came accross these newly designed ....
03-24-2004 | 02:20 PM
#12
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some older stepped boat designs...fyi
Stepped Hulls
The concept was originally proposed by Rev. Ramus of Sussex England in 1872. He proposed both a single stop with tandem planing surfaces, and a combination of three pontoons with one forward and two aft. Indications are that these shapes were derived from model tests. Unfortunately, the heavy steam power plants of that day could not push a hull fast enough to plane, and take advantage of the new concept.
As early as 1906 there were published drawings for small stepped hulls with hard chines. William Henry Fauber [8] obtained a U.S. patent for hulls with multiple steps in 1908, but could find few people in the U.S.A. interested, so he moved to Europe.
Two small boats Solair (12') and Flapper (15') demonstrated the potential of stepped hulls as did the Harmsworth challenger Pioneer (5 steps) in 1910. (See Data Chart, Figure 12.)
The stepped hull began practical development about at the same time as the hard chined planing hull. A step in the bottom of a hull, raises part of the bottom surface so that it is no longer touching the water. Less wetted area. At the same time, the planing surfaces meet the water at a near optimum angle of attack over a wide range of speeds. The stepped hull is very efficient hydrodynamically.
Figure 9. Planing Hulls - Hard Chine
Refer to Figure 9 : Sketch of Hard Chined Planing Hulls
In the early days of stepped hulls, it was not certain just how many steps should be incorporated. Pioneer had 5 steps in 1910. Maple Leaf IV had 5 steps.
Maple Leaf IV: Length 39'-11' x Beam 8' . Two V-8 engines 350 Hp. each.
In 1912, Maple Leaf IV came over, from England, won the Harmsworth Trophy, and took it home. She had no less than five steps, and the driver sat on a pedestal high above the transom in order to see over the bow.
Some hulls had so many steps that they were called "shingled'. Rainbow IV (12 steps);
Eventually, model tests showed that a single step would be most efficient if you could locate it in the right position and give.it the proper depth.
Stepped Hulls
The concept was originally proposed by Rev. Ramus of Sussex England in 1872. He proposed both a single stop with tandem planing surfaces, and a combination of three pontoons with one forward and two aft. Indications are that these shapes were derived from model tests. Unfortunately, the heavy steam power plants of that day could not push a hull fast enough to plane, and take advantage of the new concept.
As early as 1906 there were published drawings for small stepped hulls with hard chines. William Henry Fauber [8] obtained a U.S. patent for hulls with multiple steps in 1908, but could find few people in the U.S.A. interested, so he moved to Europe.
Two small boats Solair (12') and Flapper (15') demonstrated the potential of stepped hulls as did the Harmsworth challenger Pioneer (5 steps) in 1910. (See Data Chart, Figure 12.)
The stepped hull began practical development about at the same time as the hard chined planing hull. A step in the bottom of a hull, raises part of the bottom surface so that it is no longer touching the water. Less wetted area. At the same time, the planing surfaces meet the water at a near optimum angle of attack over a wide range of speeds. The stepped hull is very efficient hydrodynamically.
Figure 9. Planing Hulls - Hard Chine
Refer to Figure 9 : Sketch of Hard Chined Planing Hulls
In the early days of stepped hulls, it was not certain just how many steps should be incorporated. Pioneer had 5 steps in 1910. Maple Leaf IV had 5 steps.
Maple Leaf IV: Length 39'-11' x Beam 8' . Two V-8 engines 350 Hp. each.
In 1912, Maple Leaf IV came over, from England, won the Harmsworth Trophy, and took it home. She had no less than five steps, and the driver sat on a pedestal high above the transom in order to see over the bow.
Some hulls had so many steps that they were called "shingled'. Rainbow IV (12 steps);
Eventually, model tests showed that a single step would be most efficient if you could locate it in the right position and give.it the proper depth.
03-24-2004 | 02:25 PM
#13
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http://www.aeromarineresearch.com/tbdp6.html
.if you are designing a boat or want to do more with designs in theory or practice this site offers software to get you going ...really neat software!
.if you are designing a boat or want to do more with designs in theory or practice this site offers software to get you going ...really neat software!
Last edited by LPA2106; 03-24-2004 at 02:30 PM.
03-24-2004 | 02:48 PM
#14
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....hope this is interesting ...sorry for all the posts..but figured if anyone was interested they might like to review this...I talked to a manufacturer's rep. who agreed with "Downtown42's" friend's assessment..that triple engines are harder to spin out vs. twins in a relatively longer stepped boat....so a 47' stepped with triples is harder to spin than twins..this guy agreed...triple offer more prop bite....so a heavilly cupped prop deep enough in the water helps...x-dimension is really really important....I guess surface props and steps at high speeds may be a handful?
....so if speed is not a factor than a heavier non-stepped hull is for you...like an older Apache, Cig, Scarab,Formula..and of course some of the current non-stepped Pantera's...
..any opinions if one company has "safer step designs" than others?
....so if speed is not a factor than a heavier non-stepped hull is for you...like an older Apache, Cig, Scarab,Formula..and of course some of the current non-stepped Pantera's...
..any opinions if one company has "safer step designs" than others?
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