Floatation that works please

[Froggy]

My boats are all 29 ins or less, there not allot that f room in my them for floatation however there?s as much as I can get in there.

I have a question for Panther6834 if you take a 5 gallon bucket of water or an 8oz bottle of water fill it to the very top with water and put a lid on it so there is no air in the bucket or bottle just water, will it float or be buoyant at all Or neutral
At tried it with a bottle of water in my lake, it sank like a rock I think the 5 gallon bucket would do the same thing, hence our boats filled with water.
Found on the internet.
The buoyant force on an object equals the weight of the fluid it displaces. In equation form, Archimedes? principle is
An object submerged in a fluid experiences a buoyant force
is greater than the weight of the object, the object rises. If It is less than the weight of the object, the object sinks. (b) If the object is removed, it is replaced by fluid having weight
.Since this weight is supported by surrounding fluid, the buoyant force must equal the weight of the fluid displaced.

I?m suggesting that we cannot rely on what we think is enough flotation material in our boats, I?m suggesting that we know the exact weight of our boats filled with water and that the flotation material in our hulls can create enough buoyancy to get the boat back to the surface.

After losing three in 6 months I?m not taking anymore chances.

[T.S.Davis]

Fun with google. Like we trust google. haha Found this with a simple search:

What is the difference between principle of flotation and buoyancy?

In summary, buoyancy is the upward force exerted by a fluid on an object, while flotation refers to the act or condition of floating on the surface of a fluid. Buoyancy is the resultant between the net force exerted by the fluid on the object (the buoyant force) and the weight of the object

The way "google" makes it sound......floating is on top of the water and buoyant means not sinking. Kinda. This is why the water inside the boat is irrelevant. It (the water) is less buoyant than the sum of the parts. We're confusing "floating" with not sinking.

A silly in my head and example...............
Tub full of water with a boat floating in it. Think tupper ware bowl. Now pour more water into the tub. That water just becomes part of the water. It doesn't sink to the bottom because water we poured has the same density as water in the tub. That is assuming they are the same temperature. Now pour water water into the bowl. Eventually it stops "floating" on top of the water. "Floating" stops when the water inside the boat joins the water outside the boat. The water in the bowl (after floating stops) becomes just another part of the water. If the bowl has no buoyancy it sinks to the bottom. If the bowl has buoyancy, it moves the bowel to the surface but it doesn't actually float. "Float" happens on top of the water.

Basically, the sum of our parts (the boat) has to be less dense than the water. The water IN the boat is only a factor while the boat is still "floating" on the surface. Once we've lost that battle we switch to hoping for enough buoyancy to recover it. How to get that just right is the mystery.

[Froggy]

Great analogy T.
The mystery has to be solved before my boats go back in the water

[Panther6834]

To answer that question, it depends on the weight of the container the water is put in. Again, if the total combined weight weighs less than the weight of the water displaced, the object will float. Take a small Styrofoam cooler, completely fill it with water, seal it, and place it in the lake...and, I guarantee, it will float. Do the same with a glass bottle (as you appear to have already done), and it will sink (as you discovered). Do the same using a container weighing the same as the water the container (not including the water) displaces, and you will have "neutral buoyancy". This is why some pallets can float, and others will sink...it depends on the type of wood they are made from, as different types of wood have different densities.

In all three cases, the 'difference' is the weight of the container vs the weight of the water that the container (again, not counting any water within the container) displaces. If you take any of your boats w/o battery, and place it on water, a certain amount of the hull will be below the surface. As a heavy object (such as a battery), and the waterline changes (ie. more of the hull is below the surface). Add more weight, and more of the hull goes below the surface.

As long as the weight of the boat & everything inside it weighs less than the displaced water weights, the boat will continue to float...tho, at the same time, the greater the amount of the hull will go below the waterline, and the closer the deck will get to the surface. Once the boat & everything in it weighs the same as the weight of of the displaced water, the top of the deck should be sitting right at the waterline. Now, if you add any more weight inside the hull, causing the boat to weigh more than the weight of the displaced water, that's when the boat WILL sink.

As you, and a certain naysayer, should easily be able to see, the "weight of the water" IS a factor in whether, or not, a boat maintains its ability to float. Truth is, this is all high school science...heck, for all I remember, this might have been covered in junior high science class. Using another age-old example, a pound of lead, and a pound of feathers, both weigh 1lb...but, a pound of feathers will float, whereas a pound of lead won't. Why? Because the lead weighs more than the weight of the water it displaces, whereas the feathers weigh less than the water displaced. Btw, I'm not advocating building a boat out of feathers.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

[T.S.Davis]

My boats are all 29 ins or less, there not allot that f room in my them for floatation however there?s as much as I can get in there.

About 20 years ago I bought a boat and bunch of gear from Fine Design. He asked cuz he always did.....what are you putting in this? I told him. Bandit El Lobo. Great big brushed motor. A pile of sub C Nimh cells. It was a nutty idea I had a the time. His words were.....are you building a boat or a torpedo?

Guys often get pissed when I suggest they are putting too much into small boats but it seems to happen all the time.

Now maybe this isn't the case for you. Not trying to be a weeny. Not being able to get enough foam in to offset the sum of your parts suggest this may/might/possibly be the case.

It was for me. There wasn't room for jack squat in there. My setup didn't run worth a crap fortunately. I gave up on it before I lost anything. Think Chris might have said "I told ya so!" He would totally do that too.

A 29" boat with anything over a limited setup in it would be tough to keep at the surface. Especially a mono. Seems like I get no time to snag em'.

[Froggy]

Let?s sum up all this theory with a fool proof way to ensure we have enough flotation. In our boats.

Do we weigh our boats, vacuum pack what we think is the correct o amount of floatation in a bag with led shot that equals the weight of the boat and toss it in the bath tub ???

[T.S.Davis]

Why aren't us high schoolers discussing density at all? Did they not teach density in high school. I swear I remember that. It's why water......doesn't sink......in water.

Unless they are different temperatures of course.

[T.S.Davis]

It's density.

If your boat and it's foam are less dense than the surrounding water it will be at or near the surface. If it's not, call the diver. He'll be wearing lead to make him more dense than the water.

[Panther6834]

It's density.

If your boat and it's foam are less dense than the surrounding water it will be at or near the surface. If it's not, call the diver. He'll be wearing lead to make him more dense than the water.

EXACTLY what I've been trying to explain to Froggy & Silver954...but, neither seems, or wants, to comprehend. It's a simple...VERY simply...law of physics.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

[NativePaul]

Maybe its easier for us that use metric, 1 liter is a 10cm cube and it displaces 1kg of water.

[Silver954]

EXACTLY what I've been trying to explain to Froggy & Silver954...but, neither seems, or wants, to comprehend. It's a simple...VERY simply...law of physics.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

I am not sure what's being explained to me, since I didn't have any questions.
I have managed to keep the hobby off the bottom of lakes, so keep the man-splaining to yourself.
I have read the forum over the years and Panther you are the keyboard warrior that needs another hobby.
Peace ✌️

[Silver954]

To be perfectly clear it's always a displeasure to read anything from you Panther6834. You sound like a very square person.
So when you see my username feel free not to comment or mention me. If you saw me in person you'd understand what you can say and not say.

I don't personally read your comments in most threads. So if you were man-splaining to me, I see where you thought I cared what you had to say. But no....I never read your comments.

[T.S.Davis]

So if you were man-splaining to me,

Yeah, sorry I do that a lot too. I must have a bunch of guys that just block my posts so they don't have to read them. I can't help myself. Plus, I type fast. I cause myself more trouble that way.

[Panther6834]

Yeah, sorry I do that a lot too. I must have a bunch of guys that just block my posts so they don't have to read them. I can't help myself. Plus, I type fast. I cause myself more trouble that way.

I believe he was referring to me...but, everything you said in reference to yourself could also easily be applied to me...lol.

I admit, I tend to sometimes be "overly wordy" in explaining things...but, most of the time, I'm doing such so that what I'm saying (hopefully) doesn't get misunderstood. At the same time, unfortunately, there are those individuals with little patience, and whom don't like reading more than 2-3 sentences. Maybe they get bored easily. Maybe they have ADD. Maybe they just don't like others pointing out that they're 'wrong' and/or don't like having things explained. Honestly, I don't know.

For those who take what's said, and learn from it, fantastic...and, to those who want to 'ignore', so be it, as that is their choice. I don't hold anything against them. If they want to hold things against me, that is also their choice...tho, at the same time, it also proves any 'negative' points I might have made in their direction.

Put another way, to each, their own...c'est la vie.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

[Racingjake]

I've been a certify Scuba diver for almost 40 years and it comes in handy. Plus a guy can never have too many hobbies.

Something like an air bag stuffed in the hull away from hot and moving parts might be an idea ?

[Panther6834]

I've been a certify Scuba diver for almost 40 years and it comes in handy. Plus a guy can never have too many hobbies.

Something like an air bag stuffed in the hull away from hot and moving parts might be an idea ?

If such could be permanently sealed (ie. no permeation/off-gassing of the air), and stuffed into the bow, that actually sounds like an excellent idea...essentially, a bow-shaped BCD. Even better, instead of being filled with air, having it filled with helium (lighter than air) would be even better. Seriously, I wonder why no one has thought of this before.

The only possible problem I see with this is finding a non-permeable material, or being able to utilize a small air-fill nozzle That wouldn't encroach the space needed by other things that would normally be placed close by (ie. batteries, motor, ESC, etc).


~ More peace, love, laughter, & kindness would make the world a MUCH better place

[Froggy]

I understand exactly what your saying mister,, what makes you think I’m not listening or don’t understand

[T.S.Davis]

Something like an air bag stuffed in the hull away from hot and moving parts might be an idea ?

I used to run with a guy that would put together a stirng of ping pong balls. He used shrink wrap like we use for batteries to tie them all together. Looked.......well........wrong.....but it did work. You're limited again by the shape but that air was staying in the ping pong balls for sure.

Just remembered this too. You can also use pipe insulation. Because it's smaller and a bit more flexible than noodles you can sometimes actually get more foam into a cavity. 5 pounds of crap in a 5 pound bag so to speak. With noodles you have to cut and trim and shave to get them to fit just right and even then you likely have a gap that could have had flotation. Another idea.

[Froggy]

Well folks today and persistence paid big dividends, I got my boat back, pictures show my buddy Joe who scooped it up with a 16 ft pool pole net.
Pool noodle floatation, the boat full of water with all hardware must have weighed at least 8lbs plus it was heavy.
saved the motor that?s about it.
The stock large cat pack on the ESC one of the Caps broke off from corrosion, the servo, and receiver are shot also but I got her back I?m so thankful,
I spent 10hrs trying to get her back, persistence, no more poodles for me they didn?t even come close to floating this boat

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[Gary]

I ALWAYS use spray foam....try it !! Fills every void in the nose and sides or wherever so that water has nowhere to accumulate in those areas. Plus helps big time with major crashes that can damage the hull...foam helps keeps her together !!