Math question

What is the bouncy displacement of a noodle?

3.5" dia. With a 1" hole. 30 ft long ( down both gunnels )

Something like 3.14 x 1.75" squared x 360" - 3.14 x .5 x 360"

= volume in cubic inches? X .0043290 = gal. X 8 lbs = displacement in lbs.?

First answer gets a cookie!

Maybe I should just put a six " in chunk in a ice cream pail and check it?

And that is today’s puzzle. It is actually a safety question.

I put orange noodles down both sides for:

Comfort, leaning a knee on angle alum. Hurts



Boat protection


Safety , reduces bumps and bruises.

Hauling on car it doubles as hauling pads.

Loading slide it on the car.

Stability it has to help stop tipping some. (We are planing to test it)

Just wondering how much floatation if we got swamped would it still keep us up to get to shore? Or maybe bale back out?

How many pounds of gear tied to canoe would it float if it all goes to the bottom that would be bad.

My math shows 52.098 litres volume of foam noodle (before coffee). Finding a buoyancy number for polyethylene foam though?

I had pho noodles for lunch
but not that much. That’s insane.

Without gear
I have seen canoes with splash guards( thats what you are describin) at the bottom of the Kenduskeag pinned to a rock

Come to the race Sat and you will find hundreds of canoes so outfitted… The purpose is to help keep Six Mile Falls out of the canoe. Just below Six Mile is a rock garden… Several again will be pinned there underwater with splash guards on…

Splash guards are not dump guards.

That would be
52.098 x .264 = 13.75 gal. At 8.3454 per gallon = 114.7 lbs of displacement. At 100 % displacement

The noodles may go .7 lbs so 114?

I got a different #

Splash guards
I forgot about that one we got hit by a huge wake last year and did not get wet.

We are flat water paddlers but you just never know.

Yep, that’s it
Buoyant force 115 pounds. Net buoyant force will be that minus the weight of the foam. If the foam has a specific gravity of, say, 0.2, then the net buoyant force would be 0.8 times the 115 pounds = 92 pounds.

Physics problem

– Last Updated: Apr-23-15 7:31 PM EST –

Something must be submerged in order to displace water. In order to provide buoyancy the foam on your gunwhales would need to be underwater. By definition, when your gunwhales are underwater you are no longer floating.
Therefore, buoyancy added by foam on gunwhales=0

Edit to add

I suppose it would cause your boat to sink to the bottom at a slower rate than if you did not have it but with 30 years of shipbuilding experience I would not put that in the win column.

Except when

– Last Updated: Apr-23-15 9:10 PM EST –

If the canoe is right-side up but full of holes and the weight of the boat is less than the foam buoyancy, the foam on the gunwales would (marginally) support the canoe.

If the canoe is capsized, then the gunwales would be submerged and the foam would be providing buoyancy.

And not physics, say hydrostatics, it makes me happy....

15 ft of noodle
Will not sink with 100 lbs of weight.

So if they are both attached to the canoe. It will not sink!

The floatation built in to the canoe should float it and the noodles will float 100 lbs of gear.

I understand the hydraulic force of water. And that a strong current can easily over come this much flotation.

But on on flat water it should keep the added battery and trolling motor from sinking.

I have been thinking about adding an inner tube (want to calculate that one? LOL) around the battery box. And some air bags.

I can’t think of any con’s to air bags except space for gear.

Due to my physical condition I’m not walking out or swimming very far. So I’m thinking lots and lots of floatation.

The noodles will help but. At this point flotation is my friend.

Lots and lots of flotation. :slight_smile:

salt water, freshwater or heavy water?NM

Dear Board,

Adding floatation above the water line just adds weight and reduces a boats carrying capacity by the weight of the added floatation.

Real boats, ie powered boats have the floatation added under the deck not above it.

A better solution would be to add the foam noodles as sponsons along or just slightly above the weighted water line.

SportsPal has been doing that 50 years on their canoes. You could probably buy replacement sponsons from Meyers or Raddison and figure out a way to attach them.


Tim Murphy AKA Goobs

Not just sink at a slower rate though

– Last Updated: Apr-25-15 2:15 PM EST –

With enough flotation on the gunwales, the canoe can get swamped but not sink, so at least you won't lose your boat and all the stuff that's in it. Also, it would be the best way to ensure the boat stays upright when swamped, because the weight would be between and lower than the points of support. I'm not saying this is the best method of installing flotation, but it has some merit.

One other thing
Dear Aquanaut,

If comfort is main goal, as in you don’t like to lean or kneel against an angled aluminum gunnel then why not just get a piece of foam pipe insulation and some double sided Velcro tape and add padding where it is required?

It probably wouldn’t cost you more than $ 10.00 for an 8 foot piece of pipe insulation and some Velcro tape. If it wears out toss it and buy some more.


Tim Murphy AKA Goobs