(mostly summarized from "The Voyager's Handbook" by Beth Leonard)
- Need light-air sails.
- May want slightly heavier spinnaker than usual, to keep its shape better.
- Adjust sails occasionally to change chafe points.
- Minimize chafe due to rolling (all-headsail rig may be best).
- Want good helm balance to ease auto-steering (all-headsail rig may be best).
- Prevent jibes (all-headsail rig may be best).
SailNet - John Rousmaniere's "Deadly Serious about Booms"
From John Dunsmoor:
> (While dealing with a broken gooseneck and loose boom
> and flailing mainsail,) I kept reminding
> myself not to get myself in a position to be injured.
> I didn't want to get tangled in a line or hit by the
> boom and get an arm broken or get thrown overboard.
This is so important and can not be over-emphasized. While teaching, every once in a while, I would have a student I would refer to as a Leaper. They had the tendency to jump first and think later. I would make them wear a safety harness; this meant that they would have to THINK about what they were doing, and unhook the harness, and find another place to hook it, BEFORE leaping to some task. ...
Keeping in mind risk management, especially in an emergency, including where the boat is pointing and the hazards to navigation is a very good idea. One point to always remember, the way you came in, is a safe way to get out. More than once I have turned a vessel around and retraced my route, for no other reason than to give us some time. More than once I stayed at the wheel just maintaining position while my navigator triple-checked our position. Another point is when it does not look right, or feel right, STOP. So many sailors get into real trouble and when you asked them about the crash, they remarked that things just didn't look right, or they had that feeling that there was something wrong and ignored it.
Keeping your wits and managing risk is even more important when you go bluewater, and there is NO help within three days to a week. You get hurt, you could very well die. Something as simple as a toothache could kill you.
...
Gary was sailing his 34 Tartan down island with a bunch of friends and ran up to the foredeck for something, they can not even remember what, slipped and hit his head on the windlass, opened up his brain, coma, damn near killed him. Took a year to get over. Another guy we met had sailed across the Atlantic alone, Frenchman, stood up on his aftdeck and got whacked by a blade of a windbugger, he died. I teach the anatomy of an accident, and life commonly goes from OK to sh*t without much warning. I think the key is luck and serious focus. It seems that if you are paying attention, just as focused on the how, as you are on the what, the gremlins have less of a chance to sneak up on you. Most everyone gets focused on the what, the task. And they get whacked on the way, because the way was never really a focus. The victum was focused on the destination and not the journey.
> and flailing mainsail,) I kept reminding
> myself not to get myself in a position to be injured.
> I didn't want to get tangled in a line or hit by the
> boom and get an arm broken or get thrown overboard.
This is so important and can not be over-emphasized. While teaching, every once in a while, I would have a student I would refer to as a Leaper. They had the tendency to jump first and think later. I would make them wear a safety harness; this meant that they would have to THINK about what they were doing, and unhook the harness, and find another place to hook it, BEFORE leaping to some task. ...
Keeping in mind risk management, especially in an emergency, including where the boat is pointing and the hazards to navigation is a very good idea. One point to always remember, the way you came in, is a safe way to get out. More than once I have turned a vessel around and retraced my route, for no other reason than to give us some time. More than once I stayed at the wheel just maintaining position while my navigator triple-checked our position. Another point is when it does not look right, or feel right, STOP. So many sailors get into real trouble and when you asked them about the crash, they remarked that things just didn't look right, or they had that feeling that there was something wrong and ignored it.
Keeping your wits and managing risk is even more important when you go bluewater, and there is NO help within three days to a week. You get hurt, you could very well die. Something as simple as a toothache could kill you.
...
Gary was sailing his 34 Tartan down island with a bunch of friends and ran up to the foredeck for something, they can not even remember what, slipped and hit his head on the windlass, opened up his brain, coma, damn near killed him. Took a year to get over. Another guy we met had sailed across the Atlantic alone, Frenchman, stood up on his aftdeck and got whacked by a blade of a windbugger, he died. I teach the anatomy of an accident, and life commonly goes from OK to sh*t without much warning. I think the key is luck and serious focus. It seems that if you are paying attention, just as focused on the how, as you are on the what, the gremlins have less of a chance to sneak up on you. Most everyone gets focused on the what, the task. And they get whacked on the way, because the way was never really a focus. The victum was focused on the destination and not the journey.
Freighters: SailNet - Randy Harman's "Encounters of the Large Kind"
Light-air sailing:
Sailing more and motoring less:
From letter from Bev and Dave Feiges in
8/2001 issue of Seven Seas Cruising Association bulletin:
- Roller-furling on all sails, and all controlled from cockpit.
- Jib whisker pole for sailing downwind. Best to have a pole always
attached to track on mast, and controlled via lines, instead of
an unattached one stored on deck somewhere.
- Spinnaker or gennaker, and mizzen staysail, for light-wind sailing.
- Feathering propeller, for keeping speed up in light winds.
- Take advantage of winds when you get them; you may have to sacrifice other plans.
- Wind-vane self-steering or an auto-pilot ? Sometimes you can balance the sails and steer a constant course, but this often fails if there is a swell. Self-steering frees you from the helm.
Reducing motion while sailing:
Mostly from article by Steve Dashew in 8/2001 issue of Cruising World magazine:
- Try increasing or reducing amount of sail.
- Try adjusting point of sail. Longer track to destination may be more comfortable.
- Start or stop motor-sailing.
- If motor-sailing, try changing engine speed.
- Stop sailing and wait a day for better conditions.
- Change distance from land (may change depth of water, direction of wind or swell, shield from wind or swell, get out of or into current).
Motor-sailing:
Keep sails up to:
- Dampen rolling/pitching.
- Increase speed if reaching.
- Be ready to sail if wind picks up.
- Engine water intake could come above waterline.
- Engine oil may not circulate properly.
- Fuel tank pickup may not be able to reach fuel.
Sailing a ketch:
(summarized from "The Voyager's Handbook" by Beth Leonard)
- Reefing: reef/drop mainsail first.
- Windward: drop mizzen completely.
- Heaving-to: drop headsail and mainsail, use mizzen only.
Pardey's generally agree.
But John Rousmaniere disagrees, says drop mizzen and use storm jib and trysail. - Broad reach: use jib/genoa and mizzen.
- Mizzen should be 1/3 to 1/2 size of mainsail; many are too small.
Anchoring:
If wind-shifts make the anchor rode snag on coral heads,
adding a few floats on the near part of the rode will keep it from snagging there.
From Stuart Burgess:
From Stuart Burgess:
Inevitably wind and swell will be from different directions and the
boat will roll like a pig which is very wearing. Get a 60+ foot length of nylon
rode and splice a chain hook on the end. Hook the chain hook onto your
anchor chain once anchored and then let out another 20-30 feet and then take
the free end outside your rigging and on to an aft winch. You can then pull
the stern around on the winch so that the bow is facing into the swell.
SailNet - Mark Matthews' "The Particulars of Rafting Up"
Docking:
Paraphrased from bernie on Cruising World message board:
To avoid blowing sideways out of a slip that
is mostly pilings, wet and tightly tie a couple of lengths
of 1-inch thick 3-strand nylon between pilings
slightly below deck level
to make "solid sides" to the slip.
Canal/Waterway Techniques:
SailNet - Michelle Potter's "Negotiating Bridges"
From David Guenther:
From David Guenther:
Bridges --
Fixed bridges -- When planning a trip I identify the location and get the vertical clearance of fixed bridges on my route. If any are lower than the height of my mast above waterline, I look for alternative routes. If there are none (or none are acceptable), I figure out where I am going to unstep my mast. The spars are then secured above deck on crutches/supports I have made for this purpose which keep it high on the centerline (but low enough to fit under the lowest fixed bridge along the route). This keeps my deck clear for working (locking, docking, and anchoring), keeps the helm clear for steering, provides maximum visibility, permits convenient access below, allows hatches to be opened for ventilation or emergencies, and permits dinghy to be stored on deck. It also serves as a ridge support for a tarp over the cockpit for protection from sun and rain. Assuming a masthead mounted VHF antenna, alternative arrangements for VHF communication are necessary. A handheld unit is fine for communication, but may not be adequate for receiving broadcasts on marine weather channels.
Swinging bridges and drawbridges -- Some open on demand; others open on a particular schedule (typically on the hour or half-hour). I find out which are which and get the schedules of those that operate on a schedule. I also find out the VHF channel monitored by and the sound signals used to communicate with the bridge attendants. I try to time my arrival to correspond with bridge opening schedules, preferring to be a bit early rather than late. Because some waiting is usually inevitable (sometimes a lot of waiting if I arrive just after closing), I plan for that.
Locks --
When approaching a lock, you may have to wait. Some locks have traffic lights -- green = open, red = closed. If you need to wait, there may be a wall or dock to tie to. If the waiting area is full or there is none, it is necessary to stand off. There is often at a slight current pulling you toward or away from the lock, so some manuevering under power will be necessary to hold your position. Do not approach the lock too closely -- there may be turbulence when it opens. You also want to make sure your position does not interfere with boats exiting the lock.
When the lock is opened, the lock attendants will direct the waiting boats to specific locations. First there does not necessarily mean first in. In small locks (like those in the Trent-Severn Waterway), boats are put on both sides. Since you may be directed to either the port or starboard side of the lock, you need to have fenders and bow and stern lines ready for either possibility. Sometimes boats are rafted, which requires breast and spring lines as well. Check to make sure nothing is protruding beyond the gunwales that could hit the walls.
Equipment needs -- Adequate size and number of fenders. I use four 10"-12" fenders per side on my 26 footer. I have not done the Welland Canal yet, but have been told burlap bags filled with straw are the recommended fenders and can be purchased from marinas at either end of the canal. Having a way to quickly adjust the location of the fenders (horizontally and vertically) is a big help. Four transit lines -- two bow and two stern. Length and diameter will depend upon lock. Boat hooks -- one secured but easily accessible on bow and another at the stern. Work gloves -- cotton or leather.
Crew/linehandlers -- I have singlehanded my 26 footer through small locks, but do not recommend it, especially when up locking. For most small locks, two people (helmsperson plus one linehandler) are adequate when down locking. The line handler handles the bow line, the helmsperson handles the stern line. Holding the boat against the turbulence encountered when up locking (especially when the boat is located at the front of the lock where the turbulence is greatest) may require more than two people. Lockmasters can deny entrance if they don't believe the boat can be handled properly. Some locks require a minimum number of people on board. If you don't have the required number, it is usually easy to hire someone or borrow crew from another boat. Some canals also require transiting vessels to take an advisor/pilot on board.
Locking technique and precautions -- Specifics will vary. In small locks, you enter the lock slowly and come to a stop parallel to the wall. In hydraulic lift locks, you then just tie to cleats, bollards, or other points on the wall. The boat is essentially in a "bathtub" and the whole tub moves up and down, so the water level does not change relative to the boat.
Some locks have attachment points that move up and down with water level or "drop lines" (vertical lines spaced along the lock wall; the ends are permanently attached at the top and bottom of the wall). One end of the bow and stern transit lines is cleated off to a deck cleat. The transit line is looped around the attachment point/drop line and the free end is held in your hand or, if necessary to maintain control, given it a turn around a cleat (a figure eight works well) or winch. But do not cleat it off. The loop in the transit line is supposed to slide up or down the drop line as the water level changes. You may have to loosen, lengthen, or shorten the line quickly to keep the boat in the proper position. Worst case scenerio, the loop binds and the boat will either be pulled under or left hanging.
In some small locks, one end of each transit line is attached to a bollard at the top of the lock wall. The free end is run through a chock, fairlead, or cleat on the bow and stern of the boat and line is let out or hauled in as the water level changes. Again, it may be necessary to take a turn around a cleat or winch to handle the loads, but never cleat off.
On big locks, you want a center tie when up locking.
Precautions -- It is important to keep the boat properly positioned and under control at all times. Turbulence when uplocking, especially at the front of the lock, can really try to toss the boat around. You want to avoid slack in the transit lines which will put high shock loads on cleats, etc. or allow the boat to slam into the lock wall. Be sure never to let hands or other body parts get between the boat and the lock wall. The use of a boat hook is recommended to grab drop lines/attachment points, pull in, or fend off. However, when things are going well, I have used my hands for this. Gloves are nice because walls and some lines are slimey and may be rough. They can also help and protect your hands when handling transit lines.
After the lock has completed filling/emptying, the lock attendants will direct the order of exit. Don't be in too much of a hurry to exit. There is usually a slight surge when the gates are opened.
Payment of fees -- You usually pay before entering the first lock. On some small locks, you can pay on a per lock basis while you are locking through.
VHF communication -- Know the VHF channel monitored by the lockmasters so you can contact them if necessary.
Hours of operation -- When transiting a series of locks on a waterway, the lockmasters keep in touch with each other by telephone to organize the flow of boats. If it is near closing time, telling a lockmaster you are or are not heading for the next lock helps them. On the Trent-Severn and Erie, you can tie up at the locks to spend the night -- but may have to wait to tie up until after the locks close and may have to untie before they open.
Dinghy -- Stow it on board. Some locks will treat a towed dinghy as a separate boat and charge a fee for it. But mainly, it is a real pain to maneuver in a lock with a dinghy on a tow line off the stern.
Miscellaneous --
Aids to navigation -- Aids to navigation may be unique for the waterway so you need to learn them. Some waterways have summits and the buoyage will reverse on the other side of the summit. For example, on the Trent-Severn, red buoys are on your starboard going upstream. Once you cross the summit, you are heading downstream and the red buoys are on the port side.
Rules of the road -- Vessels travelling downstream have right of way. This is important when travelling through a narrow or fast flowing section of waterway since vessels travelling downstream have less steerage control.
Water depths can vary and may be shallow, so knowing your actual draft is important.
When entering areas with limited maneuverability or blind spots, I broadcast a securite warning to let other boats know I am coming.
Anchoring -- make sure you are out of the channel and use an anchor light.
Speed limits -- Sailboats probably won't have to worry about exceeding speed limits. But in sections without speed limits, you are likely to encounter powerboat wakes. Be careful they don't push you into an awkward or dangerous situation.
Fixed bridges -- When planning a trip I identify the location and get the vertical clearance of fixed bridges on my route. If any are lower than the height of my mast above waterline, I look for alternative routes. If there are none (or none are acceptable), I figure out where I am going to unstep my mast. The spars are then secured above deck on crutches/supports I have made for this purpose which keep it high on the centerline (but low enough to fit under the lowest fixed bridge along the route). This keeps my deck clear for working (locking, docking, and anchoring), keeps the helm clear for steering, provides maximum visibility, permits convenient access below, allows hatches to be opened for ventilation or emergencies, and permits dinghy to be stored on deck. It also serves as a ridge support for a tarp over the cockpit for protection from sun and rain. Assuming a masthead mounted VHF antenna, alternative arrangements for VHF communication are necessary. A handheld unit is fine for communication, but may not be adequate for receiving broadcasts on marine weather channels.
Swinging bridges and drawbridges -- Some open on demand; others open on a particular schedule (typically on the hour or half-hour). I find out which are which and get the schedules of those that operate on a schedule. I also find out the VHF channel monitored by and the sound signals used to communicate with the bridge attendants. I try to time my arrival to correspond with bridge opening schedules, preferring to be a bit early rather than late. Because some waiting is usually inevitable (sometimes a lot of waiting if I arrive just after closing), I plan for that.
Locks --
When approaching a lock, you may have to wait. Some locks have traffic lights -- green = open, red = closed. If you need to wait, there may be a wall or dock to tie to. If the waiting area is full or there is none, it is necessary to stand off. There is often at a slight current pulling you toward or away from the lock, so some manuevering under power will be necessary to hold your position. Do not approach the lock too closely -- there may be turbulence when it opens. You also want to make sure your position does not interfere with boats exiting the lock.
When the lock is opened, the lock attendants will direct the waiting boats to specific locations. First there does not necessarily mean first in. In small locks (like those in the Trent-Severn Waterway), boats are put on both sides. Since you may be directed to either the port or starboard side of the lock, you need to have fenders and bow and stern lines ready for either possibility. Sometimes boats are rafted, which requires breast and spring lines as well. Check to make sure nothing is protruding beyond the gunwales that could hit the walls.
Equipment needs -- Adequate size and number of fenders. I use four 10"-12" fenders per side on my 26 footer. I have not done the Welland Canal yet, but have been told burlap bags filled with straw are the recommended fenders and can be purchased from marinas at either end of the canal. Having a way to quickly adjust the location of the fenders (horizontally and vertically) is a big help. Four transit lines -- two bow and two stern. Length and diameter will depend upon lock. Boat hooks -- one secured but easily accessible on bow and another at the stern. Work gloves -- cotton or leather.
Crew/linehandlers -- I have singlehanded my 26 footer through small locks, but do not recommend it, especially when up locking. For most small locks, two people (helmsperson plus one linehandler) are adequate when down locking. The line handler handles the bow line, the helmsperson handles the stern line. Holding the boat against the turbulence encountered when up locking (especially when the boat is located at the front of the lock where the turbulence is greatest) may require more than two people. Lockmasters can deny entrance if they don't believe the boat can be handled properly. Some locks require a minimum number of people on board. If you don't have the required number, it is usually easy to hire someone or borrow crew from another boat. Some canals also require transiting vessels to take an advisor/pilot on board.
Locking technique and precautions -- Specifics will vary. In small locks, you enter the lock slowly and come to a stop parallel to the wall. In hydraulic lift locks, you then just tie to cleats, bollards, or other points on the wall. The boat is essentially in a "bathtub" and the whole tub moves up and down, so the water level does not change relative to the boat.
Some locks have attachment points that move up and down with water level or "drop lines" (vertical lines spaced along the lock wall; the ends are permanently attached at the top and bottom of the wall). One end of the bow and stern transit lines is cleated off to a deck cleat. The transit line is looped around the attachment point/drop line and the free end is held in your hand or, if necessary to maintain control, given it a turn around a cleat (a figure eight works well) or winch. But do not cleat it off. The loop in the transit line is supposed to slide up or down the drop line as the water level changes. You may have to loosen, lengthen, or shorten the line quickly to keep the boat in the proper position. Worst case scenerio, the loop binds and the boat will either be pulled under or left hanging.
In some small locks, one end of each transit line is attached to a bollard at the top of the lock wall. The free end is run through a chock, fairlead, or cleat on the bow and stern of the boat and line is let out or hauled in as the water level changes. Again, it may be necessary to take a turn around a cleat or winch to handle the loads, but never cleat off.
On big locks, you want a center tie when up locking.
Precautions -- It is important to keep the boat properly positioned and under control at all times. Turbulence when uplocking, especially at the front of the lock, can really try to toss the boat around. You want to avoid slack in the transit lines which will put high shock loads on cleats, etc. or allow the boat to slam into the lock wall. Be sure never to let hands or other body parts get between the boat and the lock wall. The use of a boat hook is recommended to grab drop lines/attachment points, pull in, or fend off. However, when things are going well, I have used my hands for this. Gloves are nice because walls and some lines are slimey and may be rough. They can also help and protect your hands when handling transit lines.
After the lock has completed filling/emptying, the lock attendants will direct the order of exit. Don't be in too much of a hurry to exit. There is usually a slight surge when the gates are opened.
Payment of fees -- You usually pay before entering the first lock. On some small locks, you can pay on a per lock basis while you are locking through.
VHF communication -- Know the VHF channel monitored by the lockmasters so you can contact them if necessary.
Hours of operation -- When transiting a series of locks on a waterway, the lockmasters keep in touch with each other by telephone to organize the flow of boats. If it is near closing time, telling a lockmaster you are or are not heading for the next lock helps them. On the Trent-Severn and Erie, you can tie up at the locks to spend the night -- but may have to wait to tie up until after the locks close and may have to untie before they open.
Dinghy -- Stow it on board. Some locks will treat a towed dinghy as a separate boat and charge a fee for it. But mainly, it is a real pain to maneuver in a lock with a dinghy on a tow line off the stern.
Miscellaneous --
Aids to navigation -- Aids to navigation may be unique for the waterway so you need to learn them. Some waterways have summits and the buoyage will reverse on the other side of the summit. For example, on the Trent-Severn, red buoys are on your starboard going upstream. Once you cross the summit, you are heading downstream and the red buoys are on the port side.
Rules of the road -- Vessels travelling downstream have right of way. This is important when travelling through a narrow or fast flowing section of waterway since vessels travelling downstream have less steerage control.
Water depths can vary and may be shallow, so knowing your actual draft is important.
When entering areas with limited maneuverability or blind spots, I broadcast a securite warning to let other boats know I am coming.
Anchoring -- make sure you are out of the channel and use an anchor light.
Speed limits -- Sailboats probably won't have to worry about exceeding speed limits. But in sections without speed limits, you are likely to encounter powerboat wakes. Be careful they don't push you into an awkward or dangerous situation.
Weather:
Mostly from "Piloting" by Charles Chapman:
From article by Gregg Nestor in 11/2003 issue of Latitudes and Attitudes magazine:
From "Weather Predicting Simplified" by Michael Carr:
Front: the boundary between two different air masses.
The masses probably have different temperatures, moisture contents,
barometric pressures, wind directions and speeds.
Isobars: lines of equal barometric pressure. These reveal high and low pressure centers. Closely spaced lines mean high winds. Wind direction is not necessarily straight from higher to lower pressure; direction is affected by earth's rotation, topography, etc.
High-pressure center: usually means good weather, stable air, light winds.
Low-pressure center: usually means bad weather, strong winds.
Large-scale storms:
Clouds:
Basic forms:
Isobars: lines of equal barometric pressure. These reveal high and low pressure centers. Closely spaced lines mean high winds. Wind direction is not necessarily straight from higher to lower pressure; direction is affected by earth's rotation, topography, etc.
High-pressure center: usually means good weather, stable air, light winds.
Low-pressure center: usually means bad weather, strong winds.
Large-scale storms:
- Cyclone is traveling system of winds rotating counterclockwise (in northern hemisphere) around a low-pressure center and containing a warm front and a cold front.
- Hurricane is traveling system of 70+ knot winds rotating counterclockwise (in northern hemisphere) around a low-pressure center.
- Shower: from large cumulus or small cumulonimbus clouds separated by blue sky.
- Thunderstorm: short duration, from cumulonimbus cloud, thunder and lightning, abrupt fluctuations of temperature, pressure and wind.
- Squall line: row of thunderstorms stretching 100 miles or more.
Clouds:
Basic forms:
- Cirrus (streak):
- Stratus (sheet): slow widespread ascent of stable air.
- Cumulus (heap): unstable air with localized strong updrafts.
- none: low-level cloud.
- Alto: mid-level cloud.
- Cirro: mid-level cloud.
- Nimbus: black rain cloud.
From article by Gregg Nestor in 11/2003 issue of Latitudes and Attitudes magazine:
General predictions from clouds:
- Cumulus (clumpy): if builds quickly and is taller than it is wide, signals instability (squalls, may become cumulonimbus).
- Stratocumulus (cumulus forced to spread out): stable, high-pressure area.
- Stratus (low gray layer): lots of rain.
- Altostratus (mid-level gray layer): indicates moderate deterioration of conditions.
- Altocumulus (mid-level small clumps): fair weather or light rain.
- Cirrus (high-level wispy): leading edge of a front, maybe 24-48 hours ahead of rain.
- Cirrostratus (high-level even layer): darkening indicates front coming.
- Cirrocumulus (high-level scaley): front coming; rain in 12-18 hours.
- Contrails from airplanes: if long-lasting, moisture at high altitudes and front coming.
From "Weather Predicting Simplified" by Michael Carr:
-
High-pressure areas exist where air descending from the upper atmosphere
meets the Earth's surface and moves outward. High-pressure systems
can bring warm or cold temperatures, depending upon where they form. But they always bring
clear weather because of their low humidity, which minimizes cloud formation.
High-pressure systems are viewed warily by sailors, since they often bring light winds or calms. There is, however, a band of dependable winds near a high's perimeter. ... in the Northern Hemisphere, high-pressure systems rotate clockwise ... -
Land and water handle heat input very differently: water absorbs heat with little change in temperature,
whereas land temperature increases noticeably and quickly. When land is heated, its temperature goes up and
it radiates heat back out to the air above. This causes the air above to rise. As air rises, additional
air is drawn in to fill the void; this process creates a thermal trough. Sea breezes, which
develop along beaches each day during the summer, are an example of thermal troughs: air rises
above the land, and cooler ocean air moves landward to fill the void.
-
Upper-air weather charts show the strength and direction of upper-air winds, which influence the
development and movement of surface troughs, ridges, lows and highs. ...
Each wave, or undulation, within the jet stream either moves cold air south or warm air north, causing mixing of air masses and formation of fronts. ...
... the base of the jet stream is at 500 mb ... the 500-mb level is approximately halfway through the atmosphere, giving it a midlatitude elevation of roughly 18,000 to 20,000 feet. ...
Winds at the 500-mb level, and generally throughout the jet stream, blow from west to east. ...
... as upper-level winds move from west to east as ribbons of air, they also undulate in a north-south wave pattern. Dips [south] are called troughs, and rises [north] are called ridges ... in the Northern Hemisphere troughs flow with counterclockwise tendencies and ridges with clockwise tendencies. The direction of flow is important because on the Earth's surface low-pressure systems (depressions, gales, storms) form under upper-level troughs, and high-pressure systems form under upper-level ridges. In the Northern Hemisphere, the counterclockwise motion of upper-level troughs reinforces the counterclockwise tendency of surface lows. ... troughs, whether located at upper levels or on the surface, are generally areas of instability and counterclockwise wind rotation (in the Northern Hemisphere). ...
Hurricanes are very powerful and dangerous low-pressure tropical systems. ... A hurricane begins to form when an upper-level trough forms a westward-traveling wave in the ITCZ. ...
Hurricanes need several ingredients to form:- A tropical wave ... an atmospheric wave of low pressure ...
- Seawater temperatures of 79F or more.
- Surface winds flowing in the same direction as the tropical wave and at a similar speed.
[So a hurricane forms when an upper-level trough (spinning counterclockwise) and surface low (also spinning counterclockwise) hook up and form a closed circulation, using thermal energy from the sea-surface and drawing moisture up from the sea-surface.]
While at anchor for multiple days, keep monitoring weather conditions and forecasts. They may require changing anchorage or position, and you don't want to wait until conditions have become dangerous.
Storm Conditions:
- Heaving-to: want boat to slip sideways downwind, which creates
turbulence in the water upwind of it, smoothing down the
waves and keeping them from breaking.
- Sea anchor: can make one by lashing a board across the flukes of your primary anchor, and letting it out.
See my Sailing a Boat SingleHanded page