the charger, not only was the manual missing, but also the boots that protect the connectors (both AC and DC). I contacted Professional Mariner again about buying some boots, or to see if they could steer me to a source for them. Again, within a day, Allan Butler from Professional Mariner's customer service department replied via e-mail to say that a pair of protective boots were on the way to me. No bill, no charge, not even for shipping. Next time I want a battery charger, battery isolator, or anything else that Professional Mariner sells, what company do you think I'll consider first?" (805/644-1886)
To Seco South Riggers: "Hurricane Charley finished off the original lifelines on our Beneteau 390 (and several stanchions ) when the boat fell over in the yard. Beneteau recommended Seco South Riggers in Largo (just outside of St. Petersburg). I called and got a quote. I took the old ones to them to ensure a good fit, and so that they could use whatever existing hardware they could. While in their shop, I noticed several well-known retail names on boxes and buckets (chain and rode) they made up for others, I also noticed a clean and well organized shop area. Jean D'Alessandro was extremely helpful and clarified all measurements and my needs. I received the lifelines back via DHL in the same week, and the cost was under the estimated price. They fit perfectly. This kind of service deserves notice." (727/536-1924)
Punta Gorda FL