What's Inside a Float Tank?

[Black_Fly]

I'm getting prepared to install lining holes on 2 canoes, a Wenonah Prism, and my latest acquisition, a NS Magic. A reputable small boat repair shop owner said he wouldn't take money to drill through a float tank. I'm wondering now why he was hinkey about the process. What's inside there? Styrofoam? Hydrogen gas? Nitroglycerin?

 

[yellowcanoe]

Air.. Probably he does not want to have someone come back at him if the hole enlarges around the PVC tube and floods the tank. Lining holes are usually done in boats without float tanks. There usually is a little one way valve in the tank of composite canoes but that is carefully engineered and out of the water. The valve is a safety expansion valve.

Some others like Grumman had styrofoam.

You can make a lining bridle for a composite boat.

 

[Dagger]

Nitroglycerin is right

 

[Jim Dodd]

I could go for pumping Helium in mine !

Until I can find some. I'll stick with air.

Maybe RAKA has it ???

 

[Midwest Firecraft]

You can always e-mail Northstar, but they have closed cell foam, so there is no worries with drilling into it.

 

[Odyssey]

"You can make a lining bridle for a composite boat."

Yes, precisely. If you're squeamish about perforating your boats, and I wouldn't blame you, then learning the ropes might be the way to go.
You could try and practise the rope method and see how it goes. If you really don't like it then drill away. Just a thought.

 

[Black_Fly]

Yeah, I'm pretty good with ropes, just seems like a lot of trouble.

Right now I'm considering the hard pvc approach I used on my Royalex boats, with the addition of some conduit flanges for durability.

 

[Guest]

Yeah, I'm pretty good with ropes, just seems like a lot of trouble.

Right now I'm considering the hard pvc approach I used on my Royalex boats, with the addition of some conduit flanges for durability.

Maybe less trouble than a leaky floatation chamber. You seem determined to try installing low lining holes, so let us know how it goes if you do drill holes in your float tanks.

Be aware going in that using some kind of PVC pipe passing through a flange will require a much wider flange than the one shown in the photo on the other thread. In that stem accessible DIY lining hole the tubing was installed on the outside of the protruding flange sidewall.

With a sealed float tank you would need a flange with an interior diameter the size of the OD of the PVC pipe. That could be an intimidatingly large hole to drill, and the PVC pipe or whatever better fit inside the flange near perfect tight.

I have drilled a lot of holes through canoes, RX lining holes, spray skirt rivet stud holes, even some holes for DIY rudder controls, but a large hole through a float tank, near the waterline, in a composite hull would give me pause.

As suggested multiple times using a bridle may be a better solution and I would at least experiment with a bridle before drilling a large hole through a float tank.

One alternative to lower lining holes is to use a lining bridle. This thread, or lots of how-to videos.

http://www.canoetripping.net/forums.../general-discussion/31556-canoe-lining-bridle

You can make a lining bridle for a composite boat.

If you are inexperienced lining a canoe some low-hazard lining practice would be a good idea in any case.

 

[Odyssey]

I actually don't mind the looks of the tug eye solution, just seems like a lot of trouble. I am by no means an experienced river tripper but even I can throw a loop around a loaded canoe to line it in less than 3 minutes. I prefer the control between the water line and the gunnel, not underneath. I'm not towing it, I'm working with the current. The tug eye would be at this same level albeit further forward. I consider the trip being about the journey, not merely the daily destination, so it's about as much trouble as dealing with beaver dams, rocky put-ins, muddy take-outs, rooty portages, bouldery wades...
But sincerely best wishes and good luck to the float tank exploration, I'm sure it will turn out great.
FWIW I'd guess plain boring old air is inside floatation chambers. But if you find nitro please get it on video!!

 

[Guest]

I consider the trip being about the journey, not merely the daily destination, so it's about as much trouble as dealing with beaver dams, rocky put-ins, muddy take-outs, rooty portages, bouldery wades...

As before, I have snagged lining hole painters and loops in sticky areas

Having a painter line attached further up the stems is less likely to get tangled on sticks or branches on small streams or dragging over beaver dam

Frustrating when the canoe suddenly fights back when sliding it across while balancing atop a mound of sticks, but at least I’m standing there alongside the canoe to free things up. I caught a floating limb through a low hung painter line and no amount of backing up, whacking it with a paddle or bouncing around would dislodge it. I had to find a place to put ashore and disentangle it.

FWIW I'd guess plain boring old air is inside floatation chambers.

It is a good question. I know from repairing float tanks that some (most?) seem to be just air, but it would be worth asking Wenonah and Northstar directly. Let us know the manufacturer’s answers.

If the chamber is filled with closed cell foam or etc forcing a piece of PVC pipe through would be impossible. Probably need to run a spade bit through it from either side. Or cut some hole saw type “teeth” on the end of the pipe and twist grind that around to work the pipe through the foam.

The hardest part with a foam filled chamber could be getting the alignment just right, so when the PVC pipe got to the far side it married up with the other flange hole sight unseen but precisely. Get the pipe close and stick something in from the other side as a guide through the hole or flange?

Don’t know, never done it. Not trying to dissuade you from the attempt, I’d just want to know more as I considered it, and have a look at what size flange I’d need to drill a hole for in order to pass a piece of PVC pipe through. Big flange unless you use skinny lining ropes.

BTW, on the DIY tug-eyes built from conduit flanges and hose it took some searching to find the almost perfect diameter hose. “Almost” perfect, I needed to sand down the protruding sidewalls of the flange before installation to have any hope of forcing the hose in place, even with some G/flex as lube.

Any tips or tricks from folks who have installed lining holes through float chambers? Maybe it is easier than I think.

 

[Mason]

It is easier than you think. See my earlier post. I've done two or four Wenonahs and a Clipper. All with spade bits and epoxy. All fiberglass or Kevlar. At least one of the boats has been in the drink multiple times, flatwater and rivers.

​​​​​​Also, your boat won't sink if you have waterproof bags tied in, unless you're packing water or something denser. Even with a leak in the float tank, and an empty boat, it will sink only very slowly (of course depending on how bad you butchered the job). Race boats don't even have floatation, though some add some foam under the gunnels. The tiny float tanks on most tripping boats aren't going to save the boat in whitewater, where you need extensive floatation.

 

[Mason]

Here are two pics of glass boats with my hack job. Both were done over 25 years ago, with no touchup.

 

[Black_Fly]

Hmmm, throwing a hitch is sounding better and better. I've been lining my Kevlar boats tying off to the handles. Works, but not ideal.

Update: decided the angle of the hull is prohibitive with a solid flange, hard pvc. I'm done. A hitch it is

 

[Black_Fly]

Here are two pics of glass boats with my hack job. Both were done over 25 years ago, with no touchup.

Hey Mason,
How did you keep that small seam from leaking?

 

[Mason]

Epoxy. Just smeared it on the PVC and the holes when I installed it. Then wiped up the waste. That seam is just clear epoxy. The piece of PVC is longer than what you need. After it cures, cut it off flush with a saw (e.g. hack saw blade) trim, and bevel. You can protect the boat from saw scratches with painter's tape. Fine trimming with a sharp knife or chisel.

 

[Alan Gage]

It is easier than you think. See my earlier post. I've done two or four Wenonahs and a Clipper. All with spade bits and epoxy. All fiberglass or Kevlar.

Epoxy. Just smeared it on the PVC and the holes when I installed it. Then wiped up the waste. That seam is just clear epoxy. The piece of PVC is longer than what you need. After it cures, cut it off flush with a saw (e.g. hack saw blade) trim, and bevel. You can protect the boat from saw scratches with painter's tape. Fine trimming with a sharp knife or chisel.

I use the same method with no problems. I did buy a regular drill bit sized to the PVC I use for a little cleaner holes. The spade bit in particular tends to blow out on the exit side so once the extended tip of the bit just starts to show through on the outside of the hull I use that as a pilot hole and finish off by drilling from the outside on the opposite side of the hull. Just keeps it a little cleaner.

Alan

 

[Odyssey]

Would a hole saw cut cleaner than a spade bit?

 

[Alan Gage]

Would a hole saw cut cleaner than a spade bit?

Probably. I wonder why I didn't use one? Maybe I was worried about it it catching, like hole saws sometimes do, and ripping out a chunk of hull? Sometimes there's a reason I can't remember and sometimes it's just because I didn't think of it.

Alan

 

[Guest]

It is easier than you think. See my earlier post. I've done two or four Wenonahs and a Clipper. All with spade bits and epoxy. All fiberglass or Kevlar. At least one of the boats has been in the drink multiple times, flatwater and rivers.

Well, the pipe-through-hull does seem easy enough. If I ever have a composite WW tripper I will perhaps consider it.

​​​​​​

Also, your boat won't sink if you have waterproof bags tied in, unless you're packing water or something denser. Even with a leak in the float tank, and an empty boat, it will sink only very slowly (of course depending on how bad you butchered the job).
The tiny float tanks on most tripping boats aren't going to save the boat in whitewater, where you need extensive floatation.

One composite canoe with really teeny float tanks sank very quickly, and for a worrying long time.

Friends Chip and C2G were helping with a canoe review, paddling a brand new carbon Bell Prospector. A loaner Bell Prospector minimal gear and no outfitting, nothing tied in. Someone had earlier remarked that the Bell Prospector had the smallest floatation chambers they had ever seen.

Putting the canoe through its paces Chip and C2G attempted an attainment, up a fast, deepwater section of the Susquehanna, at the head of a calm pool between two tall cliffs. The attainment was decidedly unsuccessful.

We got the swimmers to safety, which took some time. The canoe was still nowhere to be seen. My first thought was that it was trapped under a cliff in some undercut. My second through was “How am I going to explain this to Bell?”

An interminable amount of time later the Prospector finally – barely - broke the surface a good hundred yards downstream in the calm pool.

That was the second time C2G, who is a skilled paddler, had dumped a canoe during an attempted attainment, so there was that lesson.

Other lessons were learned; I have D-rings and other tie down points to secure gear or floatation in every canoe we own. And the buoyancy equivalent of a float tank or two in the form of permanently installed knee bumpers and other minicel pads, so even on empty boat day paddles the canoes have some added floatation.

 

[Black_Fly]

Mason, do you drill at the angle of the pipe or perpendicular to the hull? Pilot bit size?