Prop Pitching In Comfort
Just read "A Pitch for Adjusting Pitch" in the Offshore Log of the August 1, issue, and it makes me once again ask why some good ideas just don't catch on. Our sailboat is powered by a Saab Model G 10-hp single-cylinder diesel, which came with an 18" variable pitch propeller. By variable pitch I mean variable from the cockpit, not by hauling the boat or going over the side.
Pitch control for us is an integral part of motoring. In the marina, we set the rpm and adjust speed by changing pitch. Reverse is just pitching the prop in reverse, without touching the throttle. In calm conditions we set a deep pitch; for heavy seas we flatten the prop. Our greaser is located in the engine box: give it a turn and it sends fresh grease into the propeller hub without the need for anyone to go over the side. The stuffing box is also grease-lubricated, so no water ever drips in.
Our 32-foot wooden-hulled sailboat displaces 16,000 pounds, but the Saab moves it at 6.4 knots in calm water. We have motored into 40-knot headwinds with steep Lake Michigan waves at five knots. All this and it burns only 1/2-gallon per hour at full throttle!
I wonder why you don't see more like it.
Thanks for all the good work.
-Tom Wetherbee, Engineer
Nick Nicholson's pitch for the MaxProp VP is really an illustration of a Belgian car mechanic's complaint about English cars: "Why is it that when they have the choice between a simple solution and a complicated one, they always choose the complicated one?" The Scandinavians have used the variable-pitch propeller on boats and ships for more than a century (it's pretty much like a hand shift on a car—you turn a wheel and the pitch changes, and you can even change it to reverse without having a reversing gear.
Another element that Nick forgets to mention is the area of the prop's blades: I have two 15-by-9 inch props for my boat, one a Federal "Sailer," a narrow-bladed two-blade prop, and the other a Michigan Wheel wide-bladed two-bladed one. The wide bladed Michigan gives me about 1/2-knot more speed at 2,100 rpm of the Volvo than the narrow-bladed one, but the engine cannot reach its top 2,600 rpm with it. It's the one I put on when I go for long cruises, since I get more miles per gallon with it.
[Re: "Strippers and Crimpers," August 15] On page 12, column one, in of the "Do's and Don't's", the phrase "voltage resistance" appears. This is not correct usage. What you should have said was simply "resistance." Or you could have said "the resistance will cause a voltage drop or loss."
Another point: The crimping tools you review do not include the best available tool for use on boats in cramped spaces, namely the Thomas and Betts tool. And the tools you recommend for "just a few crimps a year" cannot make good, gas-tight crimps.
-William F. Steagall, Sr.
ScB, MIT Electrical Engineering, 1951
The web address for Thomas and Betts is: www.tnb.com.
-Hard Knox Editor School, 1972
3-D Riding Sail
Regarding a three-dimensional riding sail [PS Advisor, October 1], perhaps Harlan Fredericksen was recalling a post I made in the "rec.boats" Internet newsgroup about 12 years ago. I described (including an ASCII drawing) a simple tent-like rig which used a square cloth with lines attached to grommets at the four corners. One should experiment, but the square side may be about 20-25% of the boat length. On a sloop, one corner is attached to the boom, roughly at the midpoint of the boom. The diagonally opposite corner is attached up the backstay, pulling the diagonal tight about 40 degrees above horizontal. The diagonal can be reinforced with a guy running under the material from boom to backstay. The two dangling corners are then made fast to the respective stern corner cleats or other attachment points of convenience so that the sides form a roughly 50-degree included angle. The rig looks like a lean-to tent with the opening looking aft.
I used this first on a 17' Thistle, then on a 26' ketch, both of which otherwise tended to sail at anchor. I received two e-mails from persons who tried it with success after my post. I've been meaning to try it on my 43-foot sloop but the boat doesn't behave badly enough for this to be a priority. The rig does not slat, does not sail, is relatively simple, and cheap.
The idea came from a type of fin the Germans experimented with on an anti-aircraft missile prototype during WW II. A friend had dug this out of the literature for our rocket club project back in the '50s.
Punta Gorda, FL
Steve and Linda Dashew's Bluewater Handbook (1984) shows a pair of twin riding sails on a split backstay, with both tacks cranked down to a strong point on the centerline to form a forward-facing wedge shape. They used two 15-sq-foot sails this way on Intermezzo II.
The Dashews also recommend the use of full-length battens to reduce chatter, and suggest that the riding sail should be about 8% of total measured sail area.
I intend to try the mizzen this way in my newly acquired ketch, but haven't done so yet.
-Silver Donald Cameron
D'Escousse, NS, Canada
The three-dimensional riding sail pictured on page 69 of Heavy Weather Tactics Using Sea Anchors and Drogues, by Earl R. Hinz is, I believe, what Harlan Fredericksen was referring to.
Keep up the good work.
Channel Islands, CA
Self-Rescue By Ladder
Like so many articles on crew-overboard recovery, the PS Advisor in your October 15, 2003 issue describes a variety of sophisticated, dedicated, and somewhat complex devices for crew recovery. Our Valiant 39, Ocean Explorer, carries a full complement of such devices on its pushpit.
This past summer we had our first real-life experience in recovering people from the water. We encountered three adults and a child whose open runabout had swamped and sunk in steep, six-foot seas on shallow Lake St. Pierre in the St. Lawrence River. They were sighted at the edge of the shipping channel and were about to be swept into shallow water by the two-knot current. We had one chance to recover them before they would be in water too shallow for us to enter. There would be no opportunity for us to use our Lifesling as it is recommended, and certainly no time to pull out four people with a block-and-tackle. Therefore, we simply pulled up next to the group and deployed our rail-mounted boarding ladder. In spite of the steep, breaking seas and being in the 65-degree water for over a half-hour, all four rapidly climbed up the ladder and onto the deck. As a friend said, "You cannot imagine the motivation that people have when they think they are going to die."
My point is this: It is important that every vessel carry the more sophisticated equipment described in your column. It has a very important place in the recovery of the injured, hypothermic, and/or exhausted crew member. But, the ability of the crew-overboard to self-recover is too often overlooked in such articles. In my opinion, every vessel should have a device, whether it be a boarding ladder, stern swim platform, or swim ladder for crew-overboard self-recovery when that is possible. And, this device should be specifically mentioned as one of the important pieces of crew-overboard recovery devices in articles dedicated to such recovery.
-Richard A. Fink
Back to School
I've just received my October, 2003 issue, with, among others, the article by Nick Nicholson, "Back to School."
I am training officer for the Halifax Squadron of the Canadian Power and Sail Squadrons. (If you don't know us, you certainly do know our American cousins, the US Power Squadrons). This article is just the sort of thing I'm always looking for to encourage people to take our courses on Piloting and Navigation, and safety in general. I'd appreciate permission to copy this article, to offer to students enrolled in our beginning courses, to encourage them to take more advanced courses.
Halifax, NS, Canada
Your Offshore Log, "Back to School," is right on the money. As a U.S. Coast Guard Auxiliarist I teach "Advanced Navigation," as well as the "GPS and Electronic Navigation" class. Invariably, at the beginning of these classes, students ask whether they really need to do all this plotting work on charts with pencil and parallel rulers. Your article is an excellent real-life description of an electronic failure, and a good example of why a manual backup to the electronics is necessary.
Would you allow me to copy the article and hand it out to the classes?
U.S. Coast Guard Auxiliary
District 11NR, Flotilla 1-5
See this month's Offshore Log for more feedback on the October 1 article.
My boat is a '78 Catalina 30 that had a Norcold front-door refrigerator, which finally died. The by-now 24-year-old Norcold's insulation had absorbed so much moisture that we had to saw the thing out. It had swollen about an 1" wider than the original cutout and was several pounds heavier from the moisture.
I looked into retrofitting the area it was built into with a top-loading model (either drop-in or custom) but for the overnight or occasional four-day trips I take it wasn't worth the effort and cost of a converting it to a top-loading box.
I resolved that I would install another front-loading refrigerator and started shopping. I became intrigued with Isotherm's "ASU" (Automatic Start-Up) units. The idea is much like an engine-driven holding plate system. When the unit sees voltages indicating a charging current is available (such as from shore power or the engine's alternator) the Danfoss compressor kicks into high gear to chill the holding plate. When charging current is not available, the compressor runs at a lower rate to save energy. If the holding plate is still cold and the fridge is still cold, then the compressor doesn't run at all.
As of this writing it has worked well enough that I thought it would be worth mentioning to you. I don't have a battery amp-hour meter with which to tell you any specifics on energy savings, but my experience is showing that I'm not draining the batteries to the extent I normally do. Since everybody's scenario on how a refrigerator will be used will differ, I'll outline how I use mine so that you can take this in context.
The refrigerator is left off with the door open when we are away from the boat.
As soon as I return to the boat, I turn on the fridge. It is still on shore power, and the compressor runs in high mode during this time to freeze the holding plate. This can be anywhere from 15 minutes to a couple of hours before I'm off shorepower.
Motoring out of the marina takes about 15 minutes before I have the sails up and shut down the engine (an 18-hp Universal with standard 55-amp alternator). During this time the fridge's compressor is still running in high mode to freeze the holding plate.
Typically we sail to Catalina (California) and spend one to three nights there. During this sailing time the fridge's compressor is in low mode, if it is running at all (depending on how well the holding plate is doing).
The engine is back on during anchoring or picking up a mooring. This is commonly about 20-30 minutes.
Each morning we run the engine to recharge. At this point the batteries are now somewhat depleted (we run four 6-volt golf cart batteries for the house system) and there is some competition between charging current for the batteries and the fridge, but this seems to be more than offset by the fact that the batteries are not as discharged as they used to be with the original fridge. Sometimes I'll turn off the fridge to let the batteries get the full charge during bulk acceptance phase, and then turn it back on a bit later.
The observation I have at this point is that I haven't heard the fridge run much at night, if at all. The holding plate seems to have been chilled down enough during shore power and motoring that the compressor isn't kicking on much. However, the real test will be next summer as these experiences have been during our cooler season (only about 75° F belowdecks during the day & 65° F at night). There are usually two to three adults on board, and we like to cook a lot while on board, therefore we are in and out of the fridge a fair bit.
Dana Point, CA
Your article on the boat heating systems was obviously just a quick overview of the various options available, without your usual in-depth evaluation of the products. However, I think you really "missed the boat" regarding your Wallas heater comments. First of all, there's no way the heater uses 1/4 to 1/2 gallon per hour—it's more like 8 hours per 1/2 gallon. I have the 30D in a well-insulated 40' sailboat and it heats beautifully.
The Wallas is a wonderful heater for many reasons: very little current use after start-up (which is important when sitting at anchor for extended periods of time), low fan and exhaust noise (no Espar jet engine noise), fits into small spaces, is easy to install yourself, and isn't as costly as many of the other units.
I think you would do your readers a real service to do an in-depth examination of the forced-air heaters available for boats. In my opinion, forced air is the right way to heat a boat, but some units do it better than others.
I have no connection with Scan Marine or Wallas heaters.
You're right about the fuel consumption. The Wallas 40D Nautic consumes only 0.12-0.42 qt./hr. The 30D consumes .026 - 0.7 qt./hr., according to the Scan Marine website.
I have an Origo Heat Pal on our sailboat up on Lake Granby, Colorado (8,300' elevation). I found out that it will get hot as time goes on, and the flames will rise higher and higher as the alcohol gets hot and vaporizes. I used to set it on the teak and holly sole of our Compac 23/II. Now I have a 1/8" thick aluminum plate that is about 13" wide by 20" long. This plate lies on the teak and holly sole now, with the Heat Pal on top of it. This takes the heat from the canister and keeps the flames from flaring up and causing the temperature in the boat to rise to 95° F.
We have a CO detector since the boat is somewhat closed up when the temperature gets down to 30° F in the night.
We have found that the alcohol needs to be fresh and not have water in it to keep the bad-smelling fumes from tearing up your eyes. The brand that comes from Cut and Shoot, TX seems to be about as good as it gets.
I’ve found a very successful method of heating a cold boat in the morning in order to coax my wife out of the berth.
It's an indoor-safe propane heater called "Mr. Heater, Portable Buddy" that uses the one-pound propane tanks and has a radiant element. I cruise the coast of Maine summers, and often mornings are in the 50s or lower. This heater will warm the cabin of my 35' Island Packet to 70° F or better at a rate of about 10° F per half hour. Not bad.
I've been informed that this heater is very popular with Alaskan fishermen. I believe it. Check it out at: www.mrheater.com.
-Trump Bradley Granville, OH
...Where Credit Is Due
To Kappa Sails, Westbrook, CT: "Kappa Sails are the heart of our Mason 33's upgraded sail system. They significantly improve our boat's performance and handling. They are stunning—so much so that other boats often change course to hail us and inquire, 'Who made them?'
"But that is not the full story. One year after the sails were installed Kappa Sails called to report that evidence was developing that the Kevlar-reinforced material that had been used to make our genoa had a manufacturer's defect. Loft owner, Clarke Bassett, made an appointment to inspect the sail himself, and together we determined that premature loss of shape had begun to take place. Clarke even brought a camera to document the change. Rather than try to prorate my year's use of the sail (as some sailmakers would do), and rather than waiting for the fabric manufacturer to settle Kappa's claim with them (as some would do), Kappa offered to replace the sail at no change. Several attempts on my part to compensate him in some way for his trouble were refused, and a new, equally beautiful and functional sail was delivered and installed on the boat at no cost. Since then, the genoa and main have continued to meet and exceed our every expectation. We strongly recommend Kappa Sails to anyone wanting the best in quality and customer support."
La Grange, IL