Step Bottom History
12-02-2002, 10:35 PM
#51
Allergic to Nonsense
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Speaking of steps...Shockwave has a few of them...new design...and still gets stuck to the water....
Who said that?......there he goes......... I got him by the hair....nope, he escaped...all I have is this dreadful little furry thing.
T2x...past my bedtime
Who said that?......there he goes......... I got him by the hair....nope, he escaped...all I have is this dreadful little furry thing.
T2x...past my bedtime
12-02-2002, 11:16 PM
#52
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Steve 1 is right, most steps are poorly designed. When I look at the steps in my boat and those on some of the others I wonder if they heard of a wind tunnel much less tested in one.
From Ocke Mannerfelt:
Most of the stepped hulls currently in production were originally designed as non-stepped V-hulls. Steps have often been added to these original designs as an afterthought, and then built into existing molds. This is not the case with the B-28. From the very beginning, the B-28's transverse steps were engineered as an integral part of the boats running surface and have been strategically placed to serve specific purposes and provide excellent balance. The first step sets the angle of attack of the hull, while the second step controls the waterflow to the aft section of the hull, which carries most of the boats load. The steps are also carefully shaped to introduce air into the water under the boat. The resulting air bubbles act as ball bearings, providing a faster, less resistant running surface. Planing over a bed of foaming water reduces friction, increases speed, and benefits fuel economy.
From Ocke Mannerfelt:
Most of the stepped hulls currently in production were originally designed as non-stepped V-hulls. Steps have often been added to these original designs as an afterthought, and then built into existing molds. This is not the case with the B-28. From the very beginning, the B-28's transverse steps were engineered as an integral part of the boats running surface and have been strategically placed to serve specific purposes and provide excellent balance. The first step sets the angle of attack of the hull, while the second step controls the waterflow to the aft section of the hull, which carries most of the boats load. The steps are also carefully shaped to introduce air into the water under the boat. The resulting air bubbles act as ball bearings, providing a faster, less resistant running surface. Planing over a bed of foaming water reduces friction, increases speed, and benefits fuel economy.
12-03-2002, 02:49 AM
#53
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Steps or notches?
I think many of you are talking about notches in an otherwise straight bottom and calling them steps. In the attached picture notice that the steps change much like steps leading up a flight of stairs.
I disagree with the idea that steps only work on 30'+ boats. Although there are also other reasons my 22'8" boat runs so extremely well in rough or calm water (wings, straight strakes, speed rails, aerodynamic and hydrodynamic design), I doubt Ocke put the steps in because of his marketing department. I had and have seen many boats running on the last 18" and although they are fast they are on the edge of out of control and you can forget staying that way in rough water.
My boat runs 100 at the same angle of attack as at 70, calm or rough water, so I don't understand how the conclusion can be drawn that you have to go under 70 to make steps work. Maybe some time in a wind tunnel would help in finding the right placement, height, etc. to get it right.
Lets stop comparing bad steps that probably were designed by the marketing department or someone who did not fully design them, and consider do well designed steps make a difference. I believe yes and until I see a 23 ft. non-step boat that runs with mine in the sea or the wind tunnel I will rest my case.
I disagree with the idea that steps only work on 30'+ boats. Although there are also other reasons my 22'8" boat runs so extremely well in rough or calm water (wings, straight strakes, speed rails, aerodynamic and hydrodynamic design), I doubt Ocke put the steps in because of his marketing department. I had and have seen many boats running on the last 18" and although they are fast they are on the edge of out of control and you can forget staying that way in rough water.
My boat runs 100 at the same angle of attack as at 70, calm or rough water, so I don't understand how the conclusion can be drawn that you have to go under 70 to make steps work. Maybe some time in a wind tunnel would help in finding the right placement, height, etc. to get it right.
Lets stop comparing bad steps that probably were designed by the marketing department or someone who did not fully design them, and consider do well designed steps make a difference. I believe yes and until I see a 23 ft. non-step boat that runs with mine in the sea or the wind tunnel I will rest my case.
12-03-2002, 08:30 AM
#55
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Drawing on my vast offshore experience, gained simply by reading posts on this forum
, I too have concluded that longer, heavier boats gain the most from steps. The cool marketing photos of boats running "aired out" clearly show the steps, but the steps are ineffective at this point. Heavier boats will be running on the steps and benefit from air introduction.
In the case of smaller/lighter boats, to some extent I think speed gains were made in stepped-version hulls by accident. The result of a stepped bottom hull is a shorter transom. With a shorter transom the outdrives are better able to leverage the hull out of the water, resulting in greater speed. Anyone agree?
, I too have concluded that longer, heavier boats gain the most from steps. The cool marketing photos of boats running "aired out" clearly show the steps, but the steps are ineffective at this point. Heavier boats will be running on the steps and benefit from air introduction.In the case of smaller/lighter boats, to some extent I think speed gains were made in stepped-version hulls by accident. The result of a stepped bottom hull is a shorter transom. With a shorter transom the outdrives are better able to leverage the hull out of the water, resulting in greater speed. Anyone agree?
12-03-2002, 09:12 AM
#56
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In the case of smaller/lighter boats, to some extent I think speed gains were made in stepped-version hulls by accident.
I would much rather be in the water with control and efficiency than loose on the last 18 inches of the boat.
12-03-2002, 10:19 AM
#57
Rough Seas Lie Ahead
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...... after all it's not what you can actually deliver but rather what your marketing guys say you can do...in today's "business plan" environment....or to put it more succinctly if you spend enough on ads your boat will get a LOT faster.
T2x once again well said as usual. Obviously those who put so much pride into their ownership of the "over-rated" step concept in performance pleasure boats are gonna be in denial until the cows come home. I think the comment addressing putting a step on an already existing V design says a lot too...
Tom, though I believe with the Bat boat design the step probably does the trick in that configuration with wind tunnel testing etc. I don't however believe we're gonna see that design become the rage of the pleasure performance boat genre anytime soon due to it's impracticality and basic ugliness.
T2x made another realistic point when addressing the well intended but badly thought over comparison between a Sonic and the AT. You would be essentially saying without the steps they would run identical? As well as other similar sized stepped boats? They would all run identical? Or is there other differences to be thrown into the equation?...hmmmmmm
Another point of contention is in the rough stuff. It's hard for me to realistically imagine the benefits when the trim angles, tab settings, and horizontal/vertical g-forces are so consistently askew. Also theoretically speaking, you would have to believe with a little chop the V hull becomes just as aerated (okay maybe a tad less) as a stepped hull? Don't V hulls tend to run a little better on a lightly wind-chopped surface?...
Anyway, I guess one could sum it up by saying the differences between the two Corvettes is one is silver with cloth seats and the other is red with leather. I guess red with leather looks, seems, and is almost universally thought of as being.....faster?
T2x once again well said as usual. Obviously those who put so much pride into their ownership of the "over-rated" step concept in performance pleasure boats are gonna be in denial until the cows come home. I think the comment addressing putting a step on an already existing V design says a lot too...
Tom, though I believe with the Bat boat design the step probably does the trick in that configuration with wind tunnel testing etc. I don't however believe we're gonna see that design become the rage of the pleasure performance boat genre anytime soon due to it's impracticality and basic ugliness.
T2x made another realistic point when addressing the well intended but badly thought over comparison between a Sonic and the AT. You would be essentially saying without the steps they would run identical? As well as other similar sized stepped boats? They would all run identical? Or is there other differences to be thrown into the equation?...hmmmmmm
Another point of contention is in the rough stuff. It's hard for me to realistically imagine the benefits when the trim angles, tab settings, and horizontal/vertical g-forces are so consistently askew. Also theoretically speaking, you would have to believe with a little chop the V hull becomes just as aerated (okay maybe a tad less) as a stepped hull? Don't V hulls tend to run a little better on a lightly wind-chopped surface?...
Anyway, I guess one could sum it up by saying the differences between the two Corvettes is one is silver with cloth seats and the other is red with leather. I guess red with leather looks, seems, and is almost universally thought of as being.....faster?
Last edited by Reckless32; 12-03-2002 at 10:22 AM.
12-03-2002, 02:29 PM
#58
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Stepped bottom
I don't know what year or what brand this is, but it's got to be in the 20's, sitting at our lake waiting for it's turn in the restoration shop, kinda cool though.
