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Positive buoyancy foy kayak

Posted: Sat Jan 09, 2016 10:46 am
by AshG
Anyone use pool noodles as an added safety feature for their kayak?
I know some are designed with it built in, but my kayak is only a little 2.8m creek basher the same as the dream kayak style that every man and his dog has copied and now sells, but I have about 20kg of fixed added weight in the way of a deep cycle battery and motor. If the inevitable happened and the hull spilt from whatever reasons, shark bite, rock strike, ninja attack whatever, my deck isn't watertight, never will be, and it would fill with water.
Was thinking if I just work out the weight of everything on board including the weight of the kayak, then using barbell weights I have at home to the same weight that I work out my kayak is plus what it carries, then in the pool, just keep adding noodles till it floats the weights....? Seen afew posts floating around the Internet with calculations etc but without real world testing, you really don't know the actual amount of buoyancy of one noodle to the next... I estimate 50kg max is what I need to keep afloat, kayak 25kg, motor 6kg, battery 13kg with afew extra kgs spare...
Anyone else done something like this? I can't see many noodles being required as I weigh 78kgs and one noodle easily floats me in the pool, without testing I reckon maybe 3 or 4 is all it will take, I'll have a play in the pool later on with the kids and see what happens, interested to see if anyone else has done something like this?

Re: Positive buoyancy foy kayak

Posted: Sat Jan 09, 2016 11:11 am
by simons rat
I had the same thought as you with one of my kayaks which I use in estuaries and stuffed 6 pool noodles into the hull. Never sunk it to find out if it works or not ... just gives me some mental insurance.

Be interesting to see if anyone has any practical experience with this.

Cheers,

S

Re: Positive buoyancy foy kayak

Posted: Sun Jan 10, 2016 7:32 am
by gbc
I had a few (6) in the old scupper pro I used to use in the ocean. Cheap insurance. As for actually calculating how many, are required, I can't help, just applauding your logic.

Re: Positive buoyancy foy kayak

Posted: Sun Jan 10, 2016 6:16 pm
by Smylea
Another option is to fill the hull with bean bag beads (will flow into all the nooks and crannies while providing positive flotation at minimal weight).

Ray

Re: Positive buoyancy foy kayak

Posted: Mon Jan 11, 2016 3:59 pm
by Plakkyboat
Buy a couple of rubber bungs to suit a 10mm hole. (Super Cheap)

Drill a couple of 10mm holes into your hull (above the water line) in normally inaccessible areas of your hull.

Buy a can of spray foam (Bunnings) with a filler tube connected to the the spray can.

Insert the tube through the 10mm holes and fill the space as much as you practically can.

Insert the rubber bungs into the holes.

VoilĂ 

Re: Positive buoyancy foy kayak

Posted: Mon Jan 11, 2016 4:50 pm
by AshG
Not gonna spray the hull with expanding foam or bean bag beans, pool noddles will do the trick I think. I've got steering cables, motor tilt cables, switch wiring and storage room in the hull.

Re: Positive buoyancy foy kayak

Posted: Mon Jan 11, 2016 9:05 pm
by nqkayaktours
Smylea wrote:Another option is to fill the hull with bean bag beads (will flow into all the nooks and crannies while providing positive flotation at minimal weight).
Not a very good idea at all. :roll: If the shit hits the fan then they beads are floating everywhere. Fish eat them beads but cant pass them. So they die. Not good.
But feasibly you are right. If you fill the hull displacement with pool noodles, or empty milk/coke bottles, will give you less water and more bouyancy. But probably wouldnt be real stable to paddle. But at least you can stay with your floating yak. :grin:

Cheers and tight lines,
Ian

Re: Positive buoyancy foy kayak

Posted: Mon Jan 11, 2016 9:52 pm
by tonystott
Hobie includes enough foam to keep my (empty) Tandem Island main hull afloat...I added 2 of the bigger noodles (the ones with a central hole in them) down each side (presumably they would float up into the gunwales if the hull was flooded) plus another one cut in half and tied together in the forward hatch area.

I didn't bother working out the precise flotation of each noodle, as (a) my own swimming pool experience showed that a single noodle will keep me floating, and (b) my Island has two amas which provide an additional 300kg total of flotation.

Re: Positive buoyancy foy kayak

Posted: Mon Jan 11, 2016 10:45 pm
by AshG
nqkayaktours wrote:
Smylea wrote:But probably wouldnt be real stable to paddle. But at least you can stay with your floating yak. :grin:

Cheers and tight lines,
Ian
Yeah, I'm not expecting it to be able to be paddled, just keep it at the water line so I can swim it to the bank and salvage it easily... if the occasion ever occurred, touchwood it doesn't...
Had the hull half full of water after an unexpected very strong wind (thanks willy weather) blew up whilst out on the dam and the water from the relentless chop got into the now covered and sealed but wasn't at the time access hatch (lesson learned there haha) stability went out the window and was very touch and go, only just made it back to the bank afloat :ops:

Re: Positive buoyancy foy kayak

Posted: Mon Jan 11, 2016 10:53 pm
by laneends
You may be able to keep it afloat, but it wouldn't be stable enough to sit on, so bouyancy is really only so it gives you something to hang on.
to, and salvage.

bouyancy, if foam needs to be closed cell. Expanding foam takes on water and can create pressure to deform or even split when filling. Hence pool noodles. just cram as many in as you can. i fill all non useable storage areas with them.

Using cheap inflatable items can be false economy as neglect will see them deflated when you need then.

empty sealed plastic soft drink bottles are an option also

Re: Positive buoyancy foy kayak

Posted: Mon Jan 11, 2016 10:57 pm
by laneends
AshG wrote:[
Had the hull half full of water after an unexpected very strong wind (thanks willy weather) blew up whilst out on the dam and the water from the relentless chop got into the now covered and sealed but wasn't at the time access hatch (lesson learned there haha) stability went out the window and was very touch and go, only just made it back to the bank afloat :ops:
How about a removeable bung, that you can poke a hand bilge pump with hose on end through (snug fit). That way you can bail it without opening any hatches.

Re: Positive buoyancy foy kayak

Posted: Mon Jan 11, 2016 11:37 pm
by AshG
laneends wrote:
How about a removeable bung, that you can poke a hand bilge pump with hose on end through (snug fit). That way you can bail it without opening any hatches.

I've usually got plenty of 12v power on board, smallest is the sounder battery which I have in the yak all the time so always have power on hand so thought about a small bilge pump with alligator clips, a small length of tube, be quick and easy to hook up and keep me hands free for the mad paddle (or motor) for the bank...

Re: Positive buoyancy foy kayak

Posted: Tue Jan 12, 2016 11:35 pm
by Plakkyboat
If you use pool noodles, be aware that they break down over time and become powdery and crumbly.
In fact, I just threw out 2 old ones today in that condition.
Maybe bottles would last longer and be cheap and easy to replace or remove.

Re: Positive buoyancy foy kayak

Posted: Wed Jan 13, 2016 8:39 am
by simons rat
Buy a can of spray foam (Bunnings) with a filler tube connected to the the spray can.
be careful of this ... some filler foam actual absorbs water.

Make sure you get foam that says it is designed for boat building.

Cheers,

S

Re: Positive buoyancy foy kayak

Posted: Wed Jan 13, 2016 8:53 am
by AshG
Plakkyboat wrote:If you use pool noodles, be aware that they break down over time and become powdery and crumbly.
In fact, I just threw out 2 old ones today in that condition.
Maybe bottles would last longer and be cheap and easy to replace or remove.
Yeah the kids pool noodles only lasted a year in the sun sitting around the pool, but I figure they should at least last that long inside the kayak out of the sun. $10 to replace them each year is cheap insurance in my eyes, and probably the cleanest easiest way to add flotation. Cheers for all the input people :)