Hull Floatation

wetwhopper · #26

I have 2 fairly large deck storage compartments w/ hinged hatches. I mostly use the forward one for fender storage and I leave the rear compartment empty for easy access to my bilge (soon to be bilges). Will have to measure exact dimensions soon, but wonder if there is some type of blocked foam that would give me some floatation that I could just pull out and replace randomly My forward hatch has welded walls on all sides, while my rear hatch is open to water running to the bilge.

The only prob is all my floatation would be pretty much running down the center of my hull.

#27

I have been told that many commercial boats fill their below deck voids with empty soda and water bottles with the caps screwed back on to create cheap and functional flotation.
I would like to hear any thoughts on that subject. How many empty gallon jugs would you need to compensate for the weight of the boat, motor, gear, and crew??

MacCTD · #28

wetwhopper wrote:I have 2 fairly large deck storage compartments w/ hinged hatches. I mostly use the forward one for fender storage and I leave the rear compartment empty for easy access to my bilge (soon to be bilges). Will have to measure exact dimensions soon, but wonder if there is some type of blocked foam that would give me some floatation that I could just pull out and replace randomly My forward hatch has welded walls on all sides, while my rear hatch is open to water running to the bilge. The only prob is all my floatation would be pretty much running down the center of my hull.

Workskiff uses block foam in their boats, maybe give them a call, http://www.workskiff.com/

Katoh · #29

S L Dave wrote:I have been told that many commercial boats fill their below deck voids with empty soda and water bottles with the caps screwed back on to create cheap and functional flotation.

well our last boat took 15 cartons of beer to fill lucky we were still in dry dry dock some 160km from the coast as we forgot to put the lids back on so lucky we did not sink in our own dribble that night, Maybe!
I apologise could not help what I just wrote, it was just left wide open.
On serous note, I have heard of the same practice, although what I am let to believe a lot of these containers brake down rapidly in a salt water environment. A bit hard to believe but maybe so. I have played around with Biodiesel and in the early days I use to experiment with it in PET bottles (Soda Bottles Plastic), some of these have had a mixtures of very corrosive and harmful chemicals in them for at least 10 years and still look like the day they were bought. Maybe fill your hull with PET bottles, no corrosion, no foam little weight and max buoyancy, but remember to screw the lids on.

Katoh
In case you want to search PET Bottle
http://en.wikipedia.org/wiki/Polyethylene_terephthalate

#30

If you use the block foam keep a eye on it as GAS and DIESEL will MELT it to a goo down in your hull and it BURNS very well .
I wlike the PET bottle idea and it's cheap.
Each gallon bottle will float about 8 pounds . A cubic foot holds 7.4 gallons, just do the math. And of course 2 bilge pumps NEVER hurt anything.

http://www.youtube.com/user/BLM26CC · #31

S L Dave wrote:I have been told that many commercial boats fill their below deck voids with empty soda and water bottles with the caps screwed back on to create cheap and functional flotation.
I would like to hear any thoughts on that subject. How many empty gallon jugs would you need to compensate for the weight of the boat, motor, gear, and crew??

On that same note:

Saw a guy in a magazine (crazy Louisiana Sportsman magazine....my favorite read!!) That had a bass boat with a monster jackplate on it with a huge setback to it.

He "claimed" that the TWO inflated Volleyballs he had stuffed between the transom and inside the jackplates void helped to keep water from pouring over his bass deck when he came off plane really fast. (IE: Bass boats have no free board!), versus

So, Curious George,

You could always fill the hatches you have with Volleyballs versus all that good stuff, like PFD's, tool kits, gaffs, bag'O sinkers, and such......

Damn, I really wouldn't worry about it. Ya don't even have 100 hrs on the boat yet. Let us all know after your first 100 hrs.

wetwhopper · #32

Thanks for all the great input (even yours jettywolf... got ya!). "SEMPER PERATUS BABY!!! I seen a boat the other day that got 5' pool noodles @ the dollar store and bundled them under his gunnels and below deck, Lol! I'm just wondering what happens when I'm running hard for fish and I hit a big'ol cedar tree floating in the bay. I would like to think it would just put a big dent in my bow, but????

#33

What about the material that the white water rafts are made out of. I know that stuff is RUGGED. I imagine it could be made to shape. I look at it like this: Inflate for flotation purposes. Deflate it if that area of the boat needs to be worked on, mods, repairs ect. Just a thought....

#34

The one problem with the raft stuff would be cost. You would need the material and patterns made and then assemble /glue them together. otherwise it is a good idea

http://www.youtube.com/user/BLM26CC · #35

wetwhopper wrote:Thanks for all the great input (even yours jettywolf... got ya!). "SEMPER PERATUS BABY!!! I seen a boat the other day that got 5' pool noodles @ the dollar store and bundled them under his gunnels and below deck, Lol! I'm just wondering what happens when I'm running hard for fish and I hit a big'ol cedar tree floating in the bay. I would like to think it would just put a big dent in my bow, but????

My god this topic will NEVER END!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

So, on that note. My ole Glass boat I had before the mega-awesome Jettywolf. Had 2" X 4" X 6' foam boards sandwiched between the hull and under-deck. Gave room for condensation to make it's way back to the stern bilge area. Like the BIG BAD Jettywolf, the deck was all one piece. No hatches, no nuthing, just one inspection plate that of course always leaked, kinda like an Armstrong Compression deck plate.

(that I got rid of care of WelderBob, fellow AAB brothern and added a thick alloy plate, instead 5200, and painted over 4 times, now no mo' leaking thru.)

So pool noodles may seem funny, but I had their "cousins" under my deck.

Curious George, jus' show us yer shiney new Shark hide j-o-b, and some OTW - "on the water" time.

drookit · #36

I thought the transom saver topic was the one that would never end.

NTGeorge · #37

Hey Guys
I'm not 100% on what the ruling is over there with hull lengths and mandatory foam instillation but over here anything 6m and under it's compulsory. I personally still install foam in all hulls that I make regardless of size. If you don't mind a little reading then there is a disturbing read about a boat that went down over here and all on board died. For those that don't like to read the end result was it didn't have foam installed, bad weather hit, they sunk, they died. Sad Day.

Do a search on google for "Malu Sara", there are two reports, you want the coroner's report.

Over here pool noodles are made out of the right stuff, people that want to put foam into their hulls go get pool noodles, cut the into sections and place them longitudinally between frames. The trick is to place them in this way so if you get water into the hull the water will drain out the end of the noodle when the jockey wheel is wound up. Problems only really start to occur when water is trapped around/in/under the foam.

hope this helps

Cheers

Katoh · #38

Gentlemen
Ever since reading this post i have been looking further and further into the subject of floatation, and the more I prod and probe my hull the less certain I am that there is any there.
Now this brings me to a question, the question being of an existing hull with fully welded self draining deck, how do you get the floatation under it without major works and what sort to use. I have one only access point to the hull through a sealed 4" hole in the fuel well, not much access there to feed in foam , noodles, PET bottles, but may have one other solution Ping Pong Balls, can be pumped in using compressed air. Only a few problem's now, there not fuel tolerant they are highly flammable and after a while they create static charges.
The other option again is 50mm or 2" polyethylene balls, stable, non dilutable in fuel and quite tough, the only thing is hope you never have a hull breach more than 2" in diameter as they will just pop out escaping and expect a fine from the EPA for releasing 10-15000 odd plastic balls into the ocean. Mind you it would be pretty hard to put a 2" puncture into a 5mm aluminium plate in a 20' boat.

Katoh

wetwhopper · #39

Cut out your deck, apply desired floatation material, patch the deck, pressurize= airtight deck with floatation. good as new. I don't know what I'm talking about, but I don't see any reason why it couldn't be done? Talk to your hull's manufacturer 1st (I guess). I've seen aluminum decks cut and fabricated on, then patched, sanded and painted to the point that you can't tell there was ever work done to the deck. Good luck with your quest.

#40

Get a life raft packed in a canister and party on.

#41

welder wrote:Get a life raft packed in a canister and party on.

Your boat was built without it and so grandfathered in. You have insurance to cover the boat. Life raft is your insurance to get you and yours home safe.

Katoh · #42

welder wrote:Get a life raft packed in a canister and party on.

goatram wrote:Your boat was built without it and so grandfathered in. You have insurance to cover the boat. Life raft is your insurance to get you and yours home safe.

Re: Hull Floatation

Gentlemen that is probably the wisest words of wisdom I have heard in a long time, many thanks, we tend to get caught up with one issue and fail to see the whole picture surrounding us.
Cheers
Katoh

pjay9 · #43

Here is a thread to look at: viewtopic.php?f=4&t=2624 Capt PJ

pjay9 · #44

And another: viewtopic.php?f=3&t=2451 Capt PJ

pjay9 · #45

Pool noodles will be going on sale soon! End of summer sales at pool shops and many on line stores! Just a thought! Capt PJ

Katoh · #46

Capt PJ
Really good reference's to the the threads, and educational reading. I am trying to get hold of the builder, to ask what exactly is in the hull, Ill see how that all ends up. The poodle noodle's are looking good at the moment, but tossing up if I should just put it back the way it was. I still have plenty of time to think about this, and hopefully I will get some answers soon to my questions.
Cheers

Katoh

CTMD · #47

Katoh, what brand of boat do you have? Drop me an email chris(at)ctmd.com.au and I'll put you in touch with some more cost effective suppliers of foam. First point of call would be specmar Australia.

Katoh · #48

CTMD
Thanks I have sent you an E-mail.
Cheers

Katoh

drookit · #49

Anybody remember the Mythbuster's episode where they used ping pong balls to raise a sunken boat?

Ken

Katoh · #50

Yes I remember that episode, and even looked into using them as floatation, but we have a few dramas with that. Firstly they are highly flammable, and second they build up static charges when rubbed up against each other, the last is they deteriorate when in contact with fuel. Those three things you don't want in your bilge. I looked into Polyethylene balls the same size a little heavier, but the pricing will kill me. I was quoted 11c each but you need 11000/per cubic meter which is only a capacity minus voids of 750kg of air so double it 22000 balls for a 1.5 ton boat (metric) $2500 plus freight. I could put in 4 auto pumps for $300.
Cheers

Katoh