Plimsoll

A fundamental aspect of seaworthiness, but one which a yachtsman may forget, is reserve buoyancy. A square rigger deeply laden with cargo did indeed "batten the hatches" before going to sea, for if a hatch gave way in heavy weather the ship would likely founder. Modern sailing yachts are light, with ample freeboard, and thus can take on a good deal of water before going under.

Samuel Plimsoll (1824 - 1898) was a member of the British Parliament who worked for the safety of mariners, work which led to a law requiring a mark on the side of every British ship beyond which it could not be loaded. The U.S. adopted the practice in 1929 (Load Line Act of 1929), and the Load Line Convention of 1966 has been adopted by almost all maritime nations.

The modern Plimsoll Mark is depicted above. A ship floats lower in fresh water, which is about 97% as heavy per unit volume as seawater, so a ship leaving the Caribean to enter the fresh water of the Panama Canal's Lake Gatun will lose considerable freeboard. It is interesting to note that Winter North Atlantic requires the most freeboard - the most reserve buoyancy - evidence of the awful conditions met by ships on that run.

The bisected circle to the left of the Plimsoll Mark carries the initials of the ship's classification society, whether American Bureau of Shipping (ABS), Bureau Veritas or, in the case of the illustration, Lloyd's Register.

In the U.S., commercial ships greater than 79 feet in length and engaged in foreign trade must have a marked load line, and carry a load line certificate. The actual certification is undertaken by the ABS. U.S. Naval ships are exempt from load line regulations, but they do carry an amidships mark which limits loading. It looks like an asterix.

Professional Mariner magazine gives the annual Plimsoll Award: "The Plimsoll marks on ships today are an enduring testimony to his tireless pursuit of safety at sea. Professional Mariner proudly presents its Plimsoll Awards each year to individuals and organizations that embody the spirit of Samuel Plimsoll." So great was Samuel Plimsoll's contribution to the safety of life at sea.








Tonnage

In England sailors until fairly recently described a yacht as, for example, a "seven ton cutter." That didn't mean a yacht weighing seven tons, but rather a yacht with a useful interior space of about 700 cubic feet, a "ton", as used in that context, equaling 100 cubic feet.

Lots of folks are confused by tonnage terms. Here are the four fundamental measurements.

Gross tonnage measures the interior space of the ship, including most non-cargo spaces. One of these "tons" equals 100 cubic feet. As I understand it, the term is derived from "tun", a great fat barrel holding 256 gallons of water or wine, and requiring about 100 cubic feet of stowage space per tun.

Net tonnage is the useful cargo space of a ship, with again one ton equaling 100 cubic feet. Generally, net tonnage is the ship's gross tonnage minus engine spaces, shaft alleys, crew quarters etc. There are, as the normally very dry Knight's Modern Seamanship puts it, "some annoying variations" among nations in what spaces are disregarded to find net tonnage, but these variations are disappearing in the face of international conventions, including the International Convention on Tonnage Measurement of Ships. Net tonnage is important not only because it describes the cargo carrying capacity of the ship, but because canal fees, harbor charges etc. turn on net tonnage.

Displacement is the weight of the water displaced by the ship, which is, as Archimedes realized, equal to the ship's weight. Generally, not always, yachts are described by their displacement.

Deadweight tonnage (DWT) is a measure of how much weight a ship can safely carry, disregarding the unloaded, unfueled, unprovisioned weight of the ship ("lightship weight") but including not only cargo, but also stores, fuel, water etc. The term is sometimes confused with displacement but the two terms mean entirely different things.

Yacht Names

 I've written about yacht names before, see the January 21, 2010 post. Here are a few that have occurred to me lately. Feel free to use or suggest them - perhaps you'll let me know by comment if you do.


Trice  Trice, an old English usage of uncertain etymology but dating to at least the 1500's, means at once or instantly. It could be the name of a fast cruising boat.

Brant   A brant is a sort of seagoing goose common to New England.Bird names make good boat names - Herreshoff's Meadowlark, Shearwater and countless others come to mind - but I don't think I have seen a transom bearing the name Brant. Brant has a good bold sound, a bit in your face; I like it. 

Tipping Point   Here's a phrase that is very much in vogue just now. Maybe a clever name for someone's first sailing yacht, about which purchase - and use - he is a bit nervous.

Pierhead Jump   A sailor who signs on for a voyage with little forethought and without knowing much at all about the ship or the skipper has made a pierhead jump. It's a good salty name for a boat bought without a lot of deliberation.

What thoughts went into the naming of your boat? Have you lately seen a name you thought was just great? Do you, like me, see my post linked above, think there are rules to the naming of boats, or does anything go? Post a comment!

The Shipping Man

A friend of mine, Matt McCleery, has written a book - The Shipping Man. It's a nice tale of a money manager's sudden infatuation with owning a ship, apparently a disease with no hope of cure. It made me want to be "A Shipping Man" too!


I really liked the book. Good plot, good characters, well crafted, and an education to boot. Here's a link:

http://www.amazon.com/Shipping-Man-Matt-McCleery/dp/0983716307

Lifeboat

 While picking up my son (he who can tie a bowline with his feet) at Massachusetts Maritime Academy, I saw some modern lifeboats and took a few pictures.

Modern lifeboats are completely covered and have diesel engines. The propellers are shrouded in Kort nozzles, for the safety of people in the water.

I like this picture. On cargo ships and tankers the lifeboat is often mounted on rails over the stern, and when the lever is pulled the boats flies down the rails and into the sea. That's a boat you don't want to miss.



This lifeboat has a capacity of 76 persons, each strapped into a padded seat. Not comfy, but a lot better than an open boat.

The steering station. The silver tube to the left of the helmsman is the exhaust pipe.

Peter Arno

Peter Arno was a New Yorker cartoonist in the middle decades of the last century. His cartoons were often politically incorrect - he might have said risque - even then. The top one is from 1941, the priceless bottom one 1949, I think. Enjoy.

Bowline Strength Test - Conventional Wisdom Bites the Dust

My November 13 post was about the "correct" way to tie a bowline. Searching the web, I came across some comparison testing of the correct and incorrect methods (http://user.xmission.com/~tmoyer/testing/pull_tests_11_98.html). The testing was by a member of the Salt Lake City Sheriff's Office, which does a lot of mountain rescue. The protocol looked a little unorthodox but sound (see below). Here is the result of the bowline test:

            11/23 Test #14
              Pull a bowline knot to failure. A bowline was tied in each end of a piece of
              new 11 mm Blue Water rope. One knot was tied "correctly". The other was
              tied "incorrectly", with the tail of the rope outside the loop formed by the
              bowline. The load was applied between the two bowline knots, on a single
              strand of rope.
              Result: Material failure at the "correctly" tied knot at 4840 lbs.

The caveat I will add is that these knots were presumably both drawn up tight before they took a load. Just maybe the correctly tied knot is more stable and less likely to trip while drawing tight, a consideration if - but only if - the line is so big and stiff that it cannot be drawn up by hand - not a common scenario for the yachtsman. Also, with the tail inside the knot the correct bowline is a bit less likely to hang up, if that is an issue.

Here is the testing protocol:

"We used a vehicle winch on a Hummvee to apply forces. A second Hummvee was initially used as an anchor. However, with an end-to-end pull, and with all four wheels locked, we were able to drag both vehicles across the concrete floor with 5000 lbs force. (good number to know if you use vehicles as anchors.) We ended up anchoring one vehicle to a tank (yes - really) and the other to eyebolts mounted in the wall. A Sensotec load cell was used to measure forces. It is calibrated internally with a shunt resistor."

Flashlight holder

I use little Mag-Lites on Journeyman, the ones that take AA cells. The Mag-Lites are rugged, waterproof, bright and focusable, and you can keep one in your pocket at night on watch.

I keep one just inside the companionway to starboard, and I added another to the bulkhead separating the salon from the forward cabin. That new one is almost a spare, but it comes in handy when we are sleeping forward at anchor.

The flashlights come with a ballistic nylon holster. To make a mount, I trim the holster off short with a hot knife, then screw it to the bulkhead as shown, with two short fat screws. It is an effective and easy mount.

Every spring I put in fresh batteries, so the flashlights will be ready for emergency use.

My First Yacht

The New Yorker once ran a cartoon of a fellow lettering his yacht's name - "My First Yacht"- while leaning over the transom. The name was upside down.

I did have a slightly inspired idea for a yacht name, perhaps appropriate for someone new to yachting and a bit nervous about the whole thing. Here it is for the taking:

Tipping Point

How to Tie a Bowline?

My son Willie can tie a bowline with his feet. Pretty good.

A few years ago I sailed to Bermuda with a very accomplished sailor. (Circumnavigated in his 60 foot schooner when in his 20's, in the 1970's.) I tied a bowline in a jib sheet, and he instantly admonished me: "That's the wrong way." Huh?

 I had tied the knot with the tail on the outside of the loop. see photo at right. Tied "correctly", the tail is on the inside of the loop, see left.

Ashley, whose Book of Knots is the ultimate authority, here shows the knot correctly tied. The bowline ends up "correct" when it is thrown into the line, as shown in Ashley's illustration. (If you don't already know this trick, it's a good one to have.)

There are at least two ways any knot can fail. It can fail under load, and it can trip, or fail to attain the correct configuration before the full load is applied. I don't know if the "correct" bowline is more stable before the load is applied or if it is stronger under load - or neither. Anybody know?

Chock

When I got Journeyman both bow chocks were original equipment and a little small for my taste. I have mentioned before that my mooring is exposed (a five mile fetch to the west) and I pay close attention to the mooring tackle. If a bow chock tore out the pennant would likely quickly chafe through on the headstay. So I bought a new, nicely polished bronze chock, slightly oversize I suppose. A high polish is more than a matter of aesthetics: if the casting is burred or rough, chafe will increase.

The chock was an improvement but after a season it it shifted a bit under load, a bad sign.

When I rebedded the deck hardware two years ago I replaced the 1/4 inch (6 mm) bolts with 5/16 inch (7 mm) bolts, which seemed better matched to the forces and to the size of the chock. The bolts are backed by good size washers, and I think I used lock washers too. Everything is silicon bronze, so electrolysis will not be an issue. I am very happy with the installation, which is tight and movement-free after two full seasons.

I use this chock for the mooring pennant and for anchoring. The opposite chock seems ok for dock lines, so I will leave it for now.

Toolbox

Here are five handy items for a boat's toolbox. On the left is a calipers, useful for accurately measuring the diameter of line, standing rigging and bolts. Next is a spool of stainless steel seizing wire, for seizing rigging pins, shackles etc. Then a spool of Teflon tape, so useful in keeping threaded fittings from leaking. Then a bottle of medium strength thread locker (Loctite), good for masthead fittings and other parts that you do not want to vibrate loose. Finally, an extension mirror, for inspecting around the engine etc.

Bungee hatch holder

A good way to hold a cockpit hatch lid open is with stout bungie cord, as shown here. The slight amount of stretch required to get the cord over, for example, a sheet cleat makes it very secure, much more so than using non-elastic line. Also, the elastic bungee will stretch enough to accomodate seat cushions. You can secure the bungee with short fat screws holding finish washers. Just pull a loop of bungee under the finish washer, tighten down the screw and trim the bungee - works great.

Wrench sizes

A great time and temper saver is a list of the wrenches you use for occasional tasks.  Reaching the transmission dip stick ("trans. 11/16 socket") or engine zinc ("9/16 crescent") may require the skills of a contortionist, but at least you know you have the right tool in your hand.

Parts list

These are the parts I use in winterizing Journeyman's Westerbeke 12B engine, a 10 H.P. Diesel. The parts add up - $152.97! I could save a few bucks buying an aftermarket oil filter, but filters are critical and a filter is cheap compared with a worn out or blown engine. The engine has two on-engine fuel filters, the elements for which cost $9.90 and $21.66. Journeyman has two 11 gallon fuel tanks (each in a cockpit locker) and each tank has its own Racor fuel filter - a very nice system, giving redundancy to protect against bad fuel, and providing clean, dry fuel before the fuel even reaches the first on-engine fuel filter. The Racor filters will take out water as well as fine contaminants and are world famous for efficiency, but even on line the best price for replacement elements is $25.00.

There are three zincs, at $4.69 (for the engine's heat exchanger), $10.99 (shaft) and $7.64 (the Max Prop's hub zinc). The heat exchanger zincs last about two years but I replace the shaft zinc and the hub zinc every year.

I already had a spare raw water pump impeller so I didn't buy another; same with the belts.

The rest is non-toxic antifreeze, Sorbies to absorb spilled fuel and oil, and of course the engine oil. I have always used just a gallon of antifreeze, saving a bit for the potable water system and the head, but this year Joe at Portland Yacht Services, who knows Diesel, told me to use two gallons. He also said to be sure the engine was at full operating temperature before letting it take up the antifreeze, to make sure the thermostatic valve was open. You got it, Joe.

 

I generally cut a piece of Sorbie to fit in the oil pan below the engine, where it lives year 'round until replaced. The Sorbie absorbs oil and fuel and rejects water, so it keeps any drips from finding their way into the bilge.

Stove fiddles

Journeyman has a two burner Origo alcohol stove. It is not pressurized but burns quite hot and clean. I am very happy with it. The stove lives in a stainless box which contains spills and is easy to clean. The stove came with gimbels, but I could never get them to work well and I am not sure they are a sound design - most gimbled stoves have an oven and are deep and, you might say, well ballasted.

In any case, I needed fiddles and the solution I came up with works well. In the photo you can see two brass rods, 1/4 inch (6 mm). I cut them about a half inch longer than the box is wide, and I then had a machine shop cut threads in each end for an inch or two. (The service was very inexpensive - less than ten dollars.) I then put two brass nuts at each end of each dowel, and locked them against each other so they are tight. I drilled holes in the stove box to fit the dowels (slightly overlarge) and, by flexing the dowels slightly, fitted the dowels into the holes.

The bottom dowel holds the stove in place, and the top one keeps pots on the stove. The dowels are easy to remove, non-corroding - a good simple design.

Perhaps it goes without saying that the best way to heat water on a boat stove is with a tea kettle. Not only is it efficient and lets you know when it is at the boil, but one can leave unused water in the kettle and stow the kettle in a locker, where it won't spill a drop.  

Tack Hooks

Journeyman was originally designed for roller reefing, but now she has old fashioned reefing, so called "jiffy reefing." When I bought her there was no very good way to secure the tack, and I used to lash the new tack (reef cringle) to the boom with some low stretch line, which took a while and was generally unsatisfactory. Modern booms often have tack hooks with which one can easily secure the cringle, and I decided to fashion one for Journeyman.  You can buy the hook at a good supply store. I secured it to the flange (used with the roller reefing gear) with a stainless steel padeye through-bolted and secured with I think 3/16 inch bolts, backed with washers and secured with Nylock nuts, which are resistant to loosening. The system is easy to use and plenty strong, and it cost little.