SailNet Community

SailNet Community (http://www.sailnet.com/forums/)
-   Seamanship Articles (http://www.sailnet.com/forums/seamanship-articles/)
-   -   Downwind Passagemaking (http://www.sailnet.com/forums/seamanship-articles/19374-downwind-passagemaking.html)

Mark Matthews 10-01-2002 08:00 PM

Downwind Passagemaking
 
<HTML><P><TABLE cellSpacing=0 cellPadding=0 align=right border=0><TBODY><TR><TD width=8></TD><TD vAlign=top align=left width=250><IMG height=317 src="http://www.sailnet.com/images/content/authors/matthews/100202_MM_lead.jpg" width=250><BR><DIV class=captionheader align=left><FONT color=#000000><B>The author steers his vessel westward in the Caribbean, heading downwind for the first time in over 800 miles.</B></FONT></DIV></TD></TR><TR><TD colSpan=2 height=8></TD></TR></TBODY></TABLE>After cruising through the islands in the Eastern Caribbean for several months, we recently turned westward and began heading along the northern coast of Venezuela aboard our 35-foot sloop <EM>Althea</EM>. A thousand miles or so of downwind sailing stretch ahead as we meander our way toward the Panama Canal. The change in our course from southeast to west means a new and welcome point of sail. At least one benefit of our new heading is that spray has stopped flying over the dodger. Yes, we're finally on a downwind run and hope to be so for sometime to come. And with that in mind, I'd like to offer a few thoughts on downwind cruising for passagemakers.</P><P>Sailing downwind presents a paradox of sorts: it is what every sailor hopes for, but the reality of a long down wind run is that it demands attention, more so than most any other point of sail. That's right, the wind and waves and often times favorable currents are finally scooting your vessel along toward its destination, but the wind can bring a false sense of security because when it blows from behind because it is always stronger than it seems. With the boat traveling in the same direction as the wind, the apparent wind is weaker. And you'll probably find that the boat will roll from side to side as you tend to fly more canvas in stronger breezes. The other thing to remember about downwind sailing is that it prompts you to make more frequent trips to the bow.</P><P><STRONG>Safety on Deck</STRONG>&nbsp;&nbsp;&nbsp; Despite the trend aboard contemporary boats for everything to be done from the cockpit, many tasks for downwind sailing cannot be accomplished from the cockpit, like setting up or taking down a whisker pole or spinnaker pole, for example. This means trips forward to adjust the spinnaker pole, whisker pole, to set the foreguy or preventers will be occur more often than on other points of sail. Harnesses and jack lines should be worn when going forward if conditions warrant them—at night or when the wind is blowing over 12 knots are the criteria we use, although risk assessment varies from boat to boat and crew to crew. Regardless, one hand for you, one hand for the boat is still good advice.</P><P><TABLE cellSpacing=0 cellPadding=0 align=right border=0><TBODY><TR><TD width=8></TD><TD vAlign=top align=left width=323><IMG height=228 src="http://www.sailnet.com/images/content/authors/matthews/100202_MM_clutter.jpg" width=323><BR><DIV class=captionheader align=left><FONT color=#000000><B>On board the average cruising vessel there's no shortage of things on deck that can snag a safety harness tether, so caution when going forward from the cockpit is a must.</B></FONT></DIV></TD></TR><TR><TD colSpan=2 height=8></TD></TR></TBODY></TABLE><P>Veteran passagemakers know that there is no shortage of things that can snag a harness tether on deck—sheets, guys, poles, and other cruising gear like dinghies and jerry cans that end up lashed on deck aboard many cruising boats. On board <EM>Althea</EM>, we've made an attempt to keep our decks as uncluttered as possible for this reason, but we still have the mast, sail, and oars for the sailing dinghy, the gas can for the dinghy and two surfboards to contend with as on-deck cargo. The key we find is situational awareness while working on deck. You need to know at all times where the boom is and be aware of other loaded pieces of sail handling gear. A wind shift or an errant move by the helmsman can send the boom hurtling overhead in an accidental jibe that can break expensive sailing gear or do damage to tender crewmembers. With that safety caveat out of the way, when the wind and seas are working in concert to get you to your destination, it's certainly true that you are likely to wear a bigger smile while heading downwind than on any other point of sail. </P><P><STRONG>Mainsail Trim</STRONG>&nbsp;&nbsp;&nbsp; Our new westerly course means setting up the mainsail a bit differently than we did during our previous bash through the eastern Caribbean. The outhaul has gone forward for the first time in a long time, and the halyard tension has been eased to foster a deeper draft and fuller shape in the mainsail. The boom vang is also getting more use now, keeping the boom straight and level to restrain it from lifting and dropping in between the waves.</P><P>With the mainsail now out nearly as far as it will go, the next step is to prevent it from jibing inadvertently. Accidental jibes are caused when the wind shifts behind or the boat changes heading, and the mainsail unexpectedly goes flying overhead. The remedy for this is to rig a preventer. A preventer can be fashioned in a variety of ways. We prefer using a block and tackle rigged to a stout padeye on deck, or clipping a snatch block onto the toe rail to lead a line that's secured to the boom forward and then aft to where it can be made fast near the cockpit. If you execute an accidental jibe with a preventer set, the mainsail simply backwinds, and that should allow the helmsman to recover and adjust the boat's course to bring the wind back on the proper side of the mainsail. The boat will hopefully be carrying enough momentum for a simple quarter turn or so of the wheel to fix the situation and for the sail to fill&nbsp;properly again. </P><P><TABLE cellSpacing=0 cellPadding=0 align=right border=0><TBODY><TR><TD width=8></TD><TD vAlign=top align=left width=323><IMG height=238 src="http://www.sailnet.com/images/content/authors/matthews/100202_MM_preventer.jpg" width=323><BR><DIV class=captionheader align=left><FONT color=#000000><B>The preventer on this vessel originates from the middle of the boom where a two-to-one purchase system leads aft to the winch in the foreground, making it easy to adjust from the cockpit.</B></FONT></DIV></TD></TR><TR><TD colSpan=2 height=8></TD></TR></TBODY></TABLE><P>The best preventer is one that can be adjusted from the cockpit and rigged so that it can be released under load. This usually means having the cockpit end of it cleated on a stout cleat or made fast around a secondary winch. That way should the boat not be able to recover from the back-winded main, instead of an accidental jibe, you'll only experience a controlled one. On <EM>Althea</EM>, our preventer is a three-to-one block and tackle where one end is attached to a bale on the middle of the boom and the other shackled to a stout pad eye on deck just aft of the shrouds. The line is then run aft to a cleat in the cockpit.&nbsp; But keep in mind that preventers aren't just for boisterous conditions. A mainsail that bounces around in light wind and rolly seas will have a shorter life than one that is tamed by a preventer, and using a preventer in conditions like that tends to promote better performance and a happier crew.</P><P><STRONG>Genoa Trim</STRONG>&nbsp;&nbsp; The lighter apparent wind from behind means that we've started flying the larger genoa on a more consistent basis, giving our working jib a well-deserved break. Whereas while we were beating, we took the genoa down in anything over 15 knots it, now we can now fly it in winds ranging from 15 to 20 knots. Life can get interesting fast, however, when the wind increases and the sail that was perfect just a few minutes before becomes something with a mind of its own. Wrestling a powerful sail down is more a matter of technique than brute strength—the sail is stronger than you are, so be smarter than it is. The best way to get a headsail down in big winds is to use the windshadow of the mainsail to blanket the genoa. With the genoa in the lee of the main, its raw power is gone and the task becomes as simple as releasing the halyard and guiding the sail down on deck, or furling the sail if your's is on a roller-furler. </P><P>We find the wing-and-wing technique, with the mainsail out on one side and the genoa poled out on the other to be an effective one for downwind sailing. Rigging the pole on the genoa is much easier if the pole has been properly maintained. Spinnaker pole ends are notoriously susceptible to corrosion and ensuring that the spinnaker pole ends are easy to open and close can make rigging the pole much easier. Once the boat is on course and the main sail is trimmed and a preventer rigged, we then hoist the genoa. The person on the helm steers a course that keeps the genoa flying, while the person on the foredeck—usually me—readies the pole. Although there are a number of sequences that work for this, I usually raise the pole with the uphaul first, attach the outboard end of the pole to the sheet, and then attach the inboard end to the spinnaker ring, taking care to keep a tight hold of the pole once it is connected to the sail, as the forces the sail generates can be significant. </P><P><TABLE cellSpacing=0 cellPadding=0 align=right border=0><TBODY><TR><TD width=8></TD><TD vAlign=top align=left width=250><IMG height=317 src="http://www.sailnet.com/images/content/authors/matthews/100202_MM_whiskerpole.jpg" width=250><BR><DIV class=captionheader align=left><FONT color=#000000><B>The whisker pole aboard this boat is set to keep the headsail projecting as much of its area to the wind as possible, making for more efficient downwind sailing. And using a whisker pole in this fashion allows the helmsman a little more latitude while sailing wing-and-wing.</B></FONT></DIV></TD></TR><TR><TD colSpan=2 height=8></TD></TR></TBODY></TABLE><P>Depending on the conditions, I may or may not also attach a foreguy, to keep the pole from climbing. Our pole is heavy enough that it usually stays level without a foreguy. A number of larger cruising boats have more elaborate twin pole tracks with the pole permanently attached to the track on the mast. This way the inboard end of the pole can slide up the mast, allowing the outboard end of the pole to be easily attached to the genoa sheet. After doing that, the inboard end of the pole can be slid down, keeping the handling of sail loads to a minimum. Another way to set the pole is to blanket the genoa behind the mainsail and then attach the pole to the lazy sheet. Then pull the topping lift up, jibe the genoa, and voila, you're up and running.</P><P>With full so much sail area up while you're heading downwind, it's important to keep an eye on chafe. On long passages the halyards should periodically be adjusted so they don't wear in the same spot. The mainsail can also chafe against the spreaders and aft lower shrouds, and it's important to keep an eye on the pole as it can rub against the forward lower shrouds and become damaged over time. It's also worth keeping in mind that, should you encounter a ship or other converging traffic, changing your course can become something of a scramble when sailing wing and wing. You'll have to adjust the pole and its uphaul and the sheet, and you'll have to adjust the preventer—none of which should be last-minute affair. Changing course early rather than waiting to see how events will unfold is always the best course of action in these situations.</P><P><STRONG>Spinnakers</STRONG>&nbsp;&nbsp;&nbsp; Another valuable aspect of downwind sailing is that it allows you to get more familiar with sails like the spinnaker. Mostly because the spinnaker we have on board <EM>Althea</EM> is old and worn, flying it is usually something of a special occasion. We don't usually get that sail out in anything but the most benign conditions. Still we fly the sail we affectionately call ‘stinky' (due to it being shoved in a lazerette wet one time too many) every chance we can, despite the extra work that's involved. </P><P>To prepare the chute, find the head of the sail and follow each luff tape down to the clew. Stuff the bulk of the sail back in its bag leaving the three corners sticking out and carry the bag forward to attach the appropriate controls. Steve Colgate offers a good, clear description of setting, trimming, and dousing a spinnaker in his article <A class=articlelink href="http://www.sailnet.com/forums/showthread.php?threadid=20665">Spinnaker Fundamentals</A>, so I won't go into that here. But suffice it to say that if the conditions permit, you can truly enhance the downwind performance of your boat by using your spinnaker. Sure, it's easier said than done, but with a bit of practice flying the chute can become a valuable part of your downwind strategy. And it's something else to savor before you have to start heading uphill again.<BR><HR align=center width="75%"><P></P><P clear=all><P><BR><STRONG>Suggested Reading:</STRONG></P><P><STRONG><STRONG><A class=articlelink href="http://www.sailnet.com/forums/showthread.php?threadid=19862">Refining Your Downwind Sails</A></STRONG> by Brian Hancock<BR><BR><A class=articlelink href="http://www.sailnet.com/forums/showthread.php?threadid=20368">Optimizing Your Downwind Performance</A> by John Kretschmer<BR><BR><A class=articlelink href="http://www.sailnet.com/forums/showthread.php?threadid=19794">Using the Asymmetrical Spinnaker</A> by Brian Hancock</STRONG></P><P><STRONG>SailNet Store Section: <A class=articlelink href="http://www.sailnet.com/store/departments.cfm?id=852">Block and Tackle</A><BR></STRONG></P></HTML>


All times are GMT -4. The time now is 01:12 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012