[justcrusin]

Thats what they will be calling it in 30 years from now :shock:

Anyway after last weekends hatch installation stuff up and me getting that sinking feeling. I not being one to go to extremes :shock: went overboard as per usual and proceeded to fill sections of the yak with gp2 foam floatation.
A WARNING TO YOUNG PLAYERS!
Foam expands faster when chemical is lumped together.
eg:
If foam is poured in spread out it expands about 1 to 4 or 5
If the foam is poured into a bulk blob it expands at around 1 to 10, i believe because of the extra heat making the chemical reaction greater.

But after a couple of near disasters (luckly i was mixing and pouring the foam in 500ml lots) the foam was complete.

I filled the yak in three main areas from the rear to half way through the rear well.
From around 100mm rearward of the front hatch back to around the rear end of the footwell.

The results were very encouraging. A pool launch and i filled the front hatch completely with water. The results:

POSITIVES
Could not get the yak to sink.
Still very much normal stabilty.
Even sitting at the bow stabilty was good and wouldn't sink (see pics)
Heavy but very paddledable (i think i just made that word up :? )
Rollover from capsize the same as normal.
Reentry from water same as normal.

NEGATIVES
Weight gain of estimated 5kg
Foam is very messy and dangerous wear PPE
loss of front hatch storage space under footwell

All in all i am very happy with the results. The rear well one way bung were however a waste of time. yes they let the water out but let in back in to :?

Cheers Dave

 

[Peril]

Dave, how much weight have you added to the yak?

 

[JB]

Someone a call greenpeace there is a white minked whale on a kayak in some fulla's pool.

But seriously - 5kgs is not a heap of extra weight and when distrubted over the lenght of the yak not much at all.Does the foam hold much water as this could be an issue and add to the weight of the yak?

Could the manufacturers make a yak with internal bulk heads in. You know like pontoon ali boats (stabi craft for one). Might be a serious option in the future for a serious designed fishing yak. maybe

 

[Dodge]

After your dedication to the project pleased to see it went well Dave; certainly a good test you gave the yak and well done

 

[justcrusin]

Peril, haven't weight her in yet but I can still carry it by myself quite easily.

JB you gotta be a kiwi what the hell is a fulla :lol: but internal bulk heads would be a excellent idea (O.K. you listening).PS it's not fat i just the camera just didn't get my good side. :lol:
The foam is design for floatation and i have been told that it shouldn't hold water. When compared to say fullafoam the cell's are a lot smaller on the gp2.

Cheers Dave

 

[Peril]

JB you gotta be a kiwi what the hell is a fulla :lol: but internal bulk heads would be a excellent idea (O.K. you listening).PS it's not fat i just the camera just didn't get my good side. :lol:

Cheers Dave

I think he means fella, although to Aussie ears, the Kiwis say filla, not fulla. Fulla would be what we hear when they say filla!

On one of my early trips to NZ some years ago, one of the locals kept pestering me to say six, because it sounded like sex to him. Happy to oblige and keep him amused for an indecently long time

 

[DGax65]

POSITIVES
Could not get the yak to sink

Dave, that is a big positive.
Will that GP2 foam always resist absorption, or does the outer cured layer need to be intact? The foam that I used around my battery box definitely absorbed water. It was alright at first, but after the top layer got dented and crushed a little, it soaked up water like a sponge. The U.S Coast Guard had that problem on their Boston Whalers. They got cracks and delaminations in the gelcoat/fiberglass that allowed water to slowly wick through and get absorbed in the foam. After a while, some of the boats were too heavy for their trailers. Depending on how fast the foam absorbs, that could be a serious problem on a kayak. You could wind up with a flooded yak and no way to pump out. You might want to weigh the yak on occasion to see if it is absorbing water. I'd like to try the foam in the bow and stern of my yak. Not too much; just enough to provide some additional buoyancy, while not losing much internal storage. I think that I'd try filling thick poly bags with it and then molding the bags to the contours of the hull while still pliable.
Those pictures remind me that I still need to sink test my X-Factor with the inflatable fenders in the hull. My previous test didn't look as effective as your foam fill. What percentage of the internal volume do you estimate was filled with foam?

 

[justcrusin]

Gday doug,
Hopefully i won't get enough water in now i have put a new screw hatch in the rear. (still wish i'd never touched it now) to have the foam absorb that much.
If the whalers had that problem it very well could be the same type of foam, I'll keep an eye on it. However there's would be presure injected were mine was a hand mix so it may be different, would be worth me looking into.

I used 8 litres of foam unmixed so with a rough estimate of a 5 to 1 expansion thats 40 lts of foam the spread was even so it should be 20litres front and 20 back.

One the poly bags, probably no need the foam won't stick to the yak hull.

Working on the percentages the us coast guard boats would be in the water in rougher conditions than my yak and for a lot longer time so hopefully things will be alright .
At a pinch i could cut the foam out with a fishing knife the fact it won't stick too the hull should make it easy to get out if things go wrong. I filled both ends so its reach able

Cheers Dave

 

[DGax65]

Dave
I considered the problem of poly bags not sticking to the hull. I thought that once the bag was in place I could put a small amount of foam on the hull and edge of the bag. I've done this before in preparing equipment for shipping. We used the poly bags to keep the foam off the equipment rather than keeping water out of the foam. Either way it is the same basic idea. As long as you're only worried about keeping a foam bag in place, a small bead of foam around the edge will keep it in place. I think the bow will be easy, but the stern might be a little more difficult. Thanks. You've got me excited about trying this.

 

[justcrusin]

Gday Doug,
You got me round the wrong way. It's the foam that won't stick to the hull. It sort of sticks but pull away very easily.
It does stick to everything else like Sh*^% to a blanket.

Cheers Dave.

PS If you haven't already cut a hatch in the back i would reccomend not doing it. This was the cause of my problems in the first place up untill then i didn't get more than a thimble full in.

 

[Davey G]

interesting jc32. i was gpoing to put the extra hatch in the rear of my new prowler elite, but now..... :?: :roll:

was the leak just due to a bodgy effort on your part, or does this area of your yak sit under the waterline? Mine sits high above the water level so i can't see how it should be such an issue?

 

[justcrusin]

Gday Dave,
The area is normally dry but the reason i cut the hatch in was to mount the transducer and the battery back there out of the way. That and the new anchor in the back well and my fat arse there was one or two centimeters of water in there.
At first i thought i had done a dodgy silcone job but on closer inspection the screw hatchs just arn't up to the job.

If you look at the hatch in your seat theres a lip at the top and another on the bottom making a double seal. The ones available over the counter a cheapo's and only have one rubber seal and basically the seal leaked. It did take an hour and half to get there as more water got in the back got lower letting more water in and so on.

Really have a good think if you need the hatch. I reality i didn't just thought it would be nice.

My advice would be don't do it.

Cheers Dave

PS after draining the water on the beach i moved the anchor and the battery to the front compartment and paddled around 1.5 k back to the launch site and no water got in. However the extra weight in the front made for some very tough paddling. So i believe the prowlers may be a bit trim sensitive.

 

[Dodge]

.

Really have a good think if you need the hatch. I reality i didn't just thought it would be nice.

My advice would be don't do it.

Dave if you still have reservations for peace of mind why not restore the status quo, silicone the lid into place permanently into the holding outer ring, or remove everything and weld the cutout hull plastic back in place which is pretty straight forward for a pro plastic welder

 

[DGax65]

Dave
A couple of observations:
I thought about mounting a small hatch in the same spot on my first Prowler 15. The P15's lack of access to the after half of the hull is a problem. That angled section at the rear of the tankwell is just begging for a hatch. Unfortunately, it is just a little too curved to get a good seal on the hatch flange. A small (4inch) hatch will be almost flush with the hull, but a larger hatch will have a gap. You can get around this by using a heavy bead of Sikaflex or a gasket and tourquing down the bolts nice and tight. This should provide a good seal for splashes, but it may leak if constantly submerged.

A little silicone grease on the O-ring and threads really helps maintain a good seal. I had an 8 inch hatch just forward of the seat on my P15. It leaked a little until I started using the silicone grease. The only problem with using silicone grease is that if sand gets on the O-ring or threads it will be nearly impossible to get rid of without removing all the grease. This didn't bother me much, as I only used the hatch for mounting the transducer and routing cables during the initial install. I just put some silicone on it, snugged it down with a spanner wrench and never worried about it again.

I've had good luck getting foam to stick to the polyethelene hull. I just rough up the surface with some coarse grit sandpaper and I get pretty good adhesion. This also helps with silicone adhesive and Sikaflex.

 

[justcrusin]

Dave if you still have reservations for peace of mind why not restore the status quo, silicone the lid into place permanently into the holding outer ring, or remove everything and weld the cutout hull plastic back in place which is pretty straight forward for a pro plastic welder

Gday Richo, already done mate siliconed the lid on yesterday went out today and not a drop of water in the hull.