wave tub under 30k?

Discussion in 'Boat Design' started by billyc, Feb 26, 2009.

  1. pkoken
    Joined: Mar 2003
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    Location: Cruising Hawaii

    pkoken S/V Samadhi V

    billyc, if you wish to get help with your project I suggest you change your approach. Your posts so far sound like the work of a 10 year old.

    Designing boats is an activity best undertaken by adults. If you feel that shaping a board is like designing a boat, then I suggest you start out with a giant block of foam and bust out your planer and get to work.
     
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  2. billyc
    Joined: Feb 2009
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    Location: austin texas

    billyc ASCboards Shaper,Glasser

    adults? hahaaha more like haters

    Don't blame me for not knowing what's going on in the mainstream..I posted a credible post..got told to go on a cruise,try it behing a fishing trawler,spell check when calling apex a psycho,boat building is for adults,hahahaaha all negative,one liners trying to devalue my ideas.and you goons expect me to not defend myself? That will never happen ever! Its painfully clear you people have your heads so far up your pompass taylor the thaiylor arsses you will never have anything remotley credible for my thread..if you haters spent as much time helping as you try haten the boats would be that much better..instead,it is what it is..I've said all along,its all good,my ideas are in the werks already with the maxam teipei group in asia..hate on that."Wakes are bad in boating"hahahhahahahhaahahaa
     
  3. marshmat
    Joined: Apr 2005
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    Location: Ontario

    marshmat Senior Member

    Hi Billy,

    Let me start by saying that the answer to your initial post is on the front page of your sponsor's site:
    Most of what makes up the staggering price tag of a modern commercial wakeboard boat is "fluff". Carbon pinstripes, leather, polished stainless tower, anodized gauge bezels, gas-lift storage locker hatches, etc.

    If the wake is really all that matters, the solution is easy: you take the standard shallow-V tow boat hull that's been the norm for decades, you put a big honkin' V8 in it, and you bolt wedges, foils, etc. to the transom to suck it down. A simple but solid hull and an engine, plus a prop, rudder and a bunch of fittings, instruments, etc. and there you go, a 21-24 footer is certainly doable for less than $30k. But it won't look fancy, it won't have the features or the style of a Malibu, Tige, etc. It won't have a head, washdown shower, polished chromed tower, and all that jazz. It'll just be a hull, an engine, and a few seats- much like a workboat.

    If you think you can sell that, then more power to you. I'm not sure if you can, especially in the larger 24-28' size range you mention. Wakeboard culture isn't what it was in the '90s anymore; style means a lot to many potential buyers. And those who don't care about style tend to skip the showrooms and buy used ski boats to modify. And by the time you get to 28 feet, you're looking at something that's hard to trailer and getting expensive to run.

    As you're likely aware, wakeboarding is generally looked down on with disdain by the rest of the boating community. This isn't because people see it as a low-skill sport, or because other boaters hate wakeboarders in general. Rather, it's because a small percentage of wakeboarders tend to cause a great deal of trouble, buzzing back and forth close to the shoreline and through cramped channels, causing substantial damage to the shoreline, completely ignoring the COLREGS, and generally driving the neighbours insane.

    Nobody hates the boats, and nobody hates the people. But many of us are not impressed with the dangerous, destructive, illegal and annoying conduct of a very small, but very obvious, fraction of the wakeboarding community.

    It's also worth noting that the idea of designing a boat to intentionally create a very large wake is entirely new, and is restricted to this one small arena of boating. In absolutely every other aspect of boating, other than wakeboarding, the wake is a Very Bad Thing and enormous amounts of time and money are expended to find ways to minimize it.

    I hope that it is clear to you now why your posts have drawn the reaction you have seen. You are most welcome on this forum. But please keep in mind that, on boatdesign.net, higher standards of discussion are expected than in most of the 'Net. To be accepted on here, you must remain humble and keep an open mind. Personal insults, in particular, will draw sharp criticism and, if repeated, moderator intervention. Please take the time to re-read this entire thread. Think about what comments have drawn what reactions. Then keep the questions and ideas coming!
     
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  4. billyc
    Joined: Feb 2009
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    Location: austin texas

    billyc ASCboards Shaper,Glasser

    The current flagship in the wakesurf world is speced as follows
    420hp PCM motor/V drive/length24',7.32m/beam102",2.59"/draft30",.76m
    she weighs 4600lbs
    id like the beam and lenghth to stay the same but shape,draft,deadrise and hull design is what i would like to change.
    this boat comes stock with a left hand prop rotation which combined with 2000lbs in the port side rear locker makes a perfect 4'wave at 16mph without the switchblade.
    this boat when sacked out to the starboard side so goofy footed riders can face the wave doesnt make such a perfect wave.its big and ridable but washed out and nothing like the port side.
    this is an issue with all the wake boats today.
    hence the wave tub.
    how can i get it to werk on both sides without changing the prop rotation?
    the blade does allow for less ballast to make the wave and also helps in shaping it,
    but i was thinking it would be more efficient if the hull did most of the wave makin work.then add the sponsons,tabs,plows or blades to make it even better.
    the boston and blue whaler are high selling boats,they are set up the way im describing my wakesurf boat.stricktly buisiness,all function,hull,motor,bilge,ballast,stereo,wrap around bench seating all cnc'd out of a block of composit.
    yes it would have a work boat thing about it.
    but at $30k retail when the current comp is $95k
    as long as the wave is BIGGER it will sell.
    it could also make wakesurfing affordable to alot of people who might not of other wise been able to.
    i understand if know one here knows what im asking for,no problem,i thought it was just worth a try
    peace
     
  5. Mild Bill
    Joined: Nov 2007
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    Location: Northern Illinois

    Mild Bill Well, not entirely mild.

    Perhaps by using twin engines with opposite propeller rotations (if you can fit them within cost requirements).
     
  6. pkoken
    Joined: Mar 2003
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    Location: Cruising Hawaii

    pkoken S/V Samadhi V

    With a CPP and a transmission.
     
  7. billyc
    Joined: Feb 2009
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    Location: austin texas

    billyc ASCboards Shaper,Glasser

    tree shredder

    my folks have a 49' formula with twin counter rotating props.
    this set up is ok but not beginner ,user friendly at all.
    wave is great on the starboard side but washed out on the port side.
    plus its not very efficient.
    last summer i was surfing behind her,fell off the back of my surfboard,launched the board up under the swim platform between the screws,the channell created by the twin screws actually sucked the board in and shot out the destryed board like a giant tree shredder.
    imo this wave is fun but pro only.
    single engine with a channel down the center of the V hull to direct the thrust into a blade or trim tab might be good.
    i would say listing the boat over to the side of the boat surfing is just as important as displacement,
    ocean surfers surf a converging wave.
    wakesurfers are surfing a displaced wave.
    this is why i think a hull design is in order
    pkoken,forgive me,im just a lake wally..what is a CPP and a transmission?
     
  8. Mild Bill
    Joined: Nov 2007
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    Location: Northern Illinois

    Mild Bill Well, not entirely mild.

    I find this very interesting. Assuming that the propellers are geometrically the same except for the direction of rotation and each one is absorbing the same power at the same speed, there must be some other cause for the waves on each side to be significantly unequal.
     
  9. billyc
    Joined: Feb 2009
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    Location: austin texas

    billyc ASCboards Shaper,Glasser

    ha! now were talkin! mild bill your the man.
    exactly!
    thats why im here.
    ive wasted many hours of the day trying different trim tab combos.nuttin werkd.
    ive abandoned the whole yacht surfing deal until i can figure out whats going on with wakeboats 24' and under.
    that being said,there are some wakeboats in 21' to 22' range that will make a semi clean wave on both sides,but nothing like the huge wave on the 24'.
    but the 24' is finicky when trying to make a goofy side wave.
     
  10. Mild Bill
    Joined: Nov 2007
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    Location: Northern Illinois

    Mild Bill Well, not entirely mild.

    If the hull surface in contact with the water has an outward bulge on one side and an inward depression on the other side, the unequal lift could induce a rolling moment.

    I'm a lot more familiar with aerodynamics than hydrodynamics, so I'll note that on airplanes even a slight asymmetry which casual observers wouldn't particularly notice can have a large effect on both efficiency and behavior. One way of compensating for differential lift causing a rolling moment on an airplane is to hold the rudder (or set the rudder trim tab) to counteract the roll through dihedral effect. Performance suffers because the airplane isn't cleanly aligned with the relative wind, and this would include a wake that is not equal on each side.

    Just guessing here, but it seems to me a similar situation could obtain with an uneven hull bottom, at least on a hull with a significant amount of deadrise in contact with the water. Now, whether your boat has any asymmetry on the bottom and whether the effect from it would be large enough to cause such a great disparity in the waves on the sides, I'm not sure. Also, you've already played around with trim tabs, which I assume means tabs that trail off the bottom edge of the transom and can be adjusted differentially. That should be sufficient, but it may still be worthwhile to check the accuracy of the bottom surface the next time the boat is out of the water.

    The only other thing I can think of offhand is the symmetry of any corners that are in the water, e.g. chines, lift strakes, etc. If they're sharp on one side of the hull but rounded on the other you can get differential forces. Again, I'm not sure that that would be enough to account for the phenomenon you're observing.

    Time for the people who really know boat design to chime in.
     
  11. apex1

    apex1 Guest

    Look up, my answer is there.
    And my insight in aerodynamics may have some roots here:
    http://www.boatdesign.net/forums/at...n-i-make-gas-engine-run-wvo-richie_kanal7.jpg

    Regards
    Richard
     
  12. marshmat
    Joined: Apr 2005
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    Location: Ontario

    marshmat Senior Member

    Hi again Billy,

    CPP = controllable pitch propeller. Instead of being rigidly fixed to the hub, the blades are mounted on swivel fittings so you can change pitch on the fly. As seen on virtually all large prop-driven aircraft, and many commercial boats.

    I'm trying to figure out exactly what kind of wake profile you're after. It would be quite helpful if you could do a few sketches of the wake profile you want- roughly what shape you're trying to get, and where around the boat you're trying to get it. That would help to get everyone on the same page.

    The Formula 49 you mention is probably not designed with any inherent asymmetry, but there's still a variety of factors that could cause this. It may have a bit of a weight imbalance, or one side of the hull bottom might flex more than the other under load. Production builders sometimes tolerate quite a lot of variation from boat to boat, or even within one hull.

    For some reason, I'm starting to question whether the usual towboat approach of a fully-planing hull is really what you're looking for here. The commercial fishboat world has a few semi-displacement hull types that have evolved to pack as much weight as possible in a given length, and can be driven at 16+ mph (but will not plane, and will not go over 18-20 mph no matter what). I've seen a few that produce fairly high, smoothly rolling wakes when pushed hard. Not sure if this is what you're looking for, but it might be an interesting approach to explore for your application.
     
  13. billyc
    Joined: Feb 2009
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    Location: austin texas

    billyc ASCboards Shaper,Glasser

    wow! you guyz are blowing my mind,way more tech than i could have ever imagined.thank you

    in contest wakesurfing today we surf one side of the wake only because after ballasting 2000lbs in the rear locker and listing the boat over,the wakeboats wont allow the wave to be equal on both sides.

    a hull design that made an equal wave on both sides would change contest wakesurfing over night.thats how fledgling our new sport is.

    for now,a wake boat that makes a single wave on both sides would suffice.

    here is a video of one of my team riders surfing behind my contest boat.
    the wave is almost 4' tall,the pocket is like 25'back.im wanting a 5' or 6' tall wave with 50' of pocket.lol
    this should give you a good idea as to what im looking for.

    http://www.youtube.com/watch?v=7nE3E-gJVXM
     
    Last edited: Mar 4, 2009
  14. marshmat
    Joined: Apr 2005
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    Location: Ontario

    marshmat Senior Member

    Billy,

    What is the maximum speed you'd want this boat to go, period? Does it have to cruise at a decent clip when not being used to wakesurf?

    A 5-foot wave at 50 feet crest to crest, symmetrical and smoothly rolling without too much turbulence, could be easily generated with an adaptation of a harbour tug or high-volume "quota cheater" fishboat form. I think it should be possible to come up with a sort of semi-displacement hull shape that would produce a wake suitable for what you appear to be planning. It looks like you need a large riser with a smooth slope and high crest, that stays fairly close to the boat without causing too much disruption to the surroundings or forcing the surfer too close to the hull.

    But such a boat would be restricted to surfing speeds, and would not be able to kick up its heels and fly like a bat outta hell, as most planing-hull wakeboard boats can.
     

  15. billyc
    Joined: Feb 2009
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    Location: austin texas

    billyc ASCboards Shaper,Glasser

    if we could get her to go 22mph,she could fall in the wakeboat catagory.if not its still ok though
    wakeboarders go 22mph,wakeskaters go 21mph,wakesurfers go 9.5 to 16mph depending on what boat your in.
    i believe a wakesurfing specific boat would sell if it had a 5' wave. i could guarantee it would be used at the biggest wakesurf contests until a better wave is made.
    the wave is the main interface to our sport.
    surfers travel thousands of miles and spend thousands of dollars for a good wave.
    $30k to be the keeper of a 5' constant endless 16mph wave!
    i would purchase the first 3
     
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