Safety on board: preventer setup on Totem

downwind offshore ocean sailing sailboat

Boom preventer. Boom brake. Whatever you do, whatever you call it, having a way to prevent or dampen the force of the boom to prevent accidents while sailing deep downwind is important. A lot of cruising IS downwind, so thinking through a smart setup is critical! I’ll never forget learning about a boat some miles ahead of us on the Pacific crossing where a crew sustained life-threatening injuries after a crash gybe. Even a planned, controlled gybe tends to give me the willies due to the tremendous force involved: a violent, unexpected gybe can cause significant damage.

The sliver of a new moon wil set before we pull up Totem’s anchor tonight. Ahead is a challenging passage, one we’re not sure how far we’ll take: hopefully, all the way to Puerto Rico, if all goes well (follow our progress at our tracking page on PredictWind). Breeze expected is all forward of the beam, so there’s no need for a preventer– but recently someone asked about our setup. Jamie wrote it up, I took a few pictures to illustrate.

whale spout sailboat sailing ocean mountains

Whale-watching as we sail away from South Africa – preventer in place

DSC_7708What works for us will not right for every boat, but is a safe, strong, and reliable method on Totem. and I’m sharing here in case it helps others install or improve their own preventer. We like it because:

  • Simple approach
  • Side decks left uncluttered
  • No specialized/dedicated gear purchase necessary
  • Puts loads at points able to withstand them (mast/vang/midpoint of boom not intended for the shock loading involved- outboard end of boom is much better)
  • Quickly/easily released from the cockpit if necessary

Totem’s setup: Component Parts

  • 1 x boom lanyard – Dyneema single braid, with ¼” (6mm) diameter.
  • 2 x preventer lines – polyester double braid, diameter depends on sail area (Totem uses 1/2”). Polyester gives a little stretch, but not too much. Length depends on preventer block location and center or aft cockpit. Lines should be long enough that preventer set on one side can remain in place through a gybe.
  • 2 x Preventer blocks or low friction rings – we have blocks, but low friction rings are a great choice: they are more robust and lower cost.

Concept

A preventer must bear considerable loads; in the worst scenario, shock loads that will cause a weak link to fail. For this reason it’s safer to secure the preventer to the aft end of the boom. A middle boom attachment point is more likely to break the boom in an extreme situation.

End of boom attachment can make setup awkward/hazardous or require fixed preventer lines that will cross the deck and get in the way. This preventer setup splits the preventer line into two sections. One line is the boom lanyard; and the others are the preventer lines (1 on each side of the boat). The lines are out of the way when stowed and easy to deploy.

Boom Lanyard

sailboat boom

The boom lanyard is shown above as the line running below the boom. The aft end is spliced around the boom. The forward end has an eye splice to secure to the boom when not in use, as shown, and to use as an attachment point to the preventer lines. When stowed, it’s important to keep the boom lanyard tight along the boom because a drooping line can catch on something or someone.

Eye splice rope line lanyard

Eye splice at the forward end of the lanyard…and around boom on the aft end

This shows one end of the boom lanyard spliced around the boom and the eye splice in the other end. Boom lanyard length should be set as follows:

  1. Easy to secure to the vang attachment when not in use.
  2. Easily reaches the side deck when the boom is out, so it’s safe tying to the preventer line.
  3. Another use for this line is to secure the boom from swinging back and forth when not sailing.

Preventer Lines

sailboat deck

This view down Totem’s side deck shows one preventer line, stowed and ready for use. Things to note, besides those lovely clear side decks:

  1. One end of the preventer line is secured to the lifeline. The other end leads back to the cockpit and is coiled and ready for use.
  2. Fair leads are important! Note that one side of the preventer line runs outside of the lifelines. The other side runs aft along the deck and is NOT fair in this picture. You’ll see that in a later picture I reran this side to go between shrouds so it doesn’t chafe.
  3. The next picture shows me (Jamie) getting ready to connect the boom lanyard and preventer lines together. Note that I am pulling the boom outward for the picture; normally I would be sitting in an easier and safer position when underway. (Behan: you bet he would, or I’d be unhappy about it!)

sailboat

Secured to the toe rail with a Dyneema loop is the preventer line turning block. Friction is not an issue with the preventer, so consider a low friction ring instead.

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Location matters:

  1. Setting the block too far forward increases preventer line length and is hard to run fair.
  2. Setting the block too far aft makes a bad angle when the boom is all the way out.

Our blocks are set about 2 feet forward of the forward lower shrouds, a position that gives a fair lead and good angle to secure the boom.

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Above is a snapshot of the boom lanyard and preventer line, tied together and ready to use. Do not use a shackle! The knot is much gentler should it hit something or someone. This is especially true when you do gybe (by choice). Simply ease the preventer line to allow the boom to swing over.

andersen winch

The other end of the preventer line, ideally, goes on a self-tailing cockpit winch: ours goes to one of Totem’s spiffy Andersen secondaries. This approach makes a quick release easy if needed. If you don’t have an open winch here, you can cleat the line. Either way, be sure to coil the end of the line, and keep it clear to run freely in case you need to quickly release the preventer.

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Here’s the completed setup, much as it can be from our Bahamian anchorage! Notice how the preventer lead has been moved to run fair between the shrouds.

Boom brakes

For some boats, a brake makes sense. These don’t prevent the boom from crossing over, but dampen the movement. We’re not fans of this on Totem because it would place tripping-hazard lines on the side deck. But for other boats, other layouts, they’re a great option: the setup at our friend’s boat Akira, anchored a few boatlengths away, is a great example of this. Keeping it all on the coachroof means there’s no dangerous deck clutter, and they can handle it right from the cockpit.

green line runs to brake on boom, and clutch in cockpit

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I’m looking forward to having a passage that requires setting up the preventer, not this upwind stuff! But for now, will tackle the upwind days ahead by cooking up a storm, checking and re-checking all stowage, and loading books on the kindle from our hometown library.

Another cutthroat game of DogOpoly with crew from the Manta 42, Akira

Another cutthroat game of DogOpoly with kids from the Manta 42, Akira: having a lot of fun with this crew.

Adults in the cockpit, kids in the cabin, paparazzi mama.

With thanks to Bonnie,  for the question and for the kind donation to our cruising kitty!

Efficient Sailing: passage routing

3- asymmetric starboard

There’s a problem: many cruisers think that sailing performance isn’t important. Hey, cruising is about slowing down, right?! But dismissing performance is poor seamanship. Part two in a series.

Efficient sailing is partly about sail trim and sail handling (that’s covered here), and partly about routing. With a few rules, routing from A to B can be faster (and safer).

dsc_3791Big picture routing—should we take the northern or southern route across the Indian Ocean?—is fun and easy. String together an efficient and safe path to the places that you want to visit. Take into account big considerations: seasonal weather patterns, time limitations, access to fuel/food/etc. The scientific formula for big picture routing is: fun – harm = intentions. What you actually do depends on a millions variables that happen as you step along the path.

Zoom in on details of sailing to the next place and you’re into A to B routing. Sometimes this is easy; a straight path without complicating factors. Often subtle variables can cost you time or diesel, and elevate risk.

Going from Seattle to Friday Harbor, you look at the weather and the tide for when you expect to be at Cattle Pass. This is A to B routing. Practical experience from attempting Cattle Pass on the wrong tide (as we once did) indelibly marks this detail as one not to forget. There are many “Cattle Pass” lessons that you learn to incorporate in A to B routing. This is local knowledge and it saves time, money, and lowers risk. Venture to a new area and local knowledge is gone.

Fortunately, wherever you’re going, somebody went there and wrote about it. Many blue water cruisers reference Jimmy Cornell’s World Cruising Routes. It’s a fine book for big picture routing and guidance on A to B routing, but it’s not a roadmap.

Our passage in April from Ascension Island to Barbados was 3,100 miles long. The small group of boats doing this passage referenced Cornell, and set out with the author’s advice on crossing the equator between 28 and 30 degrees west longitude. Crossing further west into northeast trade winds can make the Caribbean upwind and hard to reach. This advice has the downside of being into a wider band of ITCZ, meaning more squalls. Off the boats went, one by one, aimed at 28 degrees west. We chose a different route.

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Landfall: Ascension Island

In A to B routing, the longer or more complicated the route, the more days in advance I study weather and variables. For weeks I studied several different GRIB models. Day after day, trade winds were not northeast as Cornell said, but east north east and just fine for getting to the Caribbean. Investigating a route along the coast of Brazil, 900 miles west of Cornell’s route, I found reference to a strong current flowing northward along the coast. Fine wind, less lightning (narrower band of ITCZ), and positive current was too good to ignore. PredictWind’s routing algorithms (that’s our track in their viewer below, automatically generated with pings from our Iridium GO underway) in the Offshore app concurred, and bingo, we were off to the Brazilian coast. It was beautiful sailing with very few squalls, averaging 180 NM per day over 17.2 days. The “book route” took boats 5 to 7 days longer, experienced more squalls, and burned a lot more diesel. Budget sailors can get similar routing through FastSeas, a free/donation tool based on NOAA data for GFS and ocean currents.

pw path

After this passage I happened to reread Slocum’s Sailing Alone Around the World. In 1898, Slocum sailed Spray on the same route along the coast of Brazil to reach the Caribbean in good time, noting, “the current, now at its height, amounted to forty miles a day.” Eighty-nine years later, Jimmy Cornell missed or disregarded this current. His book is still a great resource, but scenarios like this are a good reminder that it’s only one static resource.

From this lesson and others, here are six rules for A to B routing.

  1. Use multiple data sources.
  2. Schedules are inconvenient.
  3. When weather sources disagree, don’t pick one as best.
  4. Consider tidal and current flow.
  5. “Group think” weather analysis is always one opinion to many.
  6. Forecast accuracy varies regionally; compare forecasted and actual weather over time.

Efficient sailing will get you there faster, safer, and with less wear and tear. Just don’t confuse it with performance sailing! That can lead to soggy spinnaker and sour party mood.

This post was contributed by Jamie, who shares his more technical sailing experience from time to time. It’s really two legs on a three-legged stool, because routing is as important to efficient passagemaking as sail trim and sail handling…that post will have to come later.

were-in-annapolis

Cruisers should care about performance sailing

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There’s a problem: many cruisers think that sailing performance isn’t important. Hey, cruising is about slowing down, right?! But dismissing performance is poor seamanship. After some years of listening to cruisers disregard performance and gripe about slow passages, it dawned on me that confusion is to blame.

Our good friend William demonstrated this last year during a fun race in Madagascar. William is a good sailor with much blue water cruising experience. He doesn’t race, but his competitive side, or maybe his social side, was piqued by party and prizes to follow the competition. With his racing cap on he chose a bold spinnaker start while single-handing. It didn’t go well. The gun cracked and his spinnaker tangled, slipped, and dipped…he did not have a good race. On passage William is slow and deliberate when setting a spinnaker, a pace that isn’t very racer-like but ends with a performance boost. Had he stuck with this instead of confusing performance and racing, he would’ve had more to celebrate at the party.

To clarify this issue, let’s forget all about performance; and instead, talk about “efficient sailing.” A rabbit in a bunny suit is still a rabbit, so what’s the point? Comfort and safety come with avoiding or minimizing bad weather, and stress comes from contemplating a three day passage when weather windows only last for two days. Efficient sailing is getting from A to B with minimal effort. What could be more appealing to a cruiser than minimal effort!

Making landfall in Comoros, Indian Ocean

Making landfall in Comoros, Indian Ocean

Racing sailors are pedantic about sail trim. Constant adjustments can yield subtle gains that show when measuring against competitors. We’re not interested in subtle gains. Reasonable sail trim takes no more time than bad sail trim, but yields better speed with less wear and tear to sails.

For example, when reaching and running, a boom vang locks the boom from lifting and dropping due to changing wind pressure on the mainsail. This may seem insignificant, but not using a vang slows you down and will cost you money in repairing a mainsail chafed by rubbing against rigging.

Another example is headsail trim. Sheet blocks are often set for reasonable trim going upwind, which fine, except that most of the time cruisers aren’t sailing upwind. When using an upwind sheeting point for reaching and running, the upper portion of a headsail twists to leeward, spilling wind causing the upper leech to flap. A barber hauler is an easy way to trim the headsail correctly for broader wind angles. This gives a considerable boat speed boost that can be 10 miles and more per day.

brberhuler

Both barber hauler and sheet are used for max efficiency at the wind angle

Racing sailors are well practiced at sail handling for fast transitions. Fast is usually not important or practical for short-handed cruisers, like our friend above. Efficient sail handling from a well setup boat, practice, and good crew communication reduces crew risks and equipment breakages.

Step one is setting up the boat to make sail handling easier. Cruising boats are usually reasonably well set up, but it takes time on the water to learn what works well and what needs improvement. Friction causes the most trouble. Friction makes you weak, and swear like a sailor. I installed a Harken furling system for cruising friends in Singapore. The next day they had words with me because furling was harder than ever. I went back to their boat and tested each furling line guide blocks. Only one of them actually turned, and the rest were easily fixed with fresh water and silicone spray.

Keep winches, blocks, and sheaves in good order. Watch for line chafe and metal fatigue. And give thought to unplanned sail handling events – they happen. When Totem was ghosting along the Pacific ITCZ, the heavy duty stainless steel pad eye securing the mainsheet to the boom sheared off. The part was less than a year old, and failed from slatting force. By chance, I had installed a webbing strop around the boom just in case such a thing happened. The mainsheet was reattached in just a couple minutes.

strop

Pacific, between Mexico and Marquesas. Bonus squall. Rather undesirable twist in the mainsheet….

Step two of efficient sail handling is matching sails to the conditions. This may seem obvious, but it’s common to see people raise the anchor and hoist full sails; then outside of the protected anchorage, bigger wind hits and they scramble to reef the main. This is almost like sport in the eastern Caribbean this spring watching boats poke out from the lee and into the channel between islands. Start the day with a weather forecast and a few moments of observation before getting underway, and don’t forget the impact of geography.

Once underway, reducing sail area is all about observation and timing. In 20 knots of true wind, I can reef our mainsail on my own in 2 minutes –less if more motivated by approaching squall. In 30 knots it takes at least twice as long. Monitoring wind speed and watching for obvious changes (like squalls) and subtle changes (such as increasing gusts) gives you time to adjust sails when it’s still easy.

Approaching the South African coast last November, we expected landfall 6 to 12 hours ahead of forecasted bad weather. With 20 miles remaining of the 1,000 mile trip, we were sailing in gentle conditions with a perfect sunrise, and feeling good. Then I looked up. Above a thin layer of clouds going our way, clouds whipped along in the opposite direction. Bad news: the southerly buster came early! Engine on, we prepared for strong headwinds. At 7 miles to go, wind was 25 to 30 knots on the nose and against the strong Aghulas current. Waves piled up with no gap between them, and our speed dropped under two knots bashing into them. It was a tedious few hours getting in, but each additional hour out there would have been worse.

This post was contributed by Jamie, who shares his more technical sailing experience from time to time. It’s really two legs on a three-legged stool, because routing is as important to efficient passagemaking as sail trim and sail handling…that post will have to come later.