Saturday 30 April 2011

Spring Lines for Berthing/Docking Sailboats and Yachts

Trouble free deployment of spring lines when mooring and docking your sailboat is a most important part of your skills set toolbox as a professional and competent skipper. As in all things, practice makes perfect and as just about every docking situation throws up a different set of conditions; wind, tide, other craft in the vicinity, currents etc. it is good practice to learn this process thoroughly, so that embarrassing incidents don't happen when the whole world is watching! In my ebook 'Voyage of the Little Ship Tere Moana' I write about several incidents where unusual techniques were used.

The following is an extract from and has some useful tips for trouble free mooring and docking:

Using Springlines to Tie up to the Dock
When a boat is docked where the tide will go up and down, there are several ways to ensure that dock lines remain relatively tight and the boat does not move forward or back along the dock in the wind or current. This ensures that fenders will remain between pilings and the boat, rather than hanging uselessly as the boat rubs directly on the piling next to the fender.

Floating Docks with Sliding Tracks if Available
The easiest way to deal with tide changes is a floating dock. The boat can be tied tightly to the dock and it will simply ride up and down with the dock. Some docks are equipped with sliding tracks on the pilings, and the boat can be secured with a short midship breast line to the slide car, which will move up and down with the tides. Other lines are still needed to prevent the boat from swinging, but the short line attached midships to the piling will prevent fore and aft movement. In other cases, there are pilings all around the boat with sliding rings around them or some other method of allowing the rope attachment point to slide up and down with the tide. Docks with these accessories are the easiest to tie up to, but they're not readily available everywhere you might want to tie your boat up.

Spring Lines for The Rest of Us
Most of us don't have any of that fancy stuff, but need to keep our boats riding up and down on one or two pilings, and do not want it to move enough to allow the fender to miss the piling. That means the boat can move forward and aft only the length of the fender (if hung sideways) or fender board set that rides on the piling. So how do you tie up the boat so that it remains in one place at the dock, despite changing tides, winds, and currents?

The answer is to use spring lines to prevent fore and aft motion, and long bow and stern lines to prevent the boat swinging in and out. It also helps to attach dock lines to cleats or pilings that are at the same level as the cleats on the boat at mid tide, if this is possible.

Once a boat is pulled in alongside a dock and some temporary lines are run to keep it from getting away, the first decision to be made is which piling(s) the boat will lie against. This will depend on the spacing of the pilings and the shape of the boat. If pilings are widely spaced and the hull is curved inward at the bow and stern, as in most sailboats, it may be best to set the boat to ride against one piling amidships. If pilings are spaced more closely, it is usually better to plan on having the boat ride against two or more pilings, each insulated from the hull by a fender or fender-board set. The first diagram above illustrates two possible scenarios.

Using one piling or two:
The sailboat (left) lies against one piling. The sailboat has no midship cleat, so spring lines are run from a bow cleat leading aft and from a stern cleat leading forward.

The powerboat (right) lies against two pilings, and has a midship cleat. Spring lines are run fore and aft from that cleat to pilings off the bow and stern.

A boat with properly tied spring lines, and one with improperly tied spring lines:

A boat with properly tied springlines at low tide and high tide. The lines are attached to the piling at the level of the boat during a medium tide, so that they rise up to the boat for high tides and fall down to it for low tides.

More on Docking and Fenders:
The boats are held in place by long spring lines. In the case of the sailboat in the diagram, there is no midship cleat, so spring lines are run from a bow cleat leading aft to a piling adjacent to the stern, and from a stern cleat leading forward to a piling adjacent to the bow. The powerboat in the diagram has a midship cleat, and spring lines can be run forward and aft from that cleat to pilings off the bow and stern of the boat.

Controlling Fore and Aft Movement of the Boat:
These lines will prevent the boat from moving forward or aft, keeping the fenders (which are hung from stanchions or lifelines on most boats) in place between the pilings and the boats. As the tide goes up and down, the long spring lines can remain fairly tight, since their angle to the dock (and consequently their length) will not change significantly.

The two spring lines (shown in red in the picture) do a great job of preventing the boat from sliding forward and aft along the dock, but they do next to nothing to prevent the bow and stern from swinging in and out. To do that, it is necessary to attach bow and stern lines, and those lines should also be run as long as possible, to pilings set far forward and astern of the boat. With short bow or stern lines attached to nearby pilings, the tidal changes will result in too much slack at high tides, and/or the boat hanging from taut lines at low tides.

Longer bow and stern lines set to pilings further away from the boat can be tied more tightly for the same reason long spring lines work well with changing tides: the angle to the dock changes less as the line used is made longer, so the length of the line can remain virtually constant through tide changes.

The powerboat in the illustration has a stern line attached to an outside cleat on the stern of the boat rather than to an inside cleat, which is another way of using a longer line and getting a better angle to the dock. The bow and stern lines are not as long as the spring lines, particularly in the case of the powerboat in the illustration, and must have a bit of slack to account for tide changes, but they will still prevent the boat from swinging out from the dock too much.

Properly Tied Spring Lines and Bow and Stern Lines
A view from the side shows how a boat with properly tied spring lines and bow and stern lines will look at low tide and high tide. Note that the lines are attached to the piling at the level of the boat during a medium tide, so that they rise up to the boat for high tides and fall down to it for low tides.

Lines Too High
The next illustration shows a boat with the lines connected too high on the pilings. At low tide, the lines are taut, and the boat will sit still at the dock. At high tide, however, the boat has risen up toward the points where the lines are attached to the pilings, and the bow and stern lines are slack. With the much longer spring lines, as you can see, it makes far less difference if they are attached at the wrong height on the piling. The shorter a dock line must be, the more important it becomes that the line be attached to the piling so as to be level with the boat cleats at mid-tide.

With properly set spring lines and bow and stern lines, any boat can be made to rest alongside a piling or set of pilings. Properly deployed fenders or fenderboards will protect the boat from the dock no matter what tide, wind, or current condition may come along.

Article courtesy

You can read more about anchoring and docking with some humourous outcomes in unusual and far away places in my ebook 'Voyage of the Little Ship Tere Moana' downloadable from my website    

Wednesday 20 April 2011

Sailboat Running Rigging Lines and Ropes for Cruising Sailors

Replacing the running rigging on your boat seems like it should be fairly simple, and a decade or two ago, it was. As with electronics, safety gear, and even sails, technology has significantly improved cordage. The downside to all these improvements is that not only are there more options then ever, but you may feel like you need a materials-science degree in order to choose the right line for your new jib halyard. Here, we’ll take a look at what the newer, high-tech materials can do for your boat.

When it comes time to choose new rope for the lines aboard your boat, you’ll need to consider the type of sailing that you’ll be doing (a year in the tropics? racing to Bermuda?), the hardware that you currently have (clutches, sheaves), what qualities you feel are important (soft hand, ease in splicing, weight, durability), and your budget. The type of sails you have is another consideration. “If you’ve already made the investment in laminate sails, then you should really consider upgrading your running rigging to a low-stretch material,” says Brian Fisher of Rig Pro, in Portsmouth, Rhode Island. “But even if you have Dacron sails, you can benefit from a cordage upgrade.”

Starting at the top, you should check over your sheaves before replacing your halyards, and if you’re going from wire to rope halyards, you’ll need to change to rope sheaves. (Wire halyards use a V-shaped sheave; rope sheaves are U-shaped.) While you’re aloft, look for any sharp edges that could chafe through your new line, especially if you’re going from wire to rope halyards.

There are plenty of choices for new halyards, from basic polyester double-braid to all the high-tech materials. Whatever you choose will probably be a compromise between such factors as amount of stretch, cost, weight, and ease of handling.

Long the workhorse on many a cruising boat, polyester (Dacron) double-braid is still a good choice for many onboard applications. Polyester is long lasting, resistant to ultraviolet radiation, and costs a fraction of high-tech rope; however, it’s somewhat stretchy and heavier than more modern materials, and if there’s one area on board that could benefit from an upgrade to lightweight low-stretch line, it’s the halyards.

Most cruising boats have a roller-furling headsail, and many have in-mast furling mainsails as well. Since these remain hoisted for possibly months at a time, a lightweight low-stretch line will offer better halyard tension and sail shape over the long run. This is true for non-roller-furling sails as well, especially if you’re heading out on a long passage where the sails will be set for a while. Here Fisher recommends using a Spectra/Dyneema-cored line, since it’s extremely strong, lightweight, and doesn’t absorb water. An alternative would be a Vectran-cored line, which stretches even less and doesn’t creep; however, it’s heavier than Spectra/Dyneema and absorbs water. When switching from polyester to a high-tech line, it’s usually possible to downsize the line by a few millimeters since these fibers are so strong. This is a definite advantage for bigger cruising boats, since polyester line can be quite bulky at larger diameters.

If the price tag of Spectra/Dyneema-cored or Vectran-cored line is a little steep, all the major rope manufacturers currently make “mid-level” blended-core ropes that would be well suited to the cruising environment (and easier on the wallet). A few examples are New England Ropes’ VPC, with a Vectran and polyolefin core, and T-900, with a Dyneema and Technora core; Samson’s MLX, featuring an Innegra-S and Dyneema core; and Yale’s Aratech, with a Technora and Spectra core. Both high-tech lines and the mid-level blends typically have polyester covers, which provides extra U.V. protection and a nice hand, although there are also covers available that blend the polyester with materials such as Technora, for its abrasion-resistant and heat-dissipating qualities. If weight saving is a major issue aboard your boat, note that many of the high-tech ropes available are core dependant, and the cover can be stripped off. On the majority of cruising boats, however, the effect would be negligible.

Like halyards, sheets are an area where Spectra/Dyneema-cored lines can improve performance and even your sailing experience. “Since you can downsize your line when you switch from polyester, you end up with smaller, lighter piles in your cockpit and less weight pulling at your sail,” says Fisher. He offers an example of genoa halyards on an Oyster 46, which are 69 feet long. In this application, polyester double-braid lines would measure 3/4-inch in diameter, with a breaking strength of 16,000 pounds and a weight of 11 pounds. A Spectra/Dyneema-cored line would have a 1/2-inch diameter, a breaking strength of 20,000 pounds, and a weight of only 4.6 pounds. And only the polyester cover would absorb water, offering additional weight savings as well as more pleasant tacking.

It’s worth noting that if you’re replacing your running rigging, the time’s right to inspect your deck hardware, too. Since polyester line has more give, it absorbs more of the load from the sails. If you make the switch to high-tech line, be sure that your deck hardware is appropriately sized and reinforced.

Spinnaker sheets are well suited for a high-tech upgrade as well, since a lightweight, small-diameter line that’s also very strong will offer better performance. Examples of good choices for this application are Samson’s WarpSpeed, featuring a Dyneema core and a polyester cover, and New England Ropes’ Flight Line, which has a Dyneema core and a polypropylene cover.
Rope construction for the mainsheet is much a matter of personal preference. Single-braid is usually softer, has a nice hand, and doesn’t kink, but it could snag more than a double-braid line and doesn’t have the additional abrasion resistance of a cover. Yale Cordage’s new Ph.D. rope, introduced in 2010, is a single-braid construction made from polyester-coated Spectra. According to Yale, the polyester coating gives the rope a nice feel and good grip on winches, while the Spectra core gives it strength and weight savings.

All the Rest
While halyards and sheets have been the focus here, there are plenty of other places aboard that could benefit from a high-tech makeover: runners, the outhaul, the traveler, the boom vang, even lifelines. If a major high-tech cordage upgrade is in your future, it may be wise to consult with a rigger to ensure that the chosen material is suitable to the application on your particular boat and that your lines are appropriately sized. “I’ve seen several situations in which customers have forgotten to take into account proper line size with regard to the winches and rope clutches on their boats,” notes Andrew Spiro of The Ship’s Store and Rigging, in Portsmouth, Rhode Island. “It’s simple, but just because you can use a smaller-diameter line with the same strength, they forget that the winches and clutches are limited to certain sizes. The result is often slipping.”

Always on the forefront of technology, raceboats have been using high-tech fibers for years in many applications on board, even standing rigging, and as these fibers have improved and their acceptance has grown, more and more wire is being traded out in favor of these lightweight alternatives. Cruisers can also reap benefit from these advances.

The Right Stuff for ropes
Aramids (Twaron, Technora, Kevlar): Like other high-tech fibers, aramids are strong and stretch little, but they also have the benefit of being resistant to heat. You’ll find aramids in both double-braid cores as well as blended with other fibers in the covers.

Dynex Dux: A relative newcomer to sailboat rigging, Dynex Dux is pre-stretched and heat-treated Dyneema. This process, however, produces an extremely strong rope with virtually no creep that is suitable for service in standing rigging.

H.M.P.E. (Dyneema, Spectra, Amsteel): High-modulus polyethylene has many benefits for running-rigging applications: It’s very strong, lightweight, doesn’t absorb water, has decent resistance to ultraviolet radiation, and it can float. On the downside, it has more creep (see “Rope Speak,” page 80) than other high-tech fibers.

L.C.P. (Vectran): Liquid-crystal polymer fiber possesses high-strength and low-stretch qualities and suffers virtually no creep. L.C.P. is one of the strongest core materials, although it doesn’t have the U.V. resistance of H.M.P.E., and it’s a little bit heavier.

Nylon: Strong yet stretchy nylon is commonly used in applications for which shock absorption is important, such as in dock lines and anchor lines.

P.B.O. (Zylon): Polybenzoxazole is extremely low stretch and high strength. It’s also ungodly expensive and lacks the durability that most cruisers desire. As such, P.B.O. is usually only found on high-end raceboats.

Polyester (Dacron): For decades, polyester has been the go-to rope for cruising-boat halyards and sheets. It’s cost efficient, strong, and resists ultraviolet radiation.

Polypropylene: Usually used in applications like ski and dinghy tow ropes, polypropylene is lightweight and can float. Alone, polypropylene isn’t usually seen in cruising-boat lines since it’s very susceptible to U.V. degradation, but it’s sometimes combined with other fibers that benefit from its lightweight, low-cost qualities.

Extract courtesy Jen Brett and Cruising 

You can read more about running rigging and repairing whilst on passage in my ebook 'Sailing Adventures in Paradise' downloadable from my website http//