Piranha Housing and Battery swap

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rjack321

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lostsheep

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looks great

I'm guessing you are going to need lead in the nose and something to keep that battery in position

I erred on the high side of buoyancy for the tube so I have a lot to work with. If my math is right, I’ll need about 4 lbs. I have lots of front to rear adjustability and I can index to make the handle float up.

WRT the holder, I hear you and it is a concern. What is not obvious in the pictures is that the pieces are flared out by ~.050” at key locations so that once inserted in the tube the material is acting like a spring and wedging itself in place; creep is likely to be a problem.
 

rjack321

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I erred on the high side of buoyancy for the tube so I have a lot to work with. If my math is right, I’ll need about 4 lbs. I have lots of front to rear adjustability and I can index to make the handle float up.

WRT the holder, I hear you and it is a concern. What is not obvious in the pictures is that the pieces are flared out by ~.050” at key locations so that once inserted in the tube the material is acting like a spring and wedging itself in place; creep is likely to be a problem.
4lbs isnt bad! That gives you some leeway to put it for and aft for trim but not some crazy amount that makes you wish you bought a bigger battery.

Not sure if it helps but Genesis sticks some plastic tabs on the inside of his tubes with double sided tape. The battery latches in with little sideways rotating slips of aluminum. Not sure what kind of tape @Jon Nellis is using but maybe he'll share and you can make something similar. Since you don't need to remove your battery, you could also make something similar to your spud and mount your battery to that. Creep will definitely be an issue for bouncy boat rides if its standing vertical.
 
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lostsheep

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Update:

I finally got to take the big battery and housing out for a spin today. Pleased to report it didn't flood and for the most part performed well. After initial testing got it down to 120' and all is well.

I deliberately added about 1 lb less ballast than I thought I would need so it would float instead of sink. It was almost exactly 2 lbs light. What I didn't expect is that it was nose heavy. That's not a problem as I can shift the ballast rearward very easily; I thought for sure it would be the other direction.

Strangely enough, I did have another problem that was not related to the housing. The damn trigger got a mechanical obstruction, not sure if there's corrosion in the trigger rod or if sediment got in there but the throttle got stuck on and I had to fly it into the bottom.

The only scratch that hurts is the first one right?

64099483009__97A0C05D-D3B7-4D63-9271-0E1005DD6D01.jpg
 

FIGJAM007

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Well you can alway make another one! Well done. Maybe work on Delrin trigger rod. Saw a post on a Facebook group. Gets rid of possible corrosion issues
 

Jona Silverstein

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Nice work, but for future reference, if you feel like modifying it again, the pirahna and Cuda share the exact same tail section meaning the tubes are interchangeable...
 
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lostsheep

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Nice work, but for future reference, if you feel like modifying it again, the pirahna and Cuda share the exact same tail section meaning the tubes are interchangeable...

Good info.

Now to find a spare cuda body :wink:

Joking aside, have you put a Cuda body on a Piranha? If so, did you change the body to accommodate the piranha strap or did you modify the piranha tail to use the Nielsen latches? The cuda has 3 latches presumably 120 degrees apart; curious how others may have solved this.

I haven't measured but I am curious what changes diveXtras made between the sierra's sealing surfaces and the piranha / cuda surfaces and why. When I get a chance I'll try and measure and post actual numbers.

Related, why does the pre PTB piranha use a 262 O ring for the inner body seal vs the 261 for PTB piranhas and the cuda? Going back and forth seems odd.
 

Jona Silverstein

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The Sierra and cuda bodies are different diameters so they are not interchangeable. The Pirahna and cuda tails are the same. But the Pirahna has an extension welded to it.

As for the o-ring dilemma. Don’t know. If it fits and it seals, does it really matter?
 
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lostsheep

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The Sierra and cuda bodies are different diameters so they are not interchangeable. The Pirahna and cuda tails are the same. But the Pirahna has an extension welded to it.

As for the o-ring dilemma. Don’t know. If it fits and it seals, does it really matter?

Obviously and yes
 
https://www.shearwater.com/products/peregrine/

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