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  #1  
Old 06-14-2005
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Fat Ass Sterns II

While talking with one of my dock mates this weekend we discussed the designs of new production sailboats, of which he happens to own. He has one of the more expensive boats (hint made in Ohio) and commented that when the boat is healed over the whole stern lifts so far out of the water that he notices significant loss of rudder control as it too is lifted out of the drink. He noted that he has a huge aft cabin and realized that the quirky sailing characteristics were most likely a compromise related to the interior volume gained at the stern of the boat. Why does this design appeal to so many and will they ever revert back to a "somewhat" pinched stern that are easier on the eyes and sails better? I still think the design of the new boats is butt ugly and don''t care what the around the world single hander are sailing. Has anyone else noticed the loss of rudder control?
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Old 06-14-2005
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Fat Ass Sterns II

I have one of those fat assed boats too. Funny thing... everytime I have too much canvas up she heels over too much the rudder cavitates and I spin out. Now that I think about it that happened to the other 25 or 30 differnt boats I sailed too. Don''t be a Ludite Denr. You still have tailfins on your car? Boats are desiged that way because that is the most efficiet hull shape, not for the sole purpose of a large aft cabin. You will notice that the forward sections on these boats are much narrower and the forward cabins are way smaller than they used to be. It works, thats why they do it. As for aesthetics, that is in the eye of the beholder. You could always find yourself a wooden schooner with tanbark sails. They will not go back to the old CCA types except for "character" boats nor should they. I''m looking forward to the next design wave. God only knows what they''ll look like.
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Old 06-14-2005
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Fat Ass Sterns II

The owner I was discussing the subject with previously owned an Ericson 32, he claimed that this boat DID NOT behave in the same manor as the new Tartan does when heeled over in a blow. Sounds like you''re trying to obfuscate the issue.
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Old 06-14-2005
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Fat Ass Sterns II

Will they go back to pinched sterns?you bet.When the public wants something different to look at.Round headlights are going back in cars,clothing of the seventies.......As far as loss of rudder grip when heeled over,you can deal with that.I would be more concerned of having the stern lifted up by a following sea.This can be very hard on the crew and potentialy dangerous.The majority of people want room first,How many people will it sleep? will be the first question.Having a big ass stern is brought to you by the people who put tailfins on cars.They sell right now.Try selling them 20 years from now, they will be outdated.A well designed boat may be old but is never outdated.
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Old 06-15-2005
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Fat Ass Sterns II

My experience sailing boats with fat ass sterns is limited to a few smaller cruiser/racers, but from what I can tell, they benefit more from being sailed upright than traditional designs, and they suffer more from heeling excessively than traditional designs. In other words, older designs are more forgiving of you if you sail them over-canvassed. Boats with fat ass sterns make you pay a greater penalty for making them labor, rail-down.

That means those who love to sail rail-down have to learn to sail them differently than they sail a traditional design. As the wind increases, you have to react promptly and appropriately to it by reducing sail area, keeping the boat upright. People who sail them that way love them, and say they sail very well and are quite safe and secure in a blow.
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Old 06-15-2005
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Fat Ass Sterns II

It seems to me that the fat ass sterns are another one of those design dejour ideas (see wing ding keels) coming from the racing circuit that was half ass applied to the production boat building business. Most of the "go around the world fast sleds" that have these FAS''s have twin rudders so that one of them IS in the water at all times.

For my money, I think I''ll stick with vessels that were designed to be sailed rather than house a small insurgency.
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Old 06-15-2005
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Fat Ass Sterns II

There seems to be a lot of discussion about why newer boats have wider sterns. There are a lot of reasons that modern boats tend to have wider sterns but increased accomodations is not necessarily one of them. More on that later. If we look a little bit of history, after the Fastnet disaster a lot of attention was focused on what makes a good seaworthy boat. Motion at sea became a popular research topic. Hull forms and weight distribution was studied in great detail. One of the trends that came out of all of that study was boats with longer waterlines and finer bows. Moving the waterline forward reduced pitching and making the bow finer reduced the impact with waves in a chop.

As bows became finer the center of bouyancy moved aft as well. At first this produced boats that developed a lot of weather helm as they heeled and which tended to jack their rudders out of the water and wipe out easily. As designers got better at modeling hull forms this became far less of a problem.

This combination of fine bow and powerful stern sections were found to offer exceptional upwind performance and reaching speeds that are substantially higher than theoretical hull speeds. So this fine bow, more powerful stern hull forms were really a win-win design trend that offered greater speed, coupled with better motion comfort and seaworthiness.

In a past issue of Sailing World there was an interesting couple paragraphs dealing with theoretical hull speed which touched on the issue of theoretical hull speed as it relates to these new hull forms. I am quoting here:

"Waterline''s affect on hull speed is theoretical and not absolute. As a hull goes faster, the bow wave stretches to the point where the bow and stern wave become on wave cycle, whose wavelength is equal to the waterline length. This brings us to wave theory. "

"The speed of a wave (in knots) is equal to the square root of the wavelength (in feet) multiplied by 1.34. If your boat has a waterline length of 32 feet, the theoretical hull speed is 7.6 knots. The waterline length is thought to limit the hull speed because if the boat goes any faster the stern waves has to move further back taking the trough between it and the bow wave along with it. As the trough moves aft, it causes the stern to drop, making the boat sail uphill."

"Except for planning designs, sailboats typically can''t generate enough power to go any faster and climb their own bow wave. But a boat with extra volume in the stern can exceed its theoretical hull speed because the extra bouyancy prevents the stern from dropping into the trough. By the same token, a fine-ended design might not achieve its theoretical hull speed if buoyancy in the stern is insufficient." (Written by Steve Killing and Doug Hunter).

That said, as with anything in yacht design all things need to be done in moderation and no matter how theoretically good any design idea might be, it can obviously be taken beyond a reasonable moderation to the point that it becomes a bad idea. Unfortunately from my perspective that is occurring in the case of many of the newer performance cruisers. If you look at the Volvo 60, IRC, or IMS race boat derived designs the transoms are not all that wide and the waterlines and flare are quite moderate. While these designs are fastest when sailed flat, they still are very easy to sail at reasonably large heel angles. Denr and I appear to be in agreement on the Open Class derived designs which tend to push transom widths to an extreme resulting in extremely large wetted surface, and poor handling without such remedial devices as trim daggerboards and dual rudder.

It is important to understand that it is much harder to design a good boat with a wide transom and fine bow than a more traditional hull form. These designs require more careful weight distribution and buoyancy distribution studies than more traditional designs. Sectional properties need to be more carefully configured as well. When done right, a properly designed fine bow, wider transom boat has no more tendancy to go down in the bow when heeled than a pinched stern boat (remember IOR boats had very pinched sterns and yet they were very prone to going bow down and wiping out with heel angle) and also has no more tendancy to wipe out.

But there is the rub. Proper design of fine bow, wide transom boats requires careful modeling at all heel angles and all pitch angles. It requires reasonable assumptions about loading and trim angles. Boats like the new Tartans seem to take on the wide transom look as a kind of fashion statement rather than as a carefully balanced design concept and as such seem to produce designs that are not all that great sailors in many of the repects mentioned above.

Beyond all of that, many new sailors seem to be unaware of the importance of weight distribution and trim angles. Traditional boats often carried 10% of their ballast as trim ballast that could be located as necessary to adjust the trim of the boat due to its state of loading. This is unheard of today. People tend to load boats almost haphazzardly thinking if the designer has created a locker then it is there to be filled with what ever fits regardless of its weight and position.

But all of that said, I do think that it is a bit of a stretch to say that these broader sterns solely resulted from trying to stuff in additional accommodations. I say this because as the stern gets broader, displacement is removed from the bow thereby reducing usable accomodations volume in the bow. If anything the accomodations are just shifted aft a bit. That is not necesarily a bad thing as the stern generally has less motion than the bow.


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Old 06-16-2005
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Fat Ass Sterns II

my girlfriend has a really fat ass stern and the ride she gives is excellent....especially in a blow
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Old 06-20-2005
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Fat Ass Sterns II

That comment was completely over the top and greatly appreciated.
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Old 06-20-2005
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Fat Ass Sterns II

It may be well to point out that a boat that is sailing rail down as it were is losing about twenty percent of the available power from the wind because the wind is washing over the sail not powering it.It looks neat to see a sailboat heeled over that much but you really can go faster with less heel
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