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Seakeeper + Contender

Old 09-13-2018, 08:05 AM
  #121  
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Originally Posted by FishHarder View Post


Guys are thinking of the forces wrong. Those of us remember playing with hand held gyros..when your hand was steady...there was no force..when you rotated your hand around..the force came into play...same with seakeeper..when it is allowed to rotate it creates a counter acting force..Seakeeper also has computer aided rotation that most efficiently counter acts the boats movement. Other wise you might need a seakeeper twice the size.

Now how about two gyro's one eliminating side to side roll, the other eliminating front to back roll. It would be like a hover craft?
Not a counter acting force. It's a translated force acting 90 out of phase in advance of the rotation.

No need for two..... just need to rotate the same one in a different axis.
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Old 09-13-2018, 08:07 AM
  #122  
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Originally Posted by catch up View Post
But not all step hulls are prone to lose control when subjected to a high speed turn. I know of several builders that designed and tested their hulls for this very thing, knowing that while steps can have benefits they can also have handling issues in certain conditions if not executed properly. Maybe that had nothing to do with this particular boat but it has happened to this model from this same builder in other instances.

Would it matter if a hull has two steps like this contender or a single step like Intrepid?

I recall watching something on YouTube that showed SeaVee spent extra time designing their stepped hull because of the problems they encountered while testing (spinning out)
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Old 09-13-2018, 08:08 AM
  #123  
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Many of y'all need to go grab your tween kid's fidget spinner that he/she isn't using anymore; and feel the physics for yourself!
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Old 09-13-2018, 08:20 AM
  #124  
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Traditionally in a non-step v-bottom you would trim down to plant the bow to turn at speed. Stepped bottom you need to keep the stern planted to avoid rotating on the forward step. Not as much a design flaw as operator error. Not sure how a Seakeeeper responds to these forces. Is this what happened?
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Old 09-13-2018, 09:08 AM
  #125  
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Originally Posted by MUHSFINK07 View Post
Would it matter if a hull has two steps like this contender or a single step like Intrepid?

I recall watching something on YouTube that showed SeaVee spent extra time designing their stepped hull because of the problems they encountered while testing (spinning out)
I asked the guys at Intrepid why they didn't go to twin steps, the response was "we are not building race boats and prefer predictable handling". Honestly, I don't want my fishing cruiser to handle like my Cigarette and adding one more step is just going to make it looser in the ass with maybe a little more top end. The second step probably doesn't gain any efficiency over a single step at normal operating speeds.
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Old 09-13-2018, 09:26 AM
  #126  
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Originally Posted by WildHawk View Post
I asked the guys at Intrepid why they didn't go to twin steps, the response was "we are not building race boats and prefer predictable handling". Honestly, I don't want my fishing cruiser to handle like my Cigarette and adding one more step is just going to make it looser in the ass with maybe a little more top end. The second step probably doesn't gain any efficiency over a single step at normal operating speeds.
Well thats a great answer. Thank you! Can't wait to see yours and get some numbers off of her!
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Old 09-13-2018, 10:02 AM
  #127  
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Those in the know let me know if this is correct.

Let's think of a boat as a see-saw. Seakeeper is in the middle at the pivot point. SK in "unlocked" position means the gyro is free to move. When the front of the see-saw moves up the gyro moves back (opposite direction) to counteract the force. When the SK is "locked" the gyro cannot move. Front of the see-saw goes up and SK has no effect. It is still connected to the see-saw, but because the gyro does not move inside the casing it moves with the see-saw instead of counter-acting the see-saw's movement.
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Old 09-13-2018, 10:12 AM
  #128  
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Originally Posted by Locke N Load View Post
Those in the know let me know if this is correct.

Let's think of a boat as a see-saw. Seakeeper is in the middle at the pivot point. SK in "unlocked" position means the gyro is free to move. When the front of the see-saw moves up the gyro moves back (opposite direction) to counteract the force. When the SK is "locked" the gyro cannot move. Front of the see-saw goes up and SK has no effect. It is still connected to the see-saw, but because the gyro does not move inside the casing it moves with the see-saw instead of counter-acting the see-saw's movement.
Yes, that's how it works per SeaKeeper.
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Old 09-13-2018, 10:30 AM
  #129  
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Originally Posted by bjm9818 View Post
Gerald

when you were installing the unit, was there any mention about effectiveness vs location? It’s been 20 years since my engineering Mechanics class on forces but I would assume if you could attach it on the stringers it would be more effective vs deck level?

i wonder how a fiberglass boat reacts
The one I installed was on a fiberglass boat, 40 years old, worked all his life, plywood deck with structural beams laminated from construction grade 2 x 4s...
I don't remember all the logistics of the mounting location, my client came to me with a problem ( he wanted a gyro installed ), I did some research as to the flexibility of the installation, proposed the location and then we hired a naval architect for the back-and-forth with Sea keeper. We ended up installing a larger gyro then what Sea keeper promoted in their literature but they turned the RPM down because this was the highest duty cycle installation to date.

Originally Posted by Locke N Load View Post
Those in the know let me know if this is correct.

Let's think of a boat as a see-saw. Seakeeper is in the middle at the pivot point. SK in "unlocked" position means the gyro is free to move. When the front of the see-saw moves up the gyro moves back (opposite direction) to counteract the force. When the SK is "locked" the gyro cannot move. Front of the see-saw goes up and SK has no effect. It is still connected to the see-saw, but because the gyro does not move inside the casing it moves with the see-saw instead of counter-acting the see-saw's movement.
No in that the force of the gyro is 90° to the axis that it is swinging on, look at the photo that I previously posted, the gyro is rocking fore an aft and exerting its energy port to starboard.
Gerald
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Old 09-13-2018, 10:44 AM
  #130  
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Default ...the concrete wall...

Originally Posted by Anthem View Post
Not sure you can mitigate turning hard right/left in a step hull when in WOT (or close to it) no matter what manufacturer you are.

Or even the hull form. Several people have already posted the idea. But the boating world in many ways mimics the auto world. Fifteen years ago who would have heard of a 300 hp toyota Camry or a 700 hp 'Hellcat'?



Earlier this year I walked into Grove Key Marina's barn and was amazed to see nothing but trips and quads on the racks...


Water (in liquid form) has a way of turning into a solid by merely increasing the speed at which you travel on it. At 60 or 70 mph, imagine all those 'little' 2 to 3 foot concrete walls...and hitting them at anything but head on...


The skipper on the Contender will forever relive the day and wonder, what could he have done different. At least he has lived and may one day... 'tell the tale' -
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Old 09-15-2018, 06:02 PM
  #131  
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Originally Posted by Locke N Load View Post
Those in the know let me know if this is correct.

Let's think of a boat as a see-saw. Seakeeper is in the middle at the pivot point. SK in "unlocked" position means the gyro is free to move. When the front of the see-saw moves up the gyro moves back (opposite direction) to counteract the force. When the SK is "locked" the gyro cannot move. Front of the see-saw goes up and SK has no effect. It is still connected to the see-saw, but because the gyro does not move inside the casing it moves with the see-saw instead of counter-acting the see-saw's movement.
Not exactly, the seakeeper is only countering roll not pitch and is usually located well aft of the center of gravity in the installations I have seen.
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Old 09-16-2018, 10:14 AM
  #132  
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We will never know The Hull Truth of this hull.
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Old 09-17-2018, 03:42 AM
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I always figured "Seakeeper" was a gimmick to comfort newbies and their wives.
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Old 09-17-2018, 08:23 AM
  #134  
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Originally Posted by kylewalker View Post
I always figured "Seakeeper" was a gimmick to comfort newbies and their wives.
I disagree and you haven't been around one that was working.
Gerald
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Old 09-17-2018, 08:30 AM
  #135  
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Originally Posted by kylewalker View Post
I always figured "Seakeeper" was a gimmick to comfort newbies and their wives.
If I had enough cash to burn I would buy one. Maybe one day they will become a little more reasonable on price. Would certainly make bottom fishing or trolling in the slop more comfortable.
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Old 09-17-2018, 08:39 AM
  #136  
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Originally Posted by lurker25 View Post


If I had enough cash to burn I would buy one. Maybe one day they will become a little more reasonable on price. Would certainly make bottom fishing or trolling in the slop more comfortable.
The smaller ones are becoming more affordable. No different than the cost of a motor on the back of a boat what would fit one. The Seakeeper 2 costs $22,000 and works on a 27-35' boat. A 300hp outboard is $25k and boats in this class usually have 2......
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Old 09-17-2018, 09:18 AM
  #137  
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The question is how long till we see a seakeeper on a bay boat
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Old 09-17-2018, 09:37 AM
  #138  
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Originally Posted by Leeroyjenkins View Post
The smaller ones are becoming more affordable. No different than the cost of a motor on the back of a boat what would fit one. The Seakeeper 2 costs $22,000 and works on a 27-35' boat. A 300hp outboard is $25k and boats in this class usually have 2......
But then there's also the cost of installation which can be considerable.
In late 2014, Sea keeper was able to reduce their cost considerably and it was then that my client was able to consider one. From their catalog, the one that appeared to be suitable for our installation was somewhere just shy of $90,000 plus installation. Because of the high duty cycle ( this was the first installation on an offshore boat that worked for a living, there were some on work boats but not boats that were offshore as great of a percentage of time ) Sea keeper opted to sell us the next size larger ( listed at near 150,000 ) four somewhere near 90 ( I wasn't paying the bills ) but my cost for installing the unit was substantial and we had a naval architect involved as well.
For anybody thinking about retrofitting one of these, installation cost will be substantial.
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Old 09-17-2018, 10:07 AM
  #139  
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Well, I loaded those incorrectly but if you have any interest you can figure it out. Previously in this thread I posted a photo of it in operation.
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