As the name implies, there is usually only one cell with this type of thunderstorm. Also called a “pulse” thunderstorm, the ordinary cell consist of a one time updraft and one time downdraft. In the towering cumulus stage, the rising updraft will suspend growing raindrops until the point where the weight of the water is greater than what can be supported.
At which point, drag of air from the falling drops begins to diminish the updraft and, in turn, allow more raindrops to fall. In effect, the falling rain turns the updraft into a downdraft. With rain falling back into the updraft, the supply of rising moist air is cut-off and the life of the single cell thunderstorm is short. Read more
Three days before I leave for the warm waters of Florida and the Caribbean we get hit with a “polar votex”, really a vortex? So enquiring minds want to know why this happened. So here is the explanation, http://www.cnn.com/2014/01/06/showbiz/polar-vortex-explanation/ . By the way, it was 28 degrees south of Jacksonville this morning.
Welcome to the third installment of “What’s in my sea bag?” We are going to share with you what kind of things we would pack depending on what kind of trip and the location. Up next, Kristen Berry. As many of you know, Kristen and I share one brain, so I am looking forward to finding out what I should take to Key West. So Kristen, What’s in the bag?
January is a funny time of year for me. I get excited to head to points south for J World Annapolis winter programs like Key West Race Week, St. Pete NOOD, and the BVI Alumni Flotilla, but inevitably some “arctic vortex” turns my palm tree paradise into a reptile freezer. Read more
I’ve included this image to help us identify and locate each sail control:
Let’s start from the beginning
Outhaul- The Outhaul is attached to the clew (aft corner) of the mainsail then runs through the boom and comes out of the boom about a third of the way back from the mast.
Function: The Outhaul affects the depth of the sail (draft). When tightened it flattens the bottom third of the sail and makes the boat easier to handle in building breeze.
Backstay- The Backstay is connected to the top of the mast and runs back to the stern of the vessel. A line runs along the backstay which tensions the backstay.
Function: When the Backstay is tensioned the mast bows forward and flattens the middle and top of the sail. This causes a dramatic reduction in draft which de-powers the boat and makes it easier to steer and control the boat in a fresh breeze.
Cunningham- The Cunningham is attached just above the tack (forward corner) of the mainsail. It generally runs down to a block attached to the mast just above the deck.
Function: The Cunningham can be used to get more luff (leading edge of sail) tension; used in conjunction with the Outhaul and Backstay is moves the draft forward and completes the depowering of the mainsail.
Halyard- The Halyard is attached to the head (top) of the sail and is used to raise sails to the top of the mast.
Function: The Halyard affects luff tension and draft position. A loose halyard will create a sail with more draft which is great for a light breeze. As the breeze builds a tighter halyard will give you more luff tension and help give a flatter sail shape (when used in conjunction with the “OBC”s it helps alleviate weather helm).
Sheets- Specifically the Mainsheet is attached to the boom and changes the angle the sail has to the wind (angle of attack).
Function: By changing the angle of attack the speed of the boat can be affected. When the sheets are properly trimmed, the boat is at its greatest efficiency. If we over trim or ease the sails the efficiency will rapidly decrease. Easing the sails upwind, will cause the sails to luff and slow the boat down. Over trimming the sails downwind will stall flow and cause the boat to slow down.
Traveler- The traveler is generally located towards the stern in the cockpit relatively close to the driver position. The mainsheet block is connected to the travel car which travels from one side of the boat to the other.
Function: The Traveler changes the sheeting angle of the Mainsheet. The Traveler is primarily used when going upwind. It is used to bring the boom to center-line on a close haul. It can also be used to depower the boat in a heavy breeze. When feeling over powered the traveler can be “dropped” to the leeward side of the boat to create a luff bubble on the leading edge of the mainsail and effectively reduce its sail area by as much as 25%.
Boom-Vang- The Boom-Vang is connected the boom and runs down to the base of the mast.
Function- The Boom-Vang is primarily used downwind to control leech (trailing edge of sail) tension. It also prevents to boom from rising up into air. If it’s windy and turning downwind is difficult, easing the Boom-Vang before heading down will make it much easier. Just remember to put a little tension back on the Boom-Vang once you’ve turned down to the desired course.
When it’s windy and controlling the boat is becoming difficult just remember your OBC’s: Outhaul, Backstay, Cunningham. J World Annapolis Head Coach, Dave Manhiemmer, uses the simple phrase: “The windier it blows the tighter it goes” to help you remember what to do with your OBC’s when it gets breezy.
There is an abundance of books and articles out there written about the single topic of sail trim. It occupies every sailors mind at some point – regardless of whether you identify yourself as a racer, cruiser, daysailor or simply just a sailor.
KB: Koralina, sail trim is a fairly broad topic. In your opinion, what is the most basic way to understand sail trim?
KP: “I often asked myself “how can I ever master such a complex skill?” Every time I go sailing I learn a little more about sail trim which leads me to believe mastery is over-rated, and learning is continuous. None-the-less I have learned a plethora of tips, tricks, and acronyms, over the years, to keep it all straight.
The most common phrase related to sail trim is simply:
“When in doubt, let it out”
In my experience it’s a great place to start; however I’ve altered this long time saying to read “When in doubt, let it out- If it’s luffing, it must come in”
KB: I love that phrase and use the same one. It works from Opti’s to ocean cruisers. When I teach the same concept I say “when in doubt let it out. If you are often in doubt you are rarely in error.” But “letting it out” is a pretty gross trim concept, how can you use it to refine trim?
KP: “It’s easier to explain and understand if we break it down into two parts:
Main trim: “When in doubt, let it out- If it’s luffing, it must come in” works excellent here. As we get more advanced we learn that when we go up wind keeping the boom running along the center line of the boat will give us the greatest amount of lift towards the wind. As we head down off the wind we want to keep easing the sail to the brink of luffing as we turn. You can make sure you have the appropriate trim by easing your mainsheet and few inches and seeing if your sail luffs. If it does then pull it back in and you know you have the right trim. If it does not luff then you know it’s over trimmed and needs to be eased out some more. Generally speaking at the run/broad reach angle we want the sail just off the shrouds. This technique will prolong the life of your sail by not creating a “wear spot”.
Jib trim: “Outside tell-tale, let it out- Inside tell-tale, pull it in” The basic idea here is you want to trim or ease the sail to the “tattling tell-tale”. If you are thinking “Huh?” Let me explain: If you’re sailing on the port tack (wind is coming over your port side, the sails are on the starboard side) the outside tell-tale is the one on the starboard side of the sail, closer to the outside of the boat. The inside tell-tale is the one on the port side of the sail, more inboard. The term tattling refers to the tell-tales tendency to wiggle, or sway uncontrollably.
So if your sailing along on the outside tell-tale is tattling you would want ease the sail out toward that outside tell-tale. Thus I like the saying: “Outside tell-tale, let it out- Inside tell-tale, pull it in”
KB: Are there any good tricks for remembering proper jib trim?
KP: “Yes! Using the tell-tales is the easiest way to get perfect jib trim every time. The tell-tales are your “tell tale” symbols on your jib to help you refine its trim when sailing on a beam reach or above. Usually they are pieces of yarn colored red and green on either side of your jib (but not always I’ve seen blue instead of green).
So you’ve picked your direction and set your sails (using the tips above to help) and now you want to sit back and drive your boat to that trim. This is often what we do when we are sailing close-hauled or just out for fun with friends. It’s easy and only takes small adjustment of your wheel or tiller to keep your boat cruising forward.
Tiller driven boats: “Tiller towards the tattling tell-tale” This means if your starboard tell-tale is wiggling around push/pull your tiller to starboard side until that tell-tale settles down and streams aft (towards the back of your boat).
Wheel Steered Boats: “Turn away from trouble.” This means if you starboard tell-tale is wiggling around you want to steer to port. Be careful though, if you steer too far you will cause your port telltale to wiggle.
KB: These are some great tips to get us thinking about sail trim. If someone was interested in learning more what would you tell them?
KP: “I really hope you found this helpful. At J World we fully endorse a life of learning, amongst our staff and our students. So, if you have any questions feel free to comment below. We would be happy to explain anything further. We also cover this material in 1hr, 3hr, and full day formats under the title of “Sail Trim and Balance”. Just e-mail us for more information on the full length version.”
Every spring thousands of sailor pull the covers off their boats, rig the lines and hoist their sails for the first time. Even the most seasoned sailors should consider taking a few minutes to review their fundamentals, safety gear and standard
procedures to ensure the season starts off right. Over the next few weeks we will be looking at a series of topics designed to get you refreshed and ready to sail.
If you sail in a busy area, like Baltimore’s Inner Harbor or the mouth of the Severn River in Annapolis, knowing the rules of the road will arm you with the knowledge to safely navigate what can be a daunting maze of zipping powerboats, tacking sailboats and working boats like tugs and taxis.
I recently had a conversation with veteran J World Annapolis Coach and Chesapeake Boating Club Baltimore staffer Koralina Pior, and asked her to tell me a little about how she teaches (and remembers herself) the rules of the road. Below is an excerpt from that conversation.
KB: The rules of the road can seem daunting to even seasoned sailors. What are the basics that people need to know before they hit the water?
KP: “Before we get started lets briefly define some helpful terms-
Stand-on vessel: The stand on vessel is the boat that has right-of-way. The Stand-on vessel is required to maintain course and speed.
Give-way vessel: The give-way vessel is the boat that must keep clear of the stand-on vessel. The Give-way vessel is required to make a clear and obvious change in course to alert the stand-on vessel of their intentions.”
KB: The definitions are helpful, but is there any sort of pecking order to who has right of way when two boats come together head to head, in crossing or overtaking situations?
KP: “In fact there is! Remembering the pecking order is important, because it will quickly answer the first question about who is the stand-on and who is the give-way vessel. Simply put (and worth memorizing), the hierarchy of right-of-way is:
Vessels not under command
Vessels restricted in their ability to maneuver
Vessels constrained by draft
Fishing vessels engaged in fishing, with gear deployed
Power driven vessels
Each of these terms is defined in the International Regulations for Preventing Collisions at Sea. For instance a “fishing vessel”, is defined any vessel fishing with nets, lines, trawls, or other fishing apparatus which restrict maneuverability, but does not include a vessel fishing with trolling lines or other fishing apparatus which do not restrict manageability. So the guy in the runabout with the planer boards is a power driven vessel and not a vessel engaged in fishing.”
KB: OK, so the “pecking order” makes sense, and clarifies that sailboats have “right of way over powerboats” how can you easily remember who is the “stand on vessel” and who is the “give-way vessel?” when two boats meet?
KP: “Right – sail over power is the most common right of way scenario. Of course if you are a sailboat but you are using the motor – you are actually a powerboat. AND if you are a sailboat that is overtaking a powerboat, you have to give-way to the powerboat. Between sailboats, there is an additional pecking order. One of the best ways to remember your Right-of-way rules between sailboats is to remember this simple acronym
S = Starboard over Port: A boat on a starboard tack is the stand-on vessel. Thus a boat on a port tack must give-way to the starboard tack boat.
L = Leeward over Windward: If two boats are sailing on the same tack the boat that is more leeward is the stand-on vessel. Thus the boat that is more windward must give-way to the leeward most vessel.
O = Overtaken over Overtaking: This rule applies to boat sail boats and power boats. If a boat is approaching another boat from clear astern and is moving faster than the boat ahead, that boat is the give-way vessel. The boat which is being overtaken is the stand-on vessel. Please note even if a power boat is the boat clear ahead, it is the responsibility of the sailboat to give-way.
When I teach rules of the road, I also like to add a “W” to the acronym. In my teaching system “W” stands for “Working.” In many cases a sailboat would technically have right of way over a powerboat (for instance when a sailboat and a water taxi are in a crossing situation) but sometimes it pays to defer the right of way. Some consider this an act of deference and some consider this operating under the “rule of gross tonnage.”
W = Working over leisure: A commercial boat that is working (e.g.: crabbing boat, military, tanker)is considered the stand-on vessel. The boat which is sailing for leisure is the give-way vessel. Please note this rule also applies to both sailboats and power boats.”
KB: Koralina, this is great information. Are there other resources people might use to learn more about the rules of the road?
KP: “Right-of-way rules are important to every sailor to insure everyone’s safety on the water. To learn more about right-of-way rules you can visit the Boat US website at: http://www.boatus.com/foundation/guide/navigation_1.html and of course we cover right of way rules along with dozens of other topics in our sailing fundamentals and basic keelboat courses.”