Step Bottom History
11-30-2002, 08:26 PM
#31
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For those inquiring minds on the OSO board who aren't familiar with the benefits of a stepped hull, what are they?
I personally have heard many pro's and con's.
What do y'all think?
Ricochet.
I personally have heard many pro's and con's.
What do y'all think?
Ricochet.
12-02-2002, 08:41 AM
#32
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The first steps were , in fact tried 70 years ago....and there is the rub. Steps work great.......................as long as that much of the bottom is in the water......so it is a question of speed. If you are dealing with a monohull, and a step is say 60" forward of the transom, then the step will break the running surface up and reduce friction..... if that much of the bottom is wet. The old boats pictured carried a lot of motor weight and ran very "wet" to begin with. That's why tunnel boats use them.....mostly in turns when the sponsons are sucked down...not in straight a ways.
If you can rock your vee back onto the last 12-18" of pad you are already going too fast for steps to give you a speed increase. That's why non-stepped Allisons are so competitive in outboard drag racing. However, in turns the monohulls lose rear end tractability with aerated (stepped) surfaces and either spin out or hook and barrel roll more frequently with all that junk on the bottom.
A cat tends to turn on the inside sponson walls and holds better in turns than a vee....but a non stepped cat will spin out less often then a stepped cat as well. It is not a question of absolutes but rather of degrees. My 28 Skater runs fastest when I am able to trim all of the steps out of the water, but before I gain too much attack angle and increase aerodynamic drag.
Mike, we did, in fact put steps on two 21 Shadows in 1981, a Sterndrive and an outboard, Both boats were identical grey, white and Navy blue and their photos graced our brochure that year. The steps were 1 and 1/2 " deep, and made the boats no faster....yet they were more slippery in turns. This is still true today.
As to the Wing Switzer, that design is not a true cat or tunnel but rather a four point HYDROPLANE. Hydros by design kiss off on the forward sponsons and carry the aft section completely clear of the water......and without skid fins they literally don't turn at all.
Sound familiar?
T2x
If you can rock your vee back onto the last 12-18" of pad you are already going too fast for steps to give you a speed increase. That's why non-stepped Allisons are so competitive in outboard drag racing. However, in turns the monohulls lose rear end tractability with aerated (stepped) surfaces and either spin out or hook and barrel roll more frequently with all that junk on the bottom.
A cat tends to turn on the inside sponson walls and holds better in turns than a vee....but a non stepped cat will spin out less often then a stepped cat as well. It is not a question of absolutes but rather of degrees. My 28 Skater runs fastest when I am able to trim all of the steps out of the water, but before I gain too much attack angle and increase aerodynamic drag.
Mike, we did, in fact put steps on two 21 Shadows in 1981, a Sterndrive and an outboard, Both boats were identical grey, white and Navy blue and their photos graced our brochure that year. The steps were 1 and 1/2 " deep, and made the boats no faster....yet they were more slippery in turns. This is still true today.
As to the Wing Switzer, that design is not a true cat or tunnel but rather a four point HYDROPLANE. Hydros by design kiss off on the forward sponsons and carry the aft section completely clear of the water......and without skid fins they literally don't turn at all.
Sound familiar?
T2x
Last edited by T2x; 12-02-2002 at 08:47 AM.
12-02-2002, 10:26 AM
#33
Rough Seas Lie Ahead
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T2x I always enjoy your inputs and calling the kettle black. I'm no engineer, but your explanation has been plain/obvious in my mind for quite sometime now. I too think buyer beware of the hype...
12-02-2002, 10:48 AM
#34
I love the pictures of RonP and the construction of the boats.
How about this thought, it (the steps) had nothing to do with speed but came to be because when building a wooden boat they didn't have any straight pieces of wood 30'+ long, so they had to overlap the wood planks only as a method of construction. That way they got the length and the strength that they needed. So with 12' lengths of wood and a 'step' or overlap every 6', they were able to build longer boats, even up to 50'. Only later did they find that the speed went up. Then with glasfiber, the construction method changed.
How about this thought, it (the steps) had nothing to do with speed but came to be because when building a wooden boat they didn't have any straight pieces of wood 30'+ long, so they had to overlap the wood planks only as a method of construction. That way they got the length and the strength that they needed. So with 12' lengths of wood and a 'step' or overlap every 6', they were able to build longer boats, even up to 50'. Only later did they find that the speed went up. Then with glasfiber, the construction method changed.
Last edited by cobra marty; 12-02-2002 at 10:58 AM.
12-02-2002, 11:29 AM
#36
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T2X
THE WAY YOU EXPLAIN EVERYTHING REMINDS ME OF SOMEONE ELSE. SOMEONE MIGHT GET THE WRONG IDEA AND THINK YOU JUST MIGHT KNOW WHAT YOU ARE TALKING ABOUT. IMAGINE THAT STEPS WERE AROUND 70+ YEARS AGO, GEE I REMEMBER SOMETHING LIKE UNLIMITED'S IN THE TWENTIES WITH STEPS, I THINK THAT HELPED THEM THOUGH I NOT QUITE SURE WHAT THEY DO FOR TODAY'S BOATS. UNLESS YOU JUST WANNA GO STRAIGHT AND NOT TURN. I KNOW THERE'S A WHAT? FOR EVERY SEAT.
THE WAY YOU EXPLAIN EVERYTHING REMINDS ME OF SOMEONE ELSE. SOMEONE MIGHT GET THE WRONG IDEA AND THINK YOU JUST MIGHT KNOW WHAT YOU ARE TALKING ABOUT. IMAGINE THAT STEPS WERE AROUND 70+ YEARS AGO, GEE I REMEMBER SOMETHING LIKE UNLIMITED'S IN THE TWENTIES WITH STEPS, I THINK THAT HELPED THEM THOUGH I NOT QUITE SURE WHAT THEY DO FOR TODAY'S BOATS. UNLESS YOU JUST WANNA GO STRAIGHT AND NOT TURN. I KNOW THERE'S A WHAT? FOR EVERY SEAT.
12-02-2002, 12:51 PM
#37
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Steps and the Pleasure Boater
Fountains sport cruiser has caught my fancy. 
I note a 5 mph increase in top end when they went to the stepped hull design. The same increase in top end occurs for other manufacturers models (Cig, Formula, etc.). For the average guy, is this not a good thing? I fully appreciate the dangers of a stepped hull boat hooking in a sharp turn, but I doubt I would lock the wheel at 70 mph regardless of hull design.
For the cautious pleasure boat buyer, aren't effectively engineered stepped hulls a good way to get that increase in speed we all crave?
[ OH NO - I've noticed the props on most 38 SC pics I've seen turn IN. That could be a problem...]
I note a 5 mph increase in top end when they went to the stepped hull design. The same increase in top end occurs for other manufacturers models (Cig, Formula, etc.). For the average guy, is this not a good thing? I fully appreciate the dangers of a stepped hull boat hooking in a sharp turn, but I doubt I would lock the wheel at 70 mph regardless of hull design.For the cautious pleasure boat buyer, aren't effectively engineered stepped hulls a good way to get that increase in speed we all crave?
[ OH NO - I've noticed the props on most 38 SC pics I've seen turn IN. That could be a problem...]
12-02-2002, 01:07 PM
#38
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TX2,
I agree with what you are saying about riding on the last 12-18". If the water was like glass then you could trim accourdingly. However, what happens when the boats bounce? Is speed lost with a conventional V?
By the way, your argument is exactly why Jay Ross at Sonic said he doesn't use Steps.
I agree with what you are saying about riding on the last 12-18". If the water was like glass then you could trim accourdingly. However, what happens when the boats bounce? Is speed lost with a conventional V?
By the way, your argument is exactly why Jay Ross at Sonic said he doesn't use Steps.
12-02-2002, 02:49 PM
#39
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I think that Frequency makes a good point. At 60 to 80 mph steps possibly could help a bit in a straight line(this is when a monohull is still relatively "wet"), but that still doesn't offset the loss of directional predictability in turns. Is it possible that a 60 mph boat could gain speed with a step....? Theoretically yes, but a 70 mph 21' Shadow......did not. Maybe it's a function of scale and a smaller boat has a lower speed threshold or range. Perhaps we should have tested the Shadows with 50 mph engine packages.
I personally would not sacrifice turning control for a fancy bottom and some theoretical speed increase. Especially when Sutphens, Apaches, Allisons and etc. all run just fine thank you.......without them.
T2x
I personally would not sacrifice turning control for a fancy bottom and some theoretical speed increase. Especially when Sutphens, Apaches, Allisons and etc. all run just fine thank you.......without them.
T2x
12-02-2002, 03:43 PM
#40
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Just my personal $.02
While I can appreciate the theory behind the stepped hull, aerating the water to reduce drag, I feel that the designs are starting to border on marketing-driven absurdity.
Has anybody seen the steps built into the Regal hull (not high-performance, I know, but to make my point)? They've got these huge notches, and curves, and swerves---it it reaching the point where, if a manufacturer (particularly high performance) does not incorporate steps into the design of their hull, everyone thinks they're behind the times, or clueless.
Admittedly, my offshore performance boat driving experience is limited to traditional V-hulls, so I am a bit biased, but I enjoy the predictability of a straight V, where I know I can trim in, throw the boat into a turn, and I know she'll carve without any crazy, unexpected spin-outs.
I had a close, personal friend get killed while test driving a brand-new 38' V hull performance boat (stepped hull). The boat was built by a very well known manufacturer, but the design was new to them. The boat apparently spun out.
My friend was a highly experienced driver, and was NEVER reckless.
That was several years ago, and my view on stepped hulls has been tainted ever since.
'Lotsa marketing, limited actual benefits.
While I can appreciate the theory behind the stepped hull, aerating the water to reduce drag, I feel that the designs are starting to border on marketing-driven absurdity.
Has anybody seen the steps built into the Regal hull (not high-performance, I know, but to make my point)? They've got these huge notches, and curves, and swerves---it it reaching the point where, if a manufacturer (particularly high performance) does not incorporate steps into the design of their hull, everyone thinks they're behind the times, or clueless.
Admittedly, my offshore performance boat driving experience is limited to traditional V-hulls, so I am a bit biased, but I enjoy the predictability of a straight V, where I know I can trim in, throw the boat into a turn, and I know she'll carve without any crazy, unexpected spin-outs.
I had a close, personal friend get killed while test driving a brand-new 38' V hull performance boat (stepped hull). The boat was built by a very well known manufacturer, but the design was new to them. The boat apparently spun out.
My friend was a highly experienced driver, and was NEVER reckless.
That was several years ago, and my view on stepped hulls has been tainted ever since.
'Lotsa marketing, limited actual benefits.
