[justcrusin]

Gday all
Been thinking to much and have come up and been toying with the idea of filling the yak with full o foam for positive floatation.

Reasons
1. saftey factor of positive bouyance even if you get holed.
2. the stuff in the front hatch keeps sliding to the back of the yak. The one that is really annoying is the wallet and keys in a dry bag and the first aid kit.

Negatives
1. might create to much bouyancy and the yak could ride to high becoming unstable
2. full o foam expands and gets hot during the chemical reaction, either melting the hull or deforming it from the expansion
3. cutting holes in the yak to reach all the mid section

The plan
1. Fill in small sections starting in the middle and working back both ways
2. forward area access through front hatch
3. Rear access cut 100mm holes in rear and fit screw hatches. The rear well has a space for this
4. fill from center of yak out in 100mm lots to help heat and expansion
5. be carefull of the rudder wires cause full of foam sticks like s*$t to a blanket and will jam the cables
6. trim foam to neat finish and sqaure sections around new hatches for more storage

Thats the plan has anyone tryed this or can see any problems i may have not anticipated before i destroy my new yak.
The other option was to buy some foam floatation blocks cut them to size and fit them in. Maybe just a 200mm strip in either end then sealed with silicone to create three water tight areas

Or have i just gone nuts :?:

Cheers Dave

 

[Dodge]

2. the stuff in the front hatch keeps sliding to the back of the yak. The one that is really annoying is the wallet and keys in a dry bag and the first aid kit.

Dave possibly simpler to just put half a dozen pool noodles in the yak for flotation.

To locate the drybag, just put a saddle inside under the deck [you only have bolt heads outside so looks neat] and have a cord from bag to saddle, and big gear in a landing net refill also tied off to saddle

 

[Peril]

Negatives
1. might create to much bouyancy and the yak could ride to high becoming unstable

Impossible. You will be adding a small amount weight to the yak, not removing it, so it will not sit higher

 

[Polar]

JC32 - mate , you are a thinker- love to hear how it turns out. Be great if you could pick up a cheap 2nd hand or slightly damaged yak to trial this process on. best of luck

 

[DGax65]

I've tried foam on two of my yaks and I doubt I'll ever do it again. I used an expanding foam that comes in an aerosol can. When I did the stern on my Prowler I shot it into a blind space with poor results. I didn't get anywhere near the expansion that I was expecting. I filled through a single hole and the result was a ralatively small, very dense plug of foam. I know that there are other types of foam that expand more, but I was worried about deforming the hull if the foam got too hot. The canned stuff doesn't seem to create much heat as it expands. I also used this foam to create a conformal bedding for my battery box to rest on. The large rear hatch on my Malibu X-Factor allowed me to carefully control the application of the foam. I got much better expansion, but I still wasn't satisfied with the results. The foam held my battery box firmly in place and adhered well to the hull (surface was sanded). The big problem that I had with the foam was that, after the hard-cured surface got crushed or scratched, it started to absorb a lot of water. I couldn't get the water out and it started to smell pretty bad. I eventually ripped all of the foam out. I might try the foam again, if I could find some that sets up hard and wouldn't absorb water. I have gone back to using inflatable fenders stuffed inside the hull. Even if the entire hull is full of water, there is enough bouyancy provided by the fenders to keep the yak at the surface. They won't keep you out of the water, but they will definitely keep the yak from sinking completely. I'm toying with the idea of installing a bilge pump in my X-Factor. I'm not sure it would be worth the trouble, but it would be a fun project to try.

 

[justcrusin]

Thanks Doug,
On that I think i will can that idea for the moment.
I know you can buy blocks of pre made foam floatation like those used under thwarts in tinnies. Given where there used they shouldn't hold water. I might get a couple and start shaping them to fit in the hull.
Will let you know how it goes

I smell bad enough imagine what the GF would say if they yak smelt too :shock: :lol:

Cheers Dave

 

[troppo]

One place where I worked they wanted a series of 44 gallon drums filled with foam to use as floats for a water-pump intake pipe line. Someone (not me!) read the instructions on the foam mix, calculated amounts, mixed the chemicals together, quickly poured the 'right' amount into the 44s then sat back. When the foam started to creep out of the tops of the 44s and keep on coming . . . and coming . . . and coming, the numbers were crunched again to find that they were out by a factor of 10 or something. The rest of the day was taken up with cutting up the massive amount of excess foam and trying to hide it somewhere.

 

[PeterJ]

Below the floor on my stinky i have about 80 3 litre plastic coke bottles in there ,sealed.

 

[Daveyak]

Before you consider using expanding foam to fill a kayak, have a read of the following story. I found it on the 'net and posted it quite some time ago but worth submitting again for newer forum members to enjoy.

A friend of mine once built a canoe. He spent a long time on it and it was a work of art. Almost the final phase was to fill both ends with polyurethane expanding foam.

He duly ordered the bits from a fibreglass supplies shop and it arrived in two packs covered with appropriately dire warnings about expansion ratios and some very good notes on how to use it. Unfortunately he had a degree, worse still two of them. One was in Chemistry, so the instructions got thrown away and the other in something mathematical because in a few minutes he was merrily calculating the volume of his craft to many decimal places and the guidelines got binned as well.

He propped the canoe up on one end, got a huge tin, carefully measured the calculated amounts of glop, mixed them and quickly poured the mixture in the end of the canoe (the two pack expands very rapidly).

I arrived as he was completing this and I looked in to see the end chamber over half full of something Cawdor's Witches would have been proud of. Two thing occurred to me, one was the label which said in big letters: "Caution - expansion ratio 50:1" (or something similar) and the other that the now empty tins said "approximately enough for 20 small craft"

Any comment was drowned out by a sea of yellow brown foam suddenly pouring out of the middle of the canoe and the end of the canoe bursting open. My friend screamed and leapt at his pride and joy which was knocked to the ground as he started trying to bail handfuls of this stuff out with his hands. Knocking the craft over allowed the still liquid and not yet fully expanded foam to flow to the other end of the canoe where it expanded and shattered that end as well. A few seconds later and we had a canoe with two exploded ends, a mountain of solid foam about 4ft high growing out of the middle, and a chemist firmly embedded up to his armpits in it.

At this stage he discovered the reaction was exothermic and his hands and arms were getting very hot indeed. Running about in small circles in a confined space while glued to the remains of a fairly large canoe proved ineffective so he resorted to screaming a bit instead. Fortunately a large knife was to hand so I attacked the foam around his hands with some enthusiasm. The process was hindered by the noise he was making and the fact he was trying to escape while still attached to the canoe.

Eventually I managed to hack out a lump of foam still including most of his arms and hands. Unfortunately my tears of laughter were not helping as they accelerated the foam setting. Seeking medical help was obviously out of the question, the embarrassment of having to explain
his occupation (Chief Research Chemist at a major petrochemical organisation) would simply never have been lived down.

Several hours and much acrimony later we had removed sufficient
foam (and much hair) to allow him to move again. However he still looked something like a failed audition for Quasimodo with red burns on his arms and expanded blobs of foam sticking everywhere. My comment that the scalding simply made the hairs that the foam was sticking to
come out more easily was not met with the enthusiasm I felt it deserved.

I forgot to add that in retrospect rather unwisely he had set out to do this deed in the hallway of his house(the only place he later explained with sufficient headroom for the canoe - achieved by poking it up the stairwell. Having extricated him we now were faced with the problem of a canoe construction kit embedded in a still gurgling block of foam which was now irrevocably bonded to the hall and stairs carpet as well as several banister rails and quite a lot of wallpaper.

At this point his wife and her mother came back from shopping......

Oh yes - and he had been wearing the pullover Mum in law had knitted him for his birthday the week before.

 

[justcrusin]

Ouch don't know what would have hurt more getting the foam off your hands or the missus while she was killing him :lol:

Had a work mate did something similar, but he had a can o foam in his tool box that fell over and the nozzle got pushed on filled his tool box up with foam. He spent the entire day cutting and scraping his tools free.

Cheers Dave

 

[JD]

I bought a second hand white water kayak a few years ago, it was filled with the old bladders from wine casks. The bloke had just blown them up and pushed them in. Cheap and easy except for the headaches.

 

[Scott]

JD, all you need is someone with a taste for cheap wine to empty the wine casks for you. The best thing to use, however it wouldn't be as cheap as your excellent wine cask idea is to use crosslinked closed cell foam. (this is what is inside a PFD to make it float.)

It is available in sheet form from Clark rubber ect up to 50mm thick. It can be easily laminated together using standard contact adhesive however the cheapest and easiest way to do it is to use pool noodles as previously mentioned which is also crosslinked close cell foam. For making bulkheds however the closed cell in sheet form is perfect.

Catch ya Scott

 

[YakAtak]

Daveyak, thanks for the mid afternoon entertainment, really made me feel a lot better about that degree I don't have. Classic. :lol:

 

[troppo]

There are some great stories about foam. Just love that one of yours Daveyak.

 

[Phoenix]

Daveyak - that is one funny story

 

[Guest]

I cannot stop laughing Dave, anyone who is thinking of using expanding foam please invite me over just on the off chance something goes wrong I wouldnt want to miss it, I will bring a carton and some corn chips and safety googles (to stop my tears from laughing too much from wetting your floor).