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Old 11-05-2003, 23:03   #1
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Boat: Farr 11.6 (AKA Farr 38) Synergy
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Synergy, a Farr 11.6

Synergy is a Farr 11.6 (Farr 38). I posted pictures of her in the gallery.

The Farr 11.6's are interesting boats. They were built as cruiser/racers, and offshore cruisers and in their day they were extremely fast compared to other 38 footers that could be cruised. Compared to cruiser/racers of that era, they were very light. With a design weight of only 10,600 lbs., they were 2/3 of the weight of a normal 38 footer. In some ways these were boats with a split personality. Sisterships are distance cruising all over the world. My boat, for example, was single handedly sailed in from South Africa on her own bottom. Yet, at the same time Farr 11.6's are also winning races.

I chose the Farr 11.6 in a bit of an unusual manner. It is very common for people to search for boat solely on length and the need for specific accommodations. I really think that the displacement of a particular boat says a lot more about its 'real' size. To narrow the field of possible model choices, I went back to some time honored formulas. I looked at the traditional rule of thumb that a proper cruising boat needed a displacement of three to five long tons of displacement per person. In recent years, Better hardware has permitted that ideal weight to creep up a little and the current trends in loading boats up with modern equipment and all of the comforts of home, has pushed that range up to closer to 11,000 to 14,000 lbs. of displacement per person. I personally prefer to cruise more simply and so chose to try to stay in the low end of more traditional weight range. With a crew of one or two people this suggested a boat with a displacement in the 11,000 to 14,000 lb. range.

Historically, a cruising boat with a 5 to 7 ton displacement would have been 32 or so feet in length. When you look back at earlier distance cruising couples, they tended to use boats that were comparatively short when compared to the norm today. This shorter length resulted in a high length to displacement ratio (L/D) typically in a 250 to 350 range. These old style cruisers were typically pretty shallow, and carried a larger percent of their weight in their hull and rig resulting in a lower ballast to weight ratio and consequently less stability. As a result they also tended to have less sail area and lower aspect ratio rigs in proportion to their displacement with a SA/D ratio in the range of 14 to 16 or so.

But using modern materials and a better understanding of marine structures and hydrodynamics a 5 to 7 ton cruising boat can safely have an L/D of 160 or so and still have a higher ratio of ballast to displacement than its predicessors. This lighter L/D typically means a more easily driven hull and the greater ratio of ballast to displacement placed lower in the water can result in the ability to carry more sail. On more modern designs a SA/D ratio above 20 is not all that unusual. That combination means that the boat has enough sail area to sail at a reasonable speed in light air and an sufficiently easily driven hull to get by with less sail area in a blow.

Using the lower end of the classic displacement rule of thumb, 10,000 to 16,000 lb of displacement seemed right for a couple. Using a more modern and lighter L/D near 160, I ended up with a 37 to 39 foot boat. For other reasons, I had decided that 36 to 39 feet was about the right length as well. Smaller than 36 feet it is hard to get the kind of accommodations and capacities that I wanted in lightweight boat. Over 38 feet or so, single-handing became considerably more difficult. Staying at a traditional weight range but lighter L/D results in a longer boat which is also good thing. One thing that has consistently come out of the studies of the Fastnet tragedy and the Sidney-Hobart disaster, is that there are a lot of factors that determine whether a boat is a good sea boat or not, but nothing succeeds in heavy weather like length.

You often hear the old saws about heavy displacement being necessary in a cruising and comments such as, "light boats don't have the capacity to carry enough gear and supplies to really go cruising." Or "they loose their speed advantage when loaded to go cruising". These kind of statements ignore that boats in this size range are often raced with 1,500 to 2,000 lbs. of crew weight and in distance racing, an equal weight in racing gear and provisions for this crew.

In terms of rig, I strongly prefer a fractional rigged sloop which I consider to be the ideal cruising rig for a boat of this size. Their proportionately smaller headsails are easier to stow, fly and tack. Because their jibs are a proportionately smaller part of the overall sail plan, fractional rigs can often have a greater wind speed range for each headsail and get by with non-overlapping jibs. For single-handing the greater ease of tacking a non-overlapping headsail can't be beat. Another advantage of a fractional rig is that the simple application of backstay tension can induce controlled mast bend which depowers both sails at once which often balance the helm and thereby reduce the need to reef. Fractional rigged boats also can be generally sailed under their mainsails alone making a very handy rig for short-tacking your way in a confined area or dealing with a sudden increase in wind speed.

Jeff
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Old 12-05-2003, 13:50   #2
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Fractional rigs

Hi Jeff,
I've read a lot of your posts on Sailnet and always have wondered what your S/V was like. I just looked at the pictures and it looks very similar to my S/V (TRIX - posted pictures also). Mine is a 40 footer, but only because of the long transom. The hull seems to have much of the same shape and her displacement is 14,000 lb. As for the factional rig, you must need at least two reefing points for such a large main. What is the "J" dimension on the Synergy? It's kind of like half a Cat rig. For single handing I can see the advantages, relying mostly on one sail.
You mentioned that longer vessels fair better in rough weather because of the hull length even with light displacement. Have you experienced that personally or is that through formulas/tests.
Synergy looks like a sweet vessel worthy of praise........_/).....
DelmarRey
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Old 12-05-2003, 22:35   #3
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Boat: Farr 11.6 (AKA Farr 38) Synergy
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Thank you for your kind words on Synergy. To perhaps talk to a few of your points, Trix looks like a neat boat. She appears to be an early IOR III era raceboat which is an interesting contrast to the Farr 11.6's. IOR III resulted in some of the faster IOR type boats. Because of the measurement points contained in the IOR rule these boats had a hull form with a fairly deep canoe body and with their center of buoyancy pretty far forward.

The Farr 11.6's were probably designed about the same time as Trix (around 1980 or so) without consideration for any particular racing rule and were in many ways the precurser to Farr's early IMS boats in terms of its hull form and minimal foil areas. Both boats represent a moment in yacht design history when design thinking was evolving. Trix represents nearly the highest refinement of the IOR rule and the Farr 11.6 represents perhaps one of the earliest iteration of the IMS typeform.

Boats like the Farr 11.6 were designed in response to the Fastnet Disaster, which had occurred just a few years earlier, and which had revealed the short comings of the then popular IOR rule. Designers began looking to develop raceable boats that were more seaworthy and comfortable in a seaway. They began by increasing ballast ratios and dramatically lowering the vertical center of gravity, fining out the bows, increasing waterline length, modeling the sectional properties to avoid the pitfalls of a high for stability large flare hullforms.

While the Farr 11.6 is very early in this evolution, and so is not as successful a design as the current crop of the raceboats, the impact of this change in design philosophy can be felt when thrashing into a short chop, running or power reaching. The motion is much more comfortable than on similar era IOR boats and she does not develop the downwind squireliness that was so characteristic to IOR boats. These early IMS style boats were considerably faster than equal length IOR boats of the era and were much easier to sail with substantially smaller crews.

Like any 38 footer, Synergy has two sets of reef points (plus a flattening reef in her delivery mainsail which is an old shelf foot main). Because she spent so much time offshore she also carries a storm trisail on its own track and has a storm jib that raises in the roller furling jib headfoil with retailer strops that act as secondary hanks.

The P (mainsail hoist) on the 11.6's is 45 feet. The E (mainsail Foot) is 18 feet.
The J is 13'-4"
The I is 43 feet

In one design form these boats carried a penalty spin pole and had a spinacker hoist well above the forestay.

It is interesting about how the 11.6's are sailed. Because she is a fractional rig I do not need to reef her in true winds up to around 20 knots or so. (25 or so knots apparent upwind). Up to that windspeed I can generally get by with lots of backstay tension and blading out the sails. In that windspeed I would be using #3 genoa which is wonderfully handy sail. I carry a single reefed mainsail and this blade jib well up into the 30 knot wind range upwind. In the one sail that we had in winds approaching 40 knots true, we simply carried a single reefed mainsail which took us upwind at around 8 knots and allowed us to tack through 70 degrees or so. We were in a very short chop beating up a comparatively narrow river with just two of us on board so this was a nice snug, easy to tack rig. Once we bore off onto a reach I rolled out the blade and we really had a sleigh ride staying above 10 knots and hitting speeds in the mid to high 11 knot range.

My comment about a longer vessel having greater seaworthiness came out of a paper that I heard delivered which analyzed all of the race disaster reports going back to the Fastnet and then subsequent research which included tank, model and full sized vessel testing. It would appear that there are really four common factors that were most critical to the comfort and survival of the boats involved. These were overall length (measured on the waterline in some reports and on deck in others), vertical center of gravity, not having too much dependence on form stability, and having the boat hold together.

Respectfully,
Jeff
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