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FPB 97-1 <\/em>Iceberg running before a stiff breeze during sea trials.<\/em><\/p>\n The post that\u00a0follows this introduction is a chapter excerpted from the FPB 70 and 78 Owner\u2019s Manual.\u00a0Everyone who goes to sea thinks and\/or worries (or should) about heavy weather, and how their vessel will handle different conditions. It doesn\u2019t matter whether you\u2019re on a 25,000 ton container ship, a moderate-sized sailing yacht, or one of our FPBs. We think it is better to discuss these issues openly, rather than ignore them and hope you never get caught. We are sharing this chapter here because there are certain universal tenets when it comes to avoiding and\/or handling heavy weather that apply to all types of craft.<\/p>\n We would caution readers that, in the material that follows, while there are many principles that apply in some form to most ocean going yachts, the tactics and details listed below are FPB specific. It should also be noted that sea states we might consider to be an exhilarating challenge, from the security standpoint of our FPBs with their stability curves, surfing ability, and steering control, would be thought of as\u00a0survival storms in other types of vessels. At the end of the day, your\u00a0definition of heavy weather will depend on the experience and psychological state of the crew and captain, along with the capability and condition of the yacht.<\/p>\n We invite you to share your own heavy weather experiences via the comment section at the end of the post.<\/p>\n FPB 70\/78 Owners\u2019s Manual: Heavy Weather Preparation, Avoidance and Tactics<\/strong><\/p>\n Understand Weather<\/strong><\/p>\n The single most important thing you can do towards successful cruising is to get a feel for onboard weather forecasting. This helps you stay out of unpleasant situations in the first place, get a handle on the storm structure from onboard observation, and then adopt the correct tactics. It also pays dividends for picking anchorages and knowing when to get out. At the end of this post you will find URLs where you can download free copies of our Mariner’s Weather Handbook<\/em> and Surviving The Storm<\/em>.<\/p>\n Access to weather models and professional weather routers are a help, but this is no substitute for what you can deduce by tracking barometric pressure, wind direction, wind speed, and cloud types. And in really difficult conditions your onboard forecasting capability is absolutely critical to making the best use of the tools which the FPB puts at your disposal.<\/p>\n If you think that a shore-based weather router will save the day, think again. Modern weather forecasting tools can be quite accurate in terms of energy flows over wide swaths of the Earth. But when you focus down to the area where you are located, there can be major\u00a0variations between what you observe and what the weather models and\/or router has predicted.<\/p>\n (The sketches above are excerpted from <\/em>Mariner\u2019s Weather Handbook.)<\/em><\/p>\n This is not to say that professional routers are not a valuable resource. Quite the contrary. But we feel safest if we are in a position to frame the context in which they create their forecasts, and then discuss the variables and risk factors. In this regard, we have found it necessary to impress on forecasters\u00a0the high average speed we are capable of maintaining, along with what we consider acceptable sea states. This will be quite different from\u00a0their usual yacht clients – power or sail.<\/p>\n Here are a few items to be sure you understand:<\/p>\n We guarantee you that expending the effort to understand these factors will be the best investment of time towards safe and comfortable cruising you ever make.<\/p>\n Weather tends to be pattern-based. There is often a rhythm to the progression of highs and lows. These patterns will vary from year to year. We have found it helpful to begin watching the weather closely three to four weeks ahead of our desired departure date, to familiarize ourselves with how the season is working out. It often helps to chat with local met experts to get their take on the patterns they see and how these may vary from the norm. On occasion an upper level feature will establish itself where it spits out a continuing stream of atypical unpleasant weather. In this case it may be best to be patient.<\/p>\n An example of this is the passage from New Zealand to Fiji, where departing with the leading edge of a high usually guarantees a quick and easy trip. Your 4.5 days (or less) underway typically keeps you within the benign influence of the high. Even more important is getting north of the storm track, which takes 2.5 to 3 days.<\/p>\n Another example is heading east to French Polynesia, leaving on a leading edge of a high pressure system. As long as you can average 10.5-11 knots, in most cases you will see no more than one weather system sandwiched between two highs.<\/p>\n Here is what John Henrichs, one of our most experienced and sea savvy owners, has to say:<\/p>\n \u201cWatch the trends and once you are satisfied, contact your professional and see what they think about your departure date. If the professionals say don’t go, then you need to figure out what you missed and learn from it.\u00a0I find the more I learn, the more often I am challenging the router to explain more, and the last couple passages, I found things the router didn’t pick up. Not that I am better, but after 5 seasons crossing the same areas I keep learning more about the area. I would add to never stop asking questions from cruisers that have far more experience in areas than I do.”<\/span><\/p><\/blockquote>\n Steve Parsons, a professional sailor with extensive FPB 64 and FPB 78 experience adds:<\/p>\n “Given the speed and efficiency of the FPB, there would usually be no reason to get ‘caught out’ on a passage of 3 days or less, it’s really the longer passages where you have to deal with what you get outside of the long range forecast.<\/p>\n Studying weather patterns long before your expected departure is time well spent. Also try to have a plan for alternative ports, although this isn’t always possible. Follow a range of online forecasting sites; by studying 4 or 5 it is easier to spot any anomalies by comparison, especially outside the 72 hr forecasts, at which point they can be much less reliable. In NZ\/Pacific waters, we tend to use Metservice, Metvuw, Passage Weather, Predict Wind, and Grib Files. It is a valuable learning exercise to study an isobaric analysis, draw your own 24\/48 hr forecast, then compare it to the prognoses. This is a useful way to familiarize yourself with local weather trends. Weather routers can be a useful ancillary tool, but remember, as has been stated elsewhere, no one knows the local conditions better than the person who is actually in those conditions and knows how to read the sky and seas.<\/p>\n Finally, a word on high pressure systems and your boat speed. Once you can average ten knots or more it becomes possible to ride high pressure systems towards your destination, or cross them while they block unpleasant weather. The high may\u00a0be moving at 12 to 15 knots or it may be stationary, but the faster you go the longer you benefit from it.”<\/p><\/blockquote>\n Vessel Preparation<\/strong><\/p>\n Most major sea going problems start out small. Really serious issues, in particular those associated with extreme weather, are usually the result of a cascade of events, the beginning of which was preventable.<\/p>\n Take care of anything that\u00a0can impact your speed, steering, and watertight integrity before you leave. We always inspect steering gear, including fastener torque on cylinders, tillers, drag links, etc. The drive line and high load engine accessories are checked. A detailed check list applicable to your own vessel is recommended.<\/p>\n Insure that interior storage areas are appropriately stowed and deck gear is\u00a0all lashed in place, under the assumption that unpleasant weather is on the horizon. If you have large areas of storage, such as in the FPB 78 forepeak or FPB 70 basement, pay particular attention to storage security. Heavy gear that comes adrift can do significant systems damage.<\/p>\n Inspect the boom control hardware and the securing of the booms themselves. Where there are boom control struts, as on the FPB 78, check bolt torque on boom connection collars, track bolts, and articulating ball joints at strut ends.<\/p>\n There should be nothing lashed to the foredeck unless it has been properly engineered, i.e. the secondary anchor. Dorade vents should be secured from the interior, and cowls removed with solid covers inserted.<\/p>\n Rig jack lines on the exterior, and extra manlines around the aft deck and interior. Dinghies may benefit from\u00a0a secondary set of lashings.<\/p>\n Finally, the single biggest impact on boat speed and maneuverability is the condition of props, fins and hull. Take the time to have these cleaned before every passage.<\/p>\n Practice<\/strong><\/p>\n We recommend testing various wave angles, steering settings, speeds, and crew whenever the opportunity arises to give the boat a good workout. Lying a-hull with and without stabilizers, heaving-to with and without them, and jogging are all worth practicing.<\/p>\n Experiment with different boat speeds while jogging into the seas. Imagine a breaking sea suddenly coming from your beam (i.e after a frontal passage). You will probably find a combination of rudder and throttle is required to make the fastest 90-degree turn.<\/p>\n Put in some time steering with the emergency JOG lever (which gives you direct control of the rudders without autopilot finesse). Experiment with this upwind, cross wind and downwind.<\/p>\n The rudder speed doubling \u201cdocking pump\u201d, which brings a second hydraulic pumpset online, will often be beneficial in weather scenarios requiring aggressive steering.<\/p>\n If you carry parachutes or drogues, the crew should be familiar with their deployment and retrieval.<\/p>\n Payload<\/strong><\/p>\n Each FPB type has an optimum loading for heavy weather. Carrying payload greater than this amount can be a negative. It slows you down, makes the boat less responsive to helm, reduces usable downwind speed conditions, and makes the boat more susceptible to wave impact.<\/p>\n The FPB’s massive fuel and water capacity make it easy to overload. Generally speaking, if you are heavy with fuel, go very light on water. Replace the mass of fuel as it is burned with water. If the water maker fails, you can always introduce salt water into an empty fuel or water tank as an emergency replacement. In worst case situations, salt water can be mixed with the understanding it is going to take a while to clean up the resulting mixture.<\/p>\n Press Tanks<\/strong><\/p>\n A partially filled tank creates substantial free surface loads, which reduces your stability. This is most acute in near-knockdown situations. Manage fuel and water so that tanks that are being used remain filled other than the one from which you are drawing.<\/p>\n Longitudinal Trim<\/strong><\/p>\n Generally speaking, each FPB has an optimum trim angle for maximum efficiency in normal sea states. However, when you are contemplating bigger sea states, steering control and minimizing propeller air entrainment become the dominant criteria. Both of these favor stern-down bow-up longitudinal trim.<\/p>\n Autopilot Settings<\/strong><\/p>\n The Simrad pilot is easily programmed for different steering modes. At present you can have six of these. On Cochise<\/em> we have one setting called Heavy Running and another called Maneuvering. Heavy running is self explanatory. Maneuvering is normally used just for docking, but would probably also work well in severe upwind slow jogging conditions.<\/p>\n NAIAD Settings<\/strong><\/p>\n Whether the fully automatic \u2018adaptive\u2019 or modifiable \u2018at speed\u2019 settings work best will be determined by trial and error over time. In a heavy weather context watch out for excessive stabilizer angle, which leads to stabilizer fin stall, and the accompanying momentary loss of speed from the greatly increased drag.<\/p>\n If the Stabilizers Fail<\/strong><\/p>\n We have been lucky so far with few underway stabilizer issues. But if they do fail there are several things to consider. First, be sure the fins are locked on center. Be aware that with fins centered, abrupt directional\u00a0changes\u00a0will cause the centered stabilizers to generate lift forces that will heel the boat, so limit steering input to a minimum.<\/p>\n Choose a course that avoids beam or nearly beam seas, and avoid angles that expose you to harmonic rolling (where your natural roll period is a harmonic of the wave period).<\/p>\n Experiment with different speeds. Generally speaking, faster is normally more comfortable than slower.<\/p>\n Check the Route<\/strong><\/p>\n Have a close look at the various route options for deep underwater obstacles and navigate\u00a0around these if there is any risk of surface interaction. An underwater ridge that goes from a depth of 5,000 ft to 1,000 ft can set up a chaotic sea state, sometimes in relatively benign conditions.<\/p>\n Use Your Seat Belts<\/strong><\/p>\n Your FPB is equipped with seat belts on the bunks and in several seating areas. Use them! They will keep you much more comfortable and prevent bodies from flying around after major wave impacts.<\/p>\n Psychology and Remaining Alert<\/strong><\/p>\n It is not unusual for a crew that is\u00a0tired and deeply concerned with the situation to be unable to make decisions. The boat is left to its own devices, and the risk profile increases.\u00a0Confidence in your equipment, which comes from preparation and practice, helps keep your mind at ease, and rest is a powerful antidote. Husband your energy early on. You may need it later in the blow. Finally, we have found that food is a great morale booster. An inventory of easily warmed pre-cooked meals and snacks can do wonders.<\/p>\n Tactics<\/strong><\/p>\n There is no magic bullet, no single tactic that can be used in all situations. As wind and sea conditions change your strategy\u00a0may need\u00a0to adapt as well. The worse the situation, the more involved you will need to be. You cannot close your eyes and wish the conditions away.<\/p>\n Be particularly alert if the wind suddenly dies as the sea state, now without wind pressure, can become chaotic. Wait until the sea state has stabilized–it\u00a0will eventually drop over time–before relaxing your vigil.<\/p>\n Keep in mind that the FPB gives you the ability to maintain high average speeds through a variety of adverse wind and wave scenarios. Thus, you have a much wider range of options than you may have been used to with other yachts. In particular, you may have the ability to change position within the storm to reduce risk from wind, wave, or navigation obstacles.<\/p>\n In the most extreme conditions, the tactics that you employ will ultimately depend on your stability and the capability of the yacht to deal with breaking seas. All yachts have their greatest stability when taking seas end-on, either bow or stern into the wave, and the least stability when beam-to.<\/p>\n The photos which follow were taken in 35 knots of wind as FPB 64-1 Avatar<\/em>\u00a0was leaving Whangarei, New Zealand. The river tide is ebbing against prevailing wind and seas, hence relatively steep waves. Avatar<\/em> is fully loaded for her first trip to the tropics and she is running at just under 11 knots, showing off for photographer Ivor Wilkins.<\/p>\n In this first shot Avatar is doing what she is supposed to do, penetrating the wave.<\/em><\/p>\n Now a series, climbing a larger sea.<\/em><\/p>\n She is now partially airborne.<\/em><\/p>\n And now almost fully airborne.<\/em><\/p>\n In this spectacular (albeit unusual) return to the trough\u00a0it looks like there’s a lot of water coming on deck, but in terms of stability or structure, it’s a non-issue. Note that the layout of the foredeck, and elimination\u00a0of deck edge bulworks, makes it nearly impossible to accumulate significant quantities of water.<\/em><\/p>\n Sometimes moving the boat at speed from one position to another will feel like your FPB is being really punished. If you are wondering what sort of a pounding these hulls can take, your feet will give you a sense of what is going on. When you are in the Great Room, and your feet stay on the sole when you drop into the trough the forces are less than one \u201cG\u201d. You are not yet beginning to tax the boat.<\/p>\n The boat can take a lot more than the human body. In the process of moving your FPB, you may think you’re beating the s**t out of her, but she is perfectly happy.<\/p>\n The above photos and discussion are in the context of moving the boat to avoid the worst parts of a severe weather scenario. Here is a list of some items to think about:<\/p>\n Wind and sea states typically vary, sometimes substantially, around the center of a storm system. The more speed and steering control you have at your disposal, the greater your options of improving the conditions with which you must deal.<\/p>\n Most tropical systems (typical hurricanes) have their strongest winds within a 30-to-50 mile radius of the center. Where you might have 80-knot winds 20 miles from the center, at 50 miles you might be down to 35 knots.\u00a0Extra-tropical storm systems are much larger. But even here a couple hundred miles can make the difference between an interesting experience and survival conditions.<\/p>\n Speed and Maneuverability Are the Keys<\/strong><\/p>\n At the risk of sounding like a broken record, boat speed and steering control are the key ingredients in determining which tactics make the most sense. When running off, the faster you go the fewer waves overtake you, and the more time you have to react to them. Your rudders and stabilizer fins generate force in proportion to the square of the boat speed, so small increases in boat speed go a long way in helping with control. If you are running at 9.5 knots and up\u00a0the RPMs to where you are surfing at 13.5 knots, your fins will generate twice the force.<\/p>\n Watching Waves – Visibility at Night<\/strong><\/p>\n Our experience is that you can often see large crests some distance off, even on moonless nights. With a bit of moonlight and dark adjusted eyesight, you will usually have a pretty clear indication of what is coming.<\/p>\n In really difficult sea states, given sufficient crew, the ideal is to have one person on the controls and a second calling dangerous waves. And of course there are the LED flood and spotlights forward that will help as well. In fact, an extra set aimed aft could\u00a0pay big dividends in heavy downwind running.<\/p>\n Steering Around Dangerous Seas<\/strong><\/p>\n Dangerous seas sometimes have escape routes, areas along the wave face that are not breaking or have smaller crests. There are times when the transition region is abrupt, sometimes even vertical. With sufficient boat speed and maneuverability plus situational awareness, you can take advantage of these escape routes, as shown below\u00a0in the excerpt from Surviving the Storm<\/em>.<\/p>\n Skid Factors<\/strong><\/p>\n All of the FPBs are designed to skid sideways under wave impact as they begin to heel (as in all of our sailboats). Skidding allows the yacht to\u00a0absorb the energy of breaking seas over time, like slipping with a punch in the boxing ring. The ability to skid enhances survivability regardless of a yacht’s\u00a0stability curve. Here are a few skid design factor considerations:<\/p>\n Running With the Wind Aft<\/strong><\/p>\n <\/p>\n <\/p>\n Given clean running gear, fins and hull, and moderate loading, it will be unusual to encounter conditions where you cannot continue to run directly downwind at speed, having great fun surfing.<\/p>\n 10 to 15\u2019 (3 to 4.5m) waves like these from the stern quarter don\u2019t begin to register on the adrenaline scale (FPB 83-1 <\/em>Wind Horse en route from New Zealand to Fiji).<\/em><\/p>\n Assuming downwind is where you want to go, this is often the best way to get yourself off the storm track. This is another example where your understanding of the weather system you are dealing with is essential.<\/p>\n The FPB 78 and 70 have extra freeboard forward, and the positive angle of attack this gives the belting (rub rail) and anchor platform creates dynamic lift if the bow is buried into a wave.<\/p>\n There are two scenarios we have found where it pays to start thinking about heading upwind. The first is if there is a danger of driving the bow deeply into the back of the wave ahead of you as you surf at too high a speed. If this results in a rapid deceleration, and the wave behind you breaks as you are slowing, a pitchpole or severe broach is possible.<\/p>\n The cresting sea in the middle background, if it caught the bow or stern, would require significant rudder input to maintain heading. It is about twice the size of the average waves. Check out the sea further out at the horizon. The first two days of this passage to Fiji aboard <\/em>Wind Horse we\u2019d see these every hour or two, but never came into actual contact.<\/em><\/p>\n When running at high speeds with crossing seas and\/or steep waves, adjusting course up from a dead run may reduce the chances of \u201cstuffing\u201d the bow. When the decks start getting wet with solid water, that is a signal\u00a0that something needs to change.<\/p>\n No longer being able to control direction of travel is another sign that it’s time to think about different tactics.<\/p>\n Speed, surfing, wave shape, and steering are all linked.<\/p>\n Sometimes adding RPMs will result in faster speed and better control. Other conditions may warrant a bit less RPM, with occasional RPM increases to help with steering. Sea state and wind speed tend to change constantly, and it is not uncommon to need to play with RPMs and course.<\/p>\n During sea trials with FPB 78-1, we found ourselves in a rapidly increasing 35-50 knot breeze as we headed north to the Bay of Islands. Cochise<\/em> was lightly loaded at the time, carrying approximately 2500 gallons of liquids. Towards the end, with the steepest seas, we were running at 2000 RPM with surfing speeds consistently at 13.5-22 knots. There were several times when we overran the wave we were riding and buried the bow right to the belting in the back of the wave ahead of us; in none of these cases did we ever pick up any solid water on deck. On three occasions we started to round up off course 10-20 degrees, with heel to 15-30 degrees, a situation in which you would expect a broach. However, each time the autopilot steered us back on course with our speed in the high teens or above, never dropping. In thinking about this after the fact, we realized that the key to Cochise\u2019s<\/em> ability to steer her way out of these incipient broaches was her boat speed. Anything significantly slower and we would have been testing our skid factors. However, if we had been in the open ocean and there was a crossing swell, we would have had to reduce our surfing speeds\u00a0to maintain control.<\/p>\n There is a short video below that is intended to be watched with this section. It will give you an idea of what the FPB 70 and FPB 78 are capable of when surfing at high speed.\u00a0Cochise<\/em>\u00a0is close enough to shore that there is a\u00a0periodic cross chop from reflected waves. We are pushing very hard, looking to define the limit of her maneuverability\u00a0when surfing at high speeds.<\/p>\n The video focuses on rudder angle, course over ground, boat speed, and heel angle. Watch how the autopilot brings\u00a0Cochise<\/em>\u00a0back onto course with minimal rudder input, very little change in speed, at heel angles as high as a momentary 30 degrees. The way in which this all works is an indicator of how hard you can push. We think we are close to the limit for this type of situation.<\/p>\n At the end of this post is a link to the longer video from which this extracted.<\/p>\n![\"mwh_sketch1\"](\"https:\/\/setsail.com\/wp-content\/uploads\/2017\/07\/mwh_sketch1.jpg\")
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Although the preceding is in the context of extreme conditions, skidding also works in more moderate sea states, making for a more comfortable passage and less heel when those occasional over-sized crests meet up with your topsides.<\/div>\n<\/div>\nThe FPB 70 and 78, with their next-generation hull shapes, have slightly different skid characteristics than their predecessors. Depending on payload, you will find that they will initially absorb somewhat more energy before beginning to quickly slip to leeward, but then slip a little more easily at higher heel angles.<\/div>\n![\"FPB-831-Wind-Horse-big-seas-101-of-4\"](\"https:\/\/setsail.com\/wp-content\/uploads\/2017\/07\/FPB-831-Wind-Horse-big-seas-101-of-41.jpg\")
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