Lateral Ballast

[Rhod72]

This appears to be lateral ballast in My Jeanneau Sun Odyssey 342. It is situated just in front of the chart table and the phot is taken through the hatch in the settee back. It appears to be glassed in above. I'm not sure how it is secured below. The hot water heater is immediately inboard below so if it is secured from below access is going to be painful and difficult. I was thinking about removing it and replacing it with AGM batteries of similar weight that would feed radio and AIS and provide a degree of redundancy to the house batteries as well as pushing up the house bank to >500Ah.
I was was wondering if anyone has come across this before or attempted this before. Frankly I'm surprised lateral ballast is required to counteract the fridge and oven. I can't see the rear water tank and fuel tank leading to that much of a moment of inertia to justify this.
I don't want to start cutting it out only to have to fail and reglass it because I really don't want it coming loose whilst under way.

[tkeithlu]

Maybe we need more pictures. I don't see the "glassed in" part. I think I'm seeing a block of something that looks heavy sitting on a shelf. It looks reasonably removable.

Consider proceeding with removing it. If that goes well, then it will also be reasonably easy to return if you decide to back out of the project.

I'm all in favor of a separable addition to the house battery bank. I keep one lonely size 24 behind the instrument panel with a rotary switch. Normally it's part of the house bank, but it can power the panel separate from those batteries. The reason is simple - house batteries sit at the lowest position available. So, you take on water and need help. You pick up the radio microphone and guess what? The batteries have been flooded with seawater. No radio, and now add in an electrical fire in the bilge.

[Manateeman]

The Green Frog ...spot on again ! A lot of commercial vessels have a battery dedicated to radio and sometimes AIS and a medical phone. I’m not sure it’s a Coast Guard requirement but it’s a simple addition that makes a lot of sense.
All the new and large oil field vessels have this additional battery.
One of the advantages of a manatee crew of course is added weight where required. It takes several hundred frogs to equal the portable ballast of a single manatee. They have large paddles and the power to push a good size vessel in case of engine failure. Their daily consumption of pizza and beer does take a lot of interior room however.
We have no idea what’s in the gray box or why it’s there. Is it connected to anything except the hull?
Happy trails to you.
Captain Mark and crew.

[tkeithlu]

Mark, are you implying that you still need ballast despite your never ending succession of blubberbutt manatees? One crew on board and both your rails are underwater.

I'd like to see one of them do a circumnavigation with his/her tongue. I do it every time there's a lunch-sized fly behind my head.

[Rhod72]

I removed the lead over the weekend, I'd estimate it to be 80kg. I'll be fitting two 30kg batteries in it's stead

[Uncle Bob]

Originally Posted by Rhod72

I removed the lead over the weekend, I'd estimate it to be 80kg. I'll be fitting two 30kg batteries in it's stead

Before you add the batteries, stand back and look at the boat, does it now "lean" slightly to one side? If so then the weight was probably calculated to correct that and the replacement weight should be the same.

[Breaking Waves]

Originally Posted by Manateeman

A lot of commercial vessels have a battery dedicated to radio and sometimes AIS and a medical phone. I’m not sure it’s a Coast Guard requirement

The European commercial certificates (like MCA and RINA) require a separate battery for the "for the purpose of conducting distress and safety radiocommunications" - separate from the engine and 'house banks. It can be a reasonably small battery and is often used as a 'filter' to provide nice clean power to the nav station. I don't know the US CG commercial requirements, never taken a vessel thru the US process, but it probably has similar requirements.