Re Ballast after Pumpout removal

[SandyD]

Hi,

 

Having had the (very Rotten) pump out tank removed from our boat and replaced with a cassette toilet we have noticed a slight list due to the lack of weight on that side - most noticible in that the shower does not drain to the plughole anymore.

 

The tank was on the floor boards and so the floor boards have not been lifted and I do not want to ripout the bed etc to get the floor lifted to play with the balast under the floor. I think that the removed tank must have weighed approx 160KG empty so I am proposing to stack concrete slabs/bricks or similar in the space left by the tank , ideally next to the side of the boat so that we can use the remaining space for storage. Does this sound reasonable? Any tips or better solutions?

 

 

[Tracy D'arth]

Steel billets are heavier and take up less space.

[David Mack]

You probably have less ballast on the side of the boat where the tank was. But that doesn't necessarily mean that there will be an open space in the bilges directly below where the tank was. So if you have no way of knowing where there is and isn't space for additional underfloor ballast, then adding some above the floor may be your best option, albeit that in some ways its a bit of a bodge.

As Tracy says, steel billets would be best - stack neatly and take up little room. Or 56lb cast iron weights if you can find some at a reasonable price.

Mann Buck sell steel ballast. Or look on ebay.

[Tony Brooks]

Probably difficult on many boats, but when I needed to trim for list I took down an internal hull lining, wrapped thick paving slabs in bubble wrap and placed them between the internal framing. before refitting the lining and ensuring it would retain the concrete during most collisions. That meant they were as close to the side of the hull as possible. No problems for about 15 years.

[BEngo]

A 160 kg pile of ballast above the floor will be  a magnet for condensation and this will in time rot the flooring.  At the very least stack your ballast on some builders 1000 gauge plastic membrane.  Ideally you would wrap the whole ballast in a vapour barrier.  Tony's bubble wrap is one way.

 

If using steel you could paint the blocks with anti-condensation paint.

 

N

[Jen-in-Wellies]

1 hour ago, SandyD said:

I think that the removed tank must have weighed approx 160KG empty so I am proposing to stack concrete slabs/bricks or similar in the space left by the tank , ideally next to the side of the boat so that we can use the remaining space for storage. Does this sound reasonable? Any tips or better solutions?

The further away from the centre line of the boat the new ballast goes, the more effect it has on list. If the tank was the common arrangement of a 4' wide one under a bed that is against one wall, with a corridor down the other, then only 2' of it was away from the centre line. The other 2' was balanced around the centre line. You'd therefore only need 80kg to compensate for the tanks removal. 80kg is coincidentally a typical weight for a human, so if there is some one around that weight available, stand them about 1' from the wall, with the observer on the centre line and see if it corrects the list.

 

I moved the house batteries from one side of the engine hole to the other to correct a marked list on my boat. Used 25kg coal sacks to experiment first, before making the move, as they are a similar weight to a single 110Ahr lead/acid battery.

Jen

Think of your boat as being a bit like a seesaw in side to side list. Balancing it out involves both the amount of weight and how far it is from the centre pivot point.

[Guest]

Our boat was 'trimmed' using railway track 'chairs' - so when we reduced the battery bank size and had to re-trim the boat I just moved some of these to the other side to compensate until the boat levelled side to side.

 

Is there anything you could similarly move?

[SandyD]

2 minutes ago, M_JG said:

Is there anything you could similarly move?

 

Not that I can think of....

[system 4-50]

Depleted uranium is better still.  There maybe some as scrap available in Ukraine...

[MtB]

2 hours ago, system 4-50 said:

Depleted uranium is better still.  There maybe some as scrap available in Ukraine...

 

Gold makes better ballast. Denser than uranium.

[IanD]

2 hours ago, MtB said:

 

Gold makes better ballast. Denser than uranium.

Osmium... 😉

[MtB]

17 minutes ago, IanD said:

Osmium... 😉

 

Yes a slightly higher SG but not so common as gold, and difficult to buy 160kg of it at a time, I suspect.

 

 

 

 

[IanD]

1 hour ago, MtB said:

 

Yes a slightly higher SG but not so common as gold, and difficult to buy 160kg of it at a time, I suspect.

 

Not difficult, just expensive -- 30x more than gold, 160kg would cost about £50M...

[Ken X]

Depleted Uranium worked for Boeing when counterweighting the early 747s. What could possibly go wrong. 🤔

[IanD]

Just now, Ken X said:

Depleted Uranium worked for Boeing when counterweighting the early 747s. What could possibly go wrong. 🤔

Nothing, because it's depleted. I've lifted a bar of DU up, and thought it was being held down to the bench with hidden magnets -- *ludicrously* heavy...

[MtB]

The other possibility is tungsten, with an SG almost the same as uranium IIRC.