Pod flotation

[dnej]

I have a pod , made up of 3 sections.

Two of the sections are sealed, around 80 litres each.

The middle one, with the inspection hatch, is also sealed, with a false bottom for drainage, from the main hull.I fell this should be foam filled ( close cell)

My question is, should I put inspection hatches on the other sealed units, and fill them all with closed cell foam, which would mean I would have flotation, regardless of damage to the pods, which could cause them to leak.

What is your opinion of the PVC hatches.?
David

[Blackened]

G'day

Honestly, If they're sealed now.......... leave them that way. If you were to do a spin out/inspection hatch, have a look at the ones they're putting on the 2400kc's on their pods. It's a one piece and seems to seal very very well. I'd prefer these to the traditional 2 piece ones.

Dave

[Roughasguts]

I guess you could put a drain bung in the bottom of the sealed pods, just to see if they do collect water.
Personally I wouldn't have a pvc inspection hatch cause that will end up the weak spot and maybe prone to leak, or crack.

[dnej]

I think boats in survey have better inspection hatches.

I need the inspection hatch of course, to access the motor mounts.

My thoughts are, that once a pod is holed, without internal flotation,it becomes useless.Filled with close cell foam, the flotation aspect would still work.
David

[Chimo]

Hi David

How much extra lift of the bum did you get with all that added, or are you still to wet it?

Personally, IMHO I'd put the best spin out a la KC2400 as suggested by Dave in the centre so you work the mounting nuts and leave the other two, which I see are independant as they are ie intact.

Did your welder pipe the bung hole outlets on the original transom to new outlets on the arse of the pod so it stays dry and all the bilge water flows past without wetting the insides of the pod?

The chances of punching a hole in either one is very slight and as a fellow GOM your not likely to punch a hole in the boat either as your not into riding rapids are you? I see you have (or seem to have a little extra freeboard too.

Cheers
Chimo

[dnej]

Chimo,
I value your comments.
Have had the unit done for about 3 years now. Well and truely been wet.

We removed the well, and added the centre pod.The other two were originally on either sde of the motor.
The centre pod is not piped, as such, its open,but has an false floor, to allow the exit of the bilge water.

So it is sealed, above.
The centre pod has two bungs, just in case, so I might just do the centre one with the cell foam.
David

[dnej]

Double post oops
David

[Chimo]

? No pic David
C

[dnej]

Try this one
David

[Chimo]

Interesting, is the fitting at the bottom for the starter handle? Three bungs, did you reckon she was going to leak a bit?

With the amount of lift from the pods / fixed trim tabs (with sealed tops) not sure that I'd bother with foam. If your worried about water in the boat what about a decent sized bilge pump on a float switch for when you do you bar crossings?

Looks like that if you do stuff some non soak up water foam in the centre you can still get the mounting nuts.

Chimo

[rubba]

if you have bung in bottom you will need breather other wise it will suck water in rgards rubba

[Blackened]

G'day

Have you considered a stainless version of the infamous inspection port?

Dave

[dnej]

Dave, are they available?Must have a look around.

Rubba, the bungs are in a tunnel,not part of the pod, they drain directly from the bilge.
Chimo,
I like to give the old girl a good tub out when I get home.Bungs allow for excellent cleaning. Stern area is accessible, by lifting a hatch in the floor.
Crank handle ( LOL)
that is the support for the motor bracket, instead of being on the trailer, it forms part of the stern. Great idea. No flex at all.
Have two bilge pumps, but they dont work when a battery is submerged.

I am talking about emergency flotation here. What does your boat have, in the way of flotation, in an emergency
David

[ShaneJ]

Hi David, do you mind if I ask who did the work on the pod? And how many dollars it cost roughly?

Thanks mate

[Blackened]

G'day

Yes they are avail. Not too sure where from however a search of the major retailers should turn something up

Dave

[dnej]

Shane, was an overall cost, including a new plate bottom fit, so I dont know how much for the pod. The two originals were $500, but that was 5 years prior. Fisher boats did the last one.
David

[Chimo]

Hi David

Re floatation
A 6.2 m Vagabond has a sealed (apart from the bung) section on each side of the fuel and water tanks under the deck.

And "there are a number of fenders that need to be tied on appropriately so when its upside down with its bum pointing at the bottom the bow will break the surface occasionally so someone can get a line onto it"

Seriously though has anyone seen what a Vagabond does when it sinks with a couple of 115HP motors on the transom and 4 batteries snuggling up against the transom? Boatboy 50 are you there?

Cheers
Chimo

[dnej]

Chimo, I dont think he heard you(LOL)
The two smaller pods on mine,are supposed to support 80 kg each, so they tell me.Guess the centre section would do the same.
I only have one motor, 122kg, and two batteries. So it would go a long way to helping out, so long as they were not holed.
David

[gofishin]

..., so I might just do the centre one with the cell foam.
David

...I am talking about emergency flotation here. ...
David, if you are thinking about extra flotation foam for an emergency situation I would be just looking at flotation in the outer pods, as this will give you significantly better swamped stability. Flotation in the centre of the hull should be avoided if you can help it.

You could get it foamed in-situ, but be weary as the installer will need to know what they are doing. Pressures generated by expanding PU can be as much as 12psi from memory. There is also the issue (with foamed in-situ) of what do you do if there is a small leak over time in a concealed compartment (corrosion).

Maybe look at good quality inspection hatches as suggested and block PU foam (coated in resin if you are pedantic). Obviously you will need quite a few smaller blocks. Can you put hatches through the old lower transom into the pod outers, ie. in the vertical with access from within the boat? Maybe too small an area. Otherwise in the duckboard, but sealing against checkerplate might be a job that needs re-doing every so often. Otherwise custom chk-plt hatches on welded raised flanges, tapped & flange sealed - but maybe exy & overkill hey!
cheers

[dnej]

David, if you are thinking about extra flotation foam for an emergency situation I would be just looking at flotation in the outer pods, as this will give you significantly better swamped stability. Flotation in the centre of the hull should be avoided if you can help it.
That is a good thought, although unless holed in some way, the centre pod would be water tight as well

Maybe look at good quality inspection hatches as suggested and block PU foam (coated in resin if you are pedantic). Obviously you will need quite a few smaller blocks. Can you put hatches through the old lower transom into the pod outers, ie. In the vertical with access from within the boat? Maybe too small an area. Otherwise in the duckboard, but sealing against checkerplate might be a job that needs re-doing every so often. Otherwise custom chk-plt hatches on welded raised flanges, tapped & flange sealed - but maybe exy & overkill hey!

I would use the closed cell foam, that doesn't hold the water.Vertical access, would be nice, but out of the question, as there is now a built in tray right across, internally.
The manufactured ss hatches, or aluminium, off the shelf are very pricey as well. I just dont know how good the PVC ones are.Maybe overtime, I will replace them with SS or aluminium. Thanks for the other ideas.I have seen that on plate boats, with extended transoms
Thanks David

[boatboy50]

Hi David

Re floatation
A 6.2 m Vagabond has a sealed (apart from the bung) section on each side of the fuel and water tanks under the deck.

And "there are a number of fenders that need to be tied on appropriately so when its upside down with its bum pointing at the bottom the bow will break the surface occasionally so someone can get a line onto it"

Seriously though has anyone seen what a Vagabond does when it sinks with a couple of 115HP motors on the transom and 4 batteries snuggling up against the transom? Boatboy 50 are you there?

Cheers
Chimo

Pete,

I've never seen a Vag the wrong way up. They are built too well for that to happen, and quality control at the factory did a great job! It would definately float with the nose out for a while, before finally giving in to gravity and going down.

I've seen plenty of boats full of water in my VMR time, and only a handful of those have sunk totally when attended to within the first few hours.

The voids under the floor, bunks, air in the cabin ect does a great job to hold them up, if only for a short term period.

I podded my first boat, a Seafarer Venus, and had no floatation in the pod, just a bung at the bottom and a plastic inspection hatch at the top. The inspection hatch was about 10" above the waterline most times, and I never got water in it from memory.

I personally would not use foam, as every waterproof foam I have known (even survey required) has soaked in the water after a while, and became a dead weight to the detriment of the boat and it's performance.

The chances of holing a pod is very small. I'd be more concerned about holing the bow and the pod being the only section not full of water.

Regards

Darren

[Chimo]

Thanks BB50 especially comforting to know about the quality control and that I have some time it would seem; to tie the fenders onto the stern to get the most benefit, not that its ever going to happen anyhoo.

Went thru the bar the other day (2m plus about 1.7 on top) and it just did go "thru" it. Boy it can throw some water when the tabs are half way down and you spin the props and it gets its mind made up.

Cheers
Chimo

[dnej]

Darren,
Thanks for the knowledge.I thought the closed cell foam wasn't supposed to suck up water.
Is that incorrect? Would like to know more, as I was also considering changing the existing bunk material , to closed cell foam.
Regards David

[dnej]

I have done some more research on the closed cell foam.

Every thing I read says that this foam does not soak up moisture. Does anyone know any different. Thanks
David ,