Floatation

[devon007]

Hi Guys,

Started working on the new boat. Pulled up the marine ply to find this guy has crushed up old foam fruit boxes and put them under the floor......

Don't think this would have done anything?

Does it even need floatation?

Its a 5.4 mtr aluminium Bermuda runabout.

any advice?

Cheers

[antonywardle]

do the floor boards just pull up or do you have to undo them? If you have to undo them, then the polystyrene would help a little with floatation, noise reduction and insolation I'd guess As to whether you need flotation, I have no idea BTW, nice looking boat

Edited April 30, 2014 by antonywardle

[Juggs]

could also cause it to turn turtle depending on where you fit it

whats teh hull designed to do when swamped?
some will just fill up and float lvl with the surface,, which is preferable to a bottom full of foam which may turn it upside down and you have nothing to hold onto

[devon007]

hope this never happens. marine ply floor screws down so I think I am going to get some foam blocks from clark rubber and cut them to fit

[Guest Aussie007]

hope this never happens. marine ply floor screws down so I think I am going to get some foam blocks from clark rubber and cut them to fit

i think your better off with two part foam in tins mate, that foam from clarks rubber (polystyrene) holds water from what ive read or if u can afford it the foam i removed a few months ago from my tinny seat was similar to EPP foam expanded polypropylene i think its called

i would DEFIANTLY rather have floatation than have none at all, just think of all the possibilities in a bad situation without floatation and the recovery cost finding your boat and floating it than towing it back to the dock

weather the boats up-right or upside down it still gives u something to cling onto u can still hold onto the grab rails or bow and engine, u could even let kids in a situation like this climb up on the over turned hull for safety

[NaClH2OK9]

I looked into this briefly when I brought my boat. I considered expanding / 2 pack foam but found a few videos showing it can become water logged if it gets wet. Also if it goes under floor it will stop any water making its way to the back of the boat. Drain plugs. In the end I've not bothered yet but would think polystyrene bats are the most sutible.

......... SaltWaterDog

[macmac]

hope this never happens. marine ply floor screws down so I think I am going to get some foam blocks from clark rubber and cut them to fit

Hi Gappy,

I went to Aus-thyrene to get my foam when I had accidentally spilled the petrol inside the boat. They got a lot of off-cut there. Last time I just paid them $20.00 for a half load of ute. It is located in Kings park near Blacktown. i found out there are different types of polystyrene they got. Some of them are more firm and some of them are soft. Cheers Phil

[devon007]

Thanks Phil I will give them a try

[Juggs]

wrap them in plastic of some sort otherwise the foam gets sand and salt water between it and the aluminium
get salt etching for the aluminum quite quickly if you dont wash it out thoroughly

[cameldownunder]

My boat only has the sides filled with foam. I dount it will keep the boat out completely out of water, but I might be able to pump the water out. No foam under the floor. You loose some storage space, as tradeoff for ( mainly ) better noise insulation

[Billy2014]

Hi Guys,

Started working on the new boat. Pulled up the marine ply to find this guy has crushed up old foam fruit boxes and put them under the floor......

Don't think this would have done anything?

Does it even need floatation?

Its a 5.4 mtr aluminium Bermuda runabout.

any advice?

2005 bermuda.jpg

Cheers

G'Day,

I did a bit of research on this and I am pretty sure that under 6m, you are required to have basic floatation i.e, the boat may flip upside-down but won't sink down to the abyss, just bob around. Level floatation is also a bit misleading, it's supposed to keep the boat upright if swamped but manufacturers don't test this offshore in a swell, only in calm bays. I built my tinnie and as part of the design I was required to install 1.25m3 of foam under the deck for 'basic' floatation and I will at a later date, install some more foam under the gunwales to try and achieve an even better result. The best foam to use is closed-cell polyethylene boards, flexible, easy to cut and fuel resistant. Expandable foam isn't so great for aluminium as it can cause a reaction with the metal and pre-mature corrosion. In a boat the size of yours I would only be guessing around 1.1m3 of foam if you can get access or at least as much as you can get in and the amount required by standards depends on the weight of the whole rig with people in it. Better to be safe than sorry, once swamped, scuppers, drain pipes, gaps can fill with water quickly and sink a boat if the water isn't removed with scuppers underway or a bilge pump so at least with the foam you have a bit more peace of mind.

Cheers,

Bill.

Edited May 28, 2014 by Billy2014