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[PF Chesterfield]

Well, I am new on here, so a bit of background.

When I was young, my dad was in to model boating, he had a couple of kiln craft kits and such the like.  I joined in and got an MFA Pirhana for Christmas (probably 1986), and I had a couple of different cars too.  We used to go the club in Cwmbran (near where I grew up) most Sundays.

My Dad died when I was 13, and that's pretty much the last time I put a model boat in the water, although I did try and get back in to it a few times.  Now, fast forward 25 odd years, and I have a young daughter, a little bit of spare time and 4 model boats in the garage loft.  I reckon that the easiest and most fun one to get back and running would be the pirhana, and that could prove quite good fun for me and the little 'un.

So, a few questions regarding the Pirhana, that if anyone could help me with I would be most grateful.
- It has a 550 motor fitted, not water cooled, I seem to remember it going a storm with a 9.6v battery pack - but being a bit pedestrian with the 7.2v one from my car.  Am I best to stick with this motor and get an 8 cell pack to run it?  Or is there a better motor?
- ESC never existed when I last ran it (it had some sort of circuit board stuck to the top of the servo as speed control).  What sort of ESC should I go with and does it have to be water cooled?
- It has a plastic prop which I was told was inefficient, but I never got round to changing it, what sort of prop should I get?
- Finally if I fill some of the voids in the hull (ie. around the sides of the middle compartment) with this foam filler from an aerosol, would this make it less likely to sink?

Any help will be most appreciated.

Cheers

Philip


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[PF Chesterfield]

Sorry, keil kraft kits (Sea commander, Sea Cadet etc...), not kiln craft (think kiln craft made mugs......)

[Netleyned]

http://www.modelboatmayhem.co.uk/forum/index.php?topic=34333.0

Have a look at this rebuild.
If you're still in the Valleys
Cuppa is not far away

Ned

[Tug-Kenny RIP]

There's a few of us down Newport way.  Might see you at the lake. It's on Sunday morning 10 - 1,  And welcome to mayhem.

Keep them questions coming

regards

ken

[PF Chesterfield]

Thanks for the comments guys.  Should have made clear, I grew up in Caerleon and used to go to Cwmbran boating lake on a Sunday morning, but have since moved around quite a bit and currently live near Chesterfield, Derbyshire.

I have looked at the link thanks, so I should be looking for a 600 motor and running on it 7.4v Lipo's then?  I am not sure what a Lipo is, and how it differs from NiMH or NiCad?  Can I charge the LIPO with my regular charger?

I am also a bit unsure of how to fit the water cooling as my boat looks quite different inside to the ones in the photos.  Mine has quite a lot of ply inside and 2 bulkheads.

Cheers

[john s 2]

With your questions i wonder have you not read the section on batteries, charging etc? As for speed controllers this is well covered. If your existing motor gave you the speed you required then why change? I think you might have what is known as a Bobs boad ESC. John. 

[cuppa]

Thanks for the comments guys.  Should have made clear, I grew up in Caerleon and used to go to Cwmbran boating lake on a Sunday morning, but have since moved around quite a bit and currently live near Chesterfield, Derbyshire.

I have looked at the link thanks, so I should be looking for a 600 motor and running on it 7.4v Lipo's then?  I am not sure what a Lipo is, and how it differs from NiMH or NiCad?  Can I charge the LIPO with my regular charger?

I am also a bit unsure of how to fit the water cooling as my boat looks quite different inside to the ones in the photos.  Mine has quite a lot of ply inside and 2 bulkheads.

Cheers

Hi Sir

My Piranha runs very well on a speed 600 race motor powered by a 7.4v (2 cell) 5000mah lithium polymer pack. Lipo (lithium polymer) cells are different to nicads and nimh cells and need to be charged on a charger that is designed to charge Lipo cells. You will need to water-cool the motor - I burnt a speed 600 race motor out due to inadequate water cooling. 

Here is a link to some info on LiPo cells: http://www.electricwingman.com/guides/lithium-polymer-battery-guide.aspx

Cheers
          Jon (Cuppa)

[cuppa]

Sorry - forgot to mention.

The piranha I built is somewhat different to the 'kit standard' layout in that it uses a commercially available motor mount and I did not use the supplied plywood bulkhead. I also offset the battery pack to the left (as viewed from the back of the boat) to counter motor torque.

It is easy to install water-cooling - you can drill a hole in the plywood bulkhead to accommodate the necessary tubing. I made the mistake of locating the water pickup for the cooling as per the plan (directly behind the prop) and the water flow was insufficient. I have now removed the original pickup and am using a racing style pickup that is flush with the hull and about 3/4 inch on the right of the hull centreline - water flow is now very much improved.

The Piranha is a great fun sports boat and handles really well.