The importance of floatation

[RIPFENCE]

HI ALL,
HAD A DISASTEROUS DAY AT THE LAKE..I WAS TRYING OUT A NEW PROP AND FLIPPED MY DF29 AT LOW SPEED OVER BIG WAVES. MY HATCH TAPE WAS WET FROM A PREVIOUS RUN AND IT CAME OFF THE DF SANK TO THE BOTTOM IN 6.5 FEET OF 45 DEGREE WATER. I LOOKED REAL STUPID WITH MY RUBBER RAFT TRYING TO RECOVER MY BOAT OFF THE BOTTOM. TOOK 30 MINUTES..MY GPS STILL WORKS AND I AM DRYING OUT THE REST..FUNNY THING WAS I COULD STILL HEAR MY SERVO ADJUSTING AS I POURED THE WATER OUT OF THE HULL..I WILL NEVER HAVE A BOAT WITHOUT FLOTATION AGAIN..@#$%!^^^%#$%#:cursing::mad:

[Fluid]

Don't feel too bad - lots of folks have made the same mistake. Not only do you need some floatation, you need enough floatation. A good rule of thimb is to have 29 cubic inches of floatation for every pound of boat, minimum.





.

[RIPFENCE]

thanks for the good info..just another example of learning the hard way..i hope my neu 1515 is going to make it..as well as my lipo

[ozzie-crawl]

and always add some to the hatch as well

[jcald2000]

Spray the Nue inside with WD-40 ASAP[the magnet will rust!] and reoil the bearings. Works for me!

[RIPFENCE]

Awesome info..wd40 here i go...thanks a lot

[JimClark]

better off using corrsion X I would think.
Jim

[RIPFENCE]

funny you said that..i ordered some corrosion x yesterday and it will be a week before i get it though thank you

[BILL OXIDEAN]

Don't feel too bad - lots of folks have made the same mistake. Not only do you need some floatation, you need enough floatation. A good rule of thimb is to have 29 cubic inches of floatation for every pound of boat, minimum.





.

Wow! I was only coming on this thread to stress that very point, flotation can be your worst enemy if not done right. If you use too little flotation a number of dizasterous things can happen.

The worst scenario I've experienced is a boat that neither sinks or floats, but suspends itself mid depth and slowly drifts out to never never land as it could be ANYWHERE in the pond.

You have to make certain that you use more than enough to make her float, or you're better off running hollow as I do.

I like boats that sink fast if they're gonna do it, but that's only because my test pond is only 5ft at its deepest, and i've been trained in marking/sighting exactly where it went down. I also have a brand new wetsuit, so wading in cold water isn't a HUGE issue

Moral of the story, make certain you use enough

[RIPFENCE]

point well taken bill..i suppose there is. nothing worse tha a boat in limbo. i do enjoy letting my boats rip out in the middle of my test pond sometimes so i guess i should fill it with foam or pay the price..

[Efis]

but suspends itself mid depth

Wow.

Blake

[bwells]

Ripfence: I have noticed , as well, that the hockey tape looses it's stickiness after a short time of getting splashed. I was thinking of packing tape but have not tried it yet, not sure what it would do to decals. Any thoughts on expanding foam that will not distort the hull? I think I remember someone saying Great stuff but not sure.

[crabstick]

I lost a boat that split open and dumped its flotation for two years, a guy found it when looking for his hatch..

Since then I test the flotation of every boat I build, normally by trying to sink the boat in the bath (with dummy cells and motor etc) For reviving wet electronics try this, it sounds crazy, but I have revived quite a bit of wet gear using this method.

firstly disconnect any power sources at the earliest possible opportunity, remove any plastic casing from wet object, boil jug, pour boiling water into bowl, drop item in bowl for 5-10 sec. Remove from bowl, dry with hair drier, spray with either wd40 or corrosion X, leave in hot water cupboard or another warm place for about 24 hours, Test device.

Twas only a couple of months ago I kicked some saltwater into my futaba t6ex 2.4ghz, it started going nuts and the lcd was showing crazy stuff and I thought I was in for a new radio until i remembered the above method, 24 hours later it was running smooth again.. :banana::banana: my wife was happy too

[RIPFENCE]

now that is thourough testing!:laugh: as far as hockey:tape: goes i feel it works well as long as you do not try to use it for more than one run..they tape i am using is the stuff sold by ose..not like the fabric style..expanding foam may work as long as its marine grade..it does not look to good though..maybe i can make a chamber for the front to contain the foam..then there is always the water noodle cut into smaller noodles:bounce::bounce:

[exotica]

...good advice, ive used new noodle in mine. Now that Fluid has shared the magic numbers I might just recalculate how much ive used. I know my cat aint going to sink, even if it does fill up with water.

[Unsullied_Spy]

Definitely stuff it full of pool noodles, I sank my SuperVee a few months back and I had too much weight in it for the stock floatation to keep it up and it sank to the bottom. As we were recovering it we could still hear the motor beeping as the ESC waited for radio signal.

[CornelP]

Foam will not expand to break the hull, if it's the right one: do not use the standard sprays, but the ones adapted to a gun style dispenser. These will shoot the foam at a higher pressure and it will expand to 99% before even hitting the boat... I have used it a couple of times and it is perfect.
BTW, WD40 is slightly abrasive, so be careful with it on motors... very good water repellent, but moderate use...

http://www.home-is.co.uk/product_info.php?products_id=215

[Fluid]

I strongly recommend not using the NHP two-part expanding foam. I used in in a very stout 'glass sport hydro and it stiffened up the hull even more, acting as a structural part of the boat. But about a year later it started to shrink, pulling the deck down in a wavy pattern over 1/8" - so much that the hatch no longer fit. I had to cut it away from the deck, fortunately the deck popped back up most of the way. I prefer pool noodles anyway, that was an experiment - which failed.



BTW, WD40 is slightly abrasive, so be careful with it on motors... very good water repellent, but moderate use...
Abrasive - without solids? An odd property which I've never seen mentioned before.


.

[CornelP]

Well, this is what I was told by a guy that sells it. To be completely honest, it is due to its ability to "attract" any residues... and hold them there, especially if humidity or oil are present. In itself, it is NOT abrasive, being just a hygroscopic solvent.
Normal use: Water Dispersant (hence the name, recipe No. 40). It is also not a high wear lubricant, can only be used on light service. The best description is: very good short term lubricant, but so is water...

[BILL OXIDEAN]

Stick a roll of paper towels in the trunk of the car you go to the pond with.
THOROUGHLY dry the deck and hatch before re-taping

Sounds simple, but how many of us forget towels when we jaunt to the pond?

I find paper towels and napkins better than using cloth towels.
re-using cloth leaves a slight ammount of moisture on the mating surface deeming the tape useless in a 35+mph crash

[Doug Smock]

Whatever you use for floatation, consider using an adhesive to keep it in the hull in the event of a catostrophic hull failure. (It happens)
Not much worse than having your floatation simply mark the spot where your boat went down.

My .02
Doug

[BILL OXIDEAN]

Whatever you use for floatation, consider using an adhesive to keep it in the hull in the event of a catostrophic hull failure. (It happens)
Not much worse than having your floatation simply mark the spot where your boat went down.

My .02
Doug

Great point, and on that note, don't use double sided foam tape to secure it, it can have a tendancy to come undone when wet I used small dabs of epoxy

[Doug Smock]

Great point, and on that note, don't use double sided foam tape to secure it, it can have a tendancy to come undone when wet I used small dabs of epoxy

:iagree:
Gorilla Glue works well also, fills small gaps and is tough as nails!

[FloatDaBoat]

These photos are of what Great Stuff spray insulation foam looks like applied to the sponson tips of my cat during construction. It will stick to anything, so be sure to mask any areas where you don’t want it to. A word of caution: it continues to expand for days after being sprayed in. I had to sand it down three days running before attaching the deck, & it still expanded a little more - - causing a slight bulge in the deck. I wouldn’t recommend using it in an already enclosed space, as the hull/deck seams might split wide open.

[befu]

that is interesting about the long term shrinkage, thank you for pointing that out. i have used it in the past but never filling a hull. I was thinking about it, but will have to do some experimenting now. It is full of air, wonder if it is temperature and pressure sensitive?

Like many, I have damaged hulls by using the spray expanding foam in my early days.:doh: I still do use it at times, but you have to use it correctly. If you use spray foam, do not fill the cavity. I make sure that it does not fill the space from the bottom to the deck once expanded. it works fine, maybe even adding it in multiple segments. It helps to be building a house and use the remnants of a can from weather proofing.

The can spray foam will also shrink. I filled a hatch with it once, let it set for a few days and then trimmed it flush with the bottom of the hatch. next day, the old flat foam surface was concave! Didn't see that one coming.

Thanks for the knowledge fluid!

Brian



I strongly recommend not using the NHP two-part expanding foam. I used in in a very stout 'glass sport hydro and it stiffened up the hull even more, acting as a structural part of the boat. But about a year later it started to shrink, pulling the deck down in a wavy pattern over 1/8" - so much that the hatch no longer fit. I had to cut it away from the deck, fortunately the deck popped back up most of the way. I prefer pool noodles anyway, that was an experiment - which failed.



Abrasive - without solids? An odd property which I've never seen mentioned before.


.

[Chop]

These photos are of what Great Stuff spray insulation foam looks like applied to the sponson tips of my cat during construction. It will stick to anything, so be sure to mask any areas where you don’t want it to. A word of caution: it continues to expand for days after being sprayed in. I had to sand it down three days running before attaching the deck, & it still expanded a little more - - causing a slight bulge in the deck. I wouldn’t recommend using it in an already enclosed space, as the hull/deck seams might split wide open.

An alternative to "masking" is to spray or wipe a non-stick cooking spray to the surfaces that you don't want the foam to stick to. Then it is a simple matter of trimming the excess material away.

As an afterthought... You could just spray the entire insides with the cooking spray. You would have flotation molded to the inside of your hull. It might alleviate the "shrinkage" issue too (I hate that!).

[crabstick]

for boats that are "bouyancy challenged" such as some riggers where there is not enough space for the flotation needed to keep the boat bouyant I have thought of using a device such as :

http://www.marine-super-store.com/posit/shop/index.php?selectedpartno=99197216

They self inflate and can support 1kg, a couple of those might do the trick Embedded in the deck.

Theres this one also
http://www.shopwiki.com/Key+Buoy,+Self-inflating+Key+Ring



There is also another boaties keyring that has a cork and a huge length of braid in it, when it hits the water the keyring sinks, but the cork ejects and leaves a trail of braid to the ring which you simply pull the keyring back...

[egneg]

for boats that are "bouyancy challenged" such as some riggers where there is not enough space for the flotation needed to keep the boat bouyant I have thought of using a device such as :

http://www.marine-super-store.com/posit/shop/index.php?selectedpartno=99197216

They self inflate and can support 1kg, a couple of those might do the trick Embedded in the deck.

Theres this one also
http://www.shopwiki.com/Key+Buoy,+Self-inflating+Key+Ring



There is also another boaties keyring that has a cork and a huge length of braid in it, when it hits the water the keyring sinks, but the cork ejects and leaves a trail of braid to the ring which you simply pull the keyring back...


Starting to look like a 007 movie with all the gadgets. :buttrock: