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Old Feb 24, 2009, 12:35 PM
Boaters are nice people.
Sneek, Netherlands.
Joined May 2004
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Mini-HowTo
Floodchamber: how to.

As the selfrighting option seems to pop up frequently, this may come in handy.
Mind you, this is how I do it, there are more ways to skin a cat...

How big should my floodchamber be?

Put all the goodies in the boat (as if you were going to run it), tape it shut and put it upside down in the water.
Most boats float upside down disturbingly stable…

Tape weight on the left side of the hull (port), until the hull will start to turn back up.

That weight, plus 10% to be sure, is the volume of your floodchamber.
A floodchamber wall usually runs along the edge of the hatch, slightly tucked under it to have room to epoxy it in place, from the transom to the front, where it meets the curve of the bow.

Take in account the room, necessary for your batterypack, as it will usually sit between the propshaft and the floodchamber wall.
Adapt the floodchamber wall if necessary to enable the Lipo pack (or NiMh pack) to lay flat on the bottom, to keep the CoG as low as possible.


Floodchamber wall.

I make a thin sheet of epoxy/glasscloth between two pieces of glass, covered in clingfilm to prevent the resin to stick to the glass.
Waxing the surface will do, but clingfilm is quicker.
Also anything with a smooth surface will do, I just happened to have a few pieces of glass at hand.

The sheet I make has roughtly the shape of the floodchamber wall, so having a card template of it helps determen the size.

As I build competition boats, weight is an issue, so the sheet is very thin, usually two/three layers of glasscloth (160gr).
Once the glasscloth and resin is in place I cover it with the second piece of glass and put some weight on it, squeezing the excess resin out.

When it has cured (24h epoxy), I peel it from the glass sheet and use the template to cut it to fit in the hull.
The epoxy sheet is paperthin and not yet watertight, that we’ll fix later.

Make sure the wall fits into the hull without any pressure, in order to avoid deforming the hull in any way.
Small gaps are ok.

Now for the clever part:

When a floodchamber runs along the entire length of the hull, it’s a RPITA to reach into the bow section to laminate in small strips of glasscloth to seal off the floodchamber.

Here’s my solution:

When the floodchamber wall fits, I laminate an extra layer of glasscloth onto the wall, leaving an overlap of half an inch all around.
Make sure the resin is applied very thin and tap the glasscloth onto the wall, so the overlap stays clear of the resin.

After it has cured, I cut the overlap to the desired size.

Position the wall into the hull (the overlap will close the small gaps) and laminate the overlap onto the hull with 24h epoxy, using a long thin brush to reach the bow section. Let it cure.

Cut out the transom and pour resin into the floodchamber, turning the hull so it runs into every corner, let it cure and fill the floodchamber with water to check for leaks.
Repeat the resin pour if there are any (after drying it out ofcourse).

Drill some holes into the deck to let the air out / water in, in case of a flip.

Ready.

It sounds very eleborate, but the actual installing of the wall only took me 20 minutes.

Original idea from Holgi, Germany.

Regards, Jan.
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Old Feb 25, 2009, 07:08 AM
Is life for real?
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Almere The Netherlands
Joined Sep 2006
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Hoi Jan, got any practical pics to show us, I´m quite curious and interested to know! Inquisitive minds weet je! Eus
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Old Feb 25, 2009, 08:58 AM
Boaters are nice people.
Sneek, Netherlands.
Joined May 2004
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Hi Eugene,

Pictures of the process, no, but I have a few of the floodchamber wall in position, I'll look into it tonight.

Regards, Jan.
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Old Feb 25, 2009, 07:47 PM
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Quote:
Originally Posted by pompebled
Hi Eugene,

Pictures of the process, no, but I have a few of the floodchamber wall in position, I'll look into it tonight.

Regards, Jan.
me too .sound very interesting to install a flood chamber.i going to installone in my arpro. a picture better than thousand words.

thankyou for the help .
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Old Feb 26, 2009, 03:11 AM
A piece of sublime engineering
Malaysia
Joined Nov 2008
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Quote:
Originally Posted by pompebled

...Drill some holes into the deck to let the air out / water in, in case of a flip.
Thousands words or pictures ... advice and tips from you is highly appreciated. Thanks Jan.
So.. normally, how big the holes u drill into the deck? And usually, how long does it takes for the hull to be self-right?
And does this mean that after the floodchamber fill with water, your boat will run with unbalance weight? How's this extra weight effected the "post" flip running?

-z9-
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Old Feb 27, 2009, 06:39 AM
Boaters are nice people.
Sneek, Netherlands.
Joined May 2004
4,986 Posts
Hi Zypher9,

As having holes in the boat is usually a thing to avoid, I try to keep them as small as possible, so nothing will get stuck in them (like another boat on a colission course).
I usually have a few pinholes at the bow end of the floodchamber to let the last air out of the chamber, particular important if the floodchamber is just big enough to make the boat flip back.

For my competition boats, recovery after a flip must be as quick as possible, so the floodchambers are as large as the hull in question allows and the holes are wide, to allow the water to rush in fast.
Usually they flip back in a matter of seconds, is nothing has gotten dislocated during the crash.

A boat with a floodchamber will sink in deep at the floodchamber side, when the boat starts to move, the water rushes out the back and the boat has it's normal riding attitude.
As I balance my boats to be heavier on the left, to counteract proptorque and the floodchamber is on that side too, the boats sit very deep on the rear left.
Not taping off the hatch isn't an option...

Regards, Jan.
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Old Feb 27, 2009, 10:39 AM
A piece of sublime engineering
Malaysia
Joined Nov 2008
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Thanks.. now everything make sense.
Regards,
-z9-
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Old Feb 27, 2009, 01:53 PM
Boaters are nice people.
Sneek, Netherlands.
Joined May 2004
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Pics added to O.P.

Regards, Jan.
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Old Mar 01, 2009, 03:36 AM
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Almere The Netherlands
Joined Sep 2006
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Jan, thanx as always very duidelijk Eugène
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Old Mar 01, 2009, 09:45 PM
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thank you .for yr helpful picture .now i got idea how to do on my arpro
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Old Mar 02, 2009, 01:40 AM
Boaters are nice people.
Sneek, Netherlands.
Joined May 2004
4,986 Posts
Quote:
Originally Posted by 2SPEAKER
thank you .for yr helpful picture .now i got idea how to do on my arpro
I found a picture of the Arpro, roughly outlining the floodchamber, on my harddisk, it's added to the O.P.

Regards, Jan.
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Old Apr 20, 2009, 08:56 PM
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Good info thanks Jan!
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Old Sep 02, 2014, 01:27 PM
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Has anyone tried this on a catamaran? I would think it would work the same but wanted to see if its possible before I wrecked a boat.
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Old Sep 02, 2014, 03:48 PM
Boaters are nice people.
Sneek, Netherlands.
Joined May 2004
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Hi slvrsky07,

I have seen working floodchambers on hydroplanes (pickleforks and roundnoses), but these didn't flip back up after a flip like a monohull, but started to float with the side of the floodchamber submerged, so the boat was on it's side, with the rear end further under water due to the weight distribution in the hull.

You needed radio contact, so you could throttle up the motor to get the boat to get back to the surface running with the right side up.

As this was before the 2,4GHz days, the 40 MHz FM and 27 Mhz AM transmitters had no issues penetrating the water.

If this were to work in a boat with a 2,4GHz radio, the antenna must be above water when the boat is floating half submerged sideways.

I can't say I've seen a working floodchamber in a cat.

My guess is the position of the floodchamber will counteract a workable CoG, as the battery in the sponson (I'm assuming the battery is a series connected set to keep the CoG as low as possible), acting as a floodchamber, would have to be in it's own watertight case.

With the battery on the tunnel, the boat would never want to flip up again, as the GoC would be too low (floating upside down and sideways).

The boats ran on the much heavier NiMH cells (which were ran submerged in the floodchamber to get the CoG right), maybe the lighter Lipo's will allow such a trial to be successful.

Give it a go!

Regards, Jan.
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Last edited by pompebled; Sep 05, 2014 at 03:38 AM. Reason: typo.
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Old Sep 21, 2014, 10:02 AM
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Anybody think this could be made with a flood chamber..or is it too small.

Small Bolt http://www.rcmodel.com.au/rtr-rc-boa...-boat-red.html

I'm thinking if the hatch was re designed with more of an oval at the top and weight to one

side similar to the atomik barbwire..might work in a similar fashion for self righting without a flood.

Unlikely but just thinking here...
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