Hull foam filling

[azzurro]

Hi all,

I'm new in this Sub-Forum, as I currently own a SIB.

I'm considering to purchase a Valiant Sport RIB. I have read that you can order it having the hull filled with polyestirene for extra floating.
I guess this is to avoid getting the hull filled with water in case you have a crack.
I've seen a moored RIB with the floats unglued apart in just one night. Hull and engine went to the bottom, because of this problem. Floats remained tied to the moore...

Any opinions on this filling?

[jyasaki]

Foam tends to hold water - if not within the foam itself, in the spaces around the foam.

RIB hulls will float on their own, so unless you have some instance where the hull is compromised, it shouldn't go anywhere.

Think about how many RIB's you've seen: Does one instance of an accident justify the necessity of foam filling? I wouldn't think so, but maybe that's just me.

jky

[azzurro]

Originally Posted by jyasaki

Foam tends to hold water - if not within the foam itself, in the spaces around the foam.

RIB hulls will float on their own, so unless you have some instance where the hull is compromised, it shouldn't go anywhere.

Think about how many RIB's you've seen: Does one instance of an accident justify the necessity of foam filling? I wouldn't think so, but maybe that's just me.

jky

I see. So, maybe a good idea in extreme condition ribs such as rescue boats (better floating than sinking) , but not in a summer beach rib.

Thanks for your thoughts jyasaki.

[Peter_C]

Closed cell foam is commonly used in most every smaller hard boat built today, at least in the USA. Sinking to the bottom today in a small boat is not acceptable, as they should float enough to keep the hull at the surface, but they will often turtle. The foam can still absorb water if constantly flooded but it takes years and years to saturate, and will still work even then to some degree just by keeping the entire cavity from flooding. Foam works excellent in boats as a dampener, and will help the hull keep it's shape (One boat manufacturer touted this saying it helped keep gel coat cracks down, but that could well be marketing). As mentioned above though a RIB is different in that the tubes provide floatation, and a RIB going to the bottom is so rare that is the first time I have heard of one. Must have been some Chinese junk to have the tubes fall off. Simple solution is to buy a quality boat, not a piece of junk.

Some manufacturers definitely tout foam as a benefit

[beerbelly]

last year at clachtol one of our party in a rib had a tube that after 3-4 hours was barely half inflated he still went out and had no problems he said the tubes are fastened to a boat as long as it doesn't get too rough ill be fine and he was. sometimes coming in with one tube totally deflated

[Starovich]

I've had bad experiences with dory's similar to the photo, we had a small crack in the hull over time the water seeped in.
Went back to the boat on the mooring it wouldn't plane, way to heavy,pulled the boat out of the water and the trailer punched holes in the boat with all the extra weight.

[azzurro]

Originally Posted by Peter_C

Closed cell foam is commonly used in most every smaller hard boat built today, at least in the USA. Sinking to the bottom today in a small boat is not acceptable, as they should float enough to keep the hull at the surface, but they will often turtle. The foam can still absorb water if constantly flooded but it takes years and years to saturate, and will still work even then to some degree just by keeping the entire cavity from flooding. Foam works excellent in boats as a dampener, and will help the hull keep it's shape (One boat manufacturer touted this saying it helped keep gel coat cracks down, but that could well be marketing). As mentioned above though a RIB is different in that the tubes provide floatation, and a RIB going to the bottom is so rare that is the first time I have heard of one. Must have been some Chinese junk to have the tubes fall off. Simple solution is to buy a quality boat, not a piece of junk.

Some manufacturers definitely tout foam as a benefit

"Must have been some Chinese junk to have the tubes fall off. Simple solution is to buy a quality boat, not a piece of junk."
Nope. Won't say the manufacturer but it was a main one. And...no rough seas.
It was not the tubes what fell off: it was the hull.

[Peter_C]

Originally Posted by azzurro

And...no rough seas.
It was not the tubes what fell off: it was the hull.

Now I am confused. The tubes attach to the hull, so did the hull break in two and leave part of itself attached to the tubes? Was it a fiberglass failure?

Either way the tubes were still floating so technically the boat was still floating above the water

[9D280]

I nearly killed myself trying to drag a waterlogged dory up a beach.

Closed cell foam is a good theory.

In Practice I would be a little more wary.

[A1an]

A little story for you...

Recently a lad round here thought it would be good to fill the hull of his Pioneer tender with expanding foam, he duly emptied several can into the hull via pre drilled holes on the deck, after the foam had expanded he plastic welded the holes, unfortunately both him and his boat were blown clean out of the water when the blow torch he used for welding ignited the trapped fumes in the hull.

The left over bits of the boat are lying on the shore here. You would think a hand grenade had been dropped in it. Luckily only the lads pride was hurt.

[HughN]

Originally Posted by A1an

A little story for you...

Recently a lad round here thought it would be good to fill the hull of his Pioneer tender with expanding foam, he duly emptied several can into the hull via pre drilled holes on the deck, after the foam had expanded he plastic welded the holes, unfortunately both him and his boat were blown clean out of the water when the blow torch he used for welding ignited the trapped fumes in the hull.

The left over bits of the boat are lying on the shore here. You would think a hand grenade had been dropped in it. Luckily only the lads pride was hurt.

I thought that was going to end with a picture of a huge pile of expanded foam with bits of boat sticking to it!

[Maximus]

Originally Posted by A1an

A little story for you...

Recently a lad round here thought it would be good to fill the hull of his Pioneer tender with expanding foam, he duly emptied several can into the hull via pre drilled holes on the deck, after the foam had expanded he plastic welded the holes, unfortunately both him and his boat were blown clean out of the water when the blow torch he used for welding ignited the trapped fumes in the hull.

The left over bits of the boat are lying on the shore here. You would think a hand grenade had been dropped in it. Luckily only the lads pride was hurt.

BLIMEY Nice!
I think the main reason some manufacturers inject Foam is because it's a cheap way to reinforce/stabilise and add rigidity to what is often a pretty light layup in the first place
Like most Cheap Fixes...best avoided!

[wavelength]

would avoid foam like the plague! We have cut the decks out of so many boats in our boat club to remove water logged " closed cell" foam that we are getting quite good at it. Get a few guys on the deck in a choppy sea compressing the foam underneath and it breaks down and soaks up every bit of water it can find. Don't go there.

[willk]

Originally Posted by wavelength

would avoid foam like the plague!

That said, judging by the photo, I'd say Boston Wailer may be using the right technique.

I mean with the chainsaw - obviously

[Poly]

Originally Posted by A1an

A little story for you...

Recently a lad round here thought it would be good to fill the hull of his Pioneer tender with expanding foam, he duly emptied several can into the hull via pre drilled holes on the deck, after the foam had expanded he plastic welded the holes, unfortunately both him and his boat were blown clean out of the water when the blow torch he used for welding ignited the trapped fumes in the hull.

The left over bits of the boat are lying on the shore here. You would think a hand grenade had been dropped in it. Luckily only the lads pride was hurt.

Oh yes, those fumes can prove costly if they go up...

[Maximus]

Originally Posted by willk

That said, judging by the photo, I'd say Boston Wailer may be using the right technique.

I mean with the chainsaw - obviously

Duh.... OBVIOUSLY!!
Maybe it's a Half Share Boat???

[azzurro]

Originally Posted by Peter_C

Now I am confused. The tubes attach to the hull, so did the hull break in two and leave part of itself attached to the tubes? Was it a fiberglass failure?

Either way the tubes were still floating so technically the boat was still floating above the water

It was a 6 or 6,5m rib used for diving.
The hull must have had a crack and water came inside so it lost it buoyancy.
The glue was obviously starting to fail, it was PVC floats with all of the Mediterranean sun 6 months a year.
The engine was 120hp (I mean, rather heavy).
Hull and engine and bow unglued away in one single piece while floats remained tied to the mooring buoy.

All in one night.