Electric magnetic field heath problems and sea sickness

[MultiCountryDon]

Originally Posted by Ralsy

Apologies given, as this post is based not on a sailing boat but on a powered cruiser, but I think the topic is still relative to both.
Electric magnetic field heath problems and sea sickness
In alot of boats, passengers sit very close to electrical systems (such as batteries) of significant power, usually for a considerable amount of time. Apparently the currents achieved in these systems and the short distances between the power devices and the passengers mean that the latter could be exposed to relevant magnetic fields. In my case approx 1000 amp 12v battery bank underneath the main cabins bed, around 12 inches below the bottom of the mattress. I'm wondering if the hazards of magnetic field exposure or electromagnetic radiation (EMR) must be taken into account?
Is it usual to put such a large storage of batteries under the bed you potentially spend 1/3 of your day on?
The previous owner of this particular boat has told the broker he doesn't want anything more to do with the boat as all his family members get sea sick on the boat and most other people aswell if they come aboard for any extended lenght of time.
The sea sickness could be enhanced by the relatively narrow beam to length of the boat aswell as the heavy steel superstructure which could make it a little rolley at times. It's a 55ft long, 15ft beam, 45 tonne steel displacement pilothouse cruiser. There is a stability report available on the boat which stipulates the necessary requirements for when cruising such as making sure water tank">fresh water tank is full, gray and black are empty, centre fuel tank is empty, the other 4 are balanced except for tank number 1 which needs to have 350 litres of fuel less than tank 4. The boat does have Naiad Stabilizers but still thinking it could potentially be quite rolley.
So there are 2 questions,
1 - could the close proximity of the batteries be a potential health problem OR add to the sea sickness of passengers through the EMF on a steel boat?
2 - could the build of the boat as described be a problem in anything but smooth cruising conditions?
I have been for a sea trial but unfortunately conditions were smooth.

Rod Sterling and Twilite ZZZZone come to mind.

[chris95040]

Originally Posted by Ralsy

4 x Lifeline GPL-8DA 12 Volt 255 AH AGM Deep Cycle*= 1020 AH battery bank?

In your post, you didn't say 1020 AH. You said "1000 amp".

Imagine trying to talk about racecars without a firm grasp of the difference between "Speed" and "Distance". That is very similar to the difference between power and energy, and the difference between amps and amp*hours.

[Ralsy]

Originally Posted by dorymate

Maybe when you see how many posts I've made over the years you may question my reason for replying..well I am a retired Merchant Marine Master and I have had experience during my tenure as Master with a small Passenger Vessel of 120 feet in length with the same problems and this vessel was very unstable during bad weather conditions(very frightening at times to say the least) after a few years of operations the Naval Architects finally solved the problem by increasing her beam by welding sponsors along both sides this proved out to be very satisfactory...whole different ship..

Pardon.my lack of knowledge, but what are sponsors?

[Ralsy]

Originally Posted by chris95040

In your post, you didn't say 1020 AH. You said "1000 amp".

Imagine trying to talk about racecars without a firm grasp of the difference between "Speed" and "Distance". That is very similar to the difference between power and energy, and the difference between amps and amp*hours.

Apologies, I stand corrected.

[chris95040]

Originally Posted by Ralsy

Apologies, I stand corrected.

No worries bud - here's a thing I wrote a while back on the subject:

Originally Posted by chris95040

Energy is the amount of work you need to do to accomplish some task. If you lift one case of beer off the dinghy onto the boat, you've done some work. If you lift a second case of beer, now you've done twice as much work. Whether you lifted them both at the same time or one after the other doesn't matter, it's the same amount of work, aka energy, in total. 2 cases worth.

Power is how much work you can do in a certain amount time. I'm a wimp and can only lift one case of beer at a time. My buddy can lift two. He's twice as powerful as me. If hoisting a load of beer onto the mothership takes 10 seconds, my power output is 1case/10seconds. My buddy's is 2cases/10seconds.

To be fair, my buddy and I will each unload half the beer. In total, when we are done loading up, we'll each have done the same amount of work (aka, expend the same amount of energy) but since my buddy is twice as powerful as me, he'll be finished with his share of the work in half the time.

Additionally, if you want to know how much work I can do in 60 seconds, multiply my power output by 60 seconds. (1 case / 10 seconds)*60 seconds = 6 cases loaded on deck. Power, multiplied by time, equals energy. Mmmmmm beer.

For a given voltage,

the Amp is a measure of power.

and

The Amp hour (Ah, amp * hour) is a measure of energy.


Power, multiplied by time, equals energy.

Example: Your alternator may be really powerful and put out 200 amps. Run it for a few seconds and you haven't stored much energy in your batteries (200 amps *.001 hours = 0.2 amp hours), you won't be able to do much work with that! Run it for an hour and you'll have 200 amp hours of energy, nice, time to chill the beer.

[Ralsy]

Originally Posted by chris95040

No worries bud - here's a thing I wrote a while back on the subject:

Great explanation. I'll definitely go for the beer.

[StuM]

Originally Posted by Ralsy

Pardon.my lack of knowledge, but what are sponsors?

sponsons ? "a projection on the side of a boat, ship, or seaplane."




(pardon my bold!)

[StuM]

Originally Posted by chris95040

No worries bud - here's a thing I wrote a while back on the subject:

Or f you want to be really pedantic, here's a longer one I wrote:


http://www.cruisersforum.com/forums/...ml#post1933764

[sanibel sailor]

No one (generally) gets nauseated in an MRI and thats some badass magnetic field.

[Ralsy]

Originally Posted by StuM

sponsons ? "a projection on the side of a boat, ship, or seaplane."




(pardon my bold!)

Thanks

[Ralsy]

Originally Posted by StuM

Or f you want to be really pedantic, here's a longer one I wrote:


http://www.cruisersforum.com/forums/...ml#post1933764

Great explanation. Thankyou

[NorthernMac]

I wouldn’t worry about the batteries.

[LittleWing77]

Originally Posted by Ralsy

The previous owner of this particular boat has told the broker he doesn't want anything more to do with the boat as all his family members get sea sick on the boat and most other people aswell if they come aboard for any extended lenght of time.

The sea sickness could be enhanced by the relatively narrow beam to length of the boat aswell as the heavy steel superstructure which could make it a little rolley at times. It's a 55ft long, 15ft beam, 45 tonne steel displacement pilothouse cruiser.

There is a stability report available on the boat which stipulates the necessary requirements for when cruising such as making sure fresh water tank is full, gray and black are empty, centre fuel tank is empty, the other 4 are balanced except for tank number 1 which needs to have 350 litres of fuel less than tank 4. The boat does have Naiad Stabilizers but still thinking it could potentially be quite rolley.

I have been for a sea trial but unfortunately conditions were smooth.

So it sounds as if you have not bought her yet...?

Is this a one-off build?

"Necessary requirements" for cruising
(as re-quoted below) are incredibly onerous.

Originally Posted by Ralsy

making sure fresh water tank is full, gray and black are empty, centre fuel tank is empty, the other 4 are balanced except for tank number 1 which needs to have 350 litres of fuel less than tank 4.

Hypothetically, so you've met all of the requirements above and left the dock with you and family and/or friends aboard. Grey and blackwater tanks are empty, but you're underway and not far enough offshore to discharge directly overboard... once the black/gray tanks fill up, how does that affect the boat's stability?

Equally, you are becalmed and begin to motor for an extended period, depleting your fuel tanks. How does *that* affect the stability?

Sorry to say, but this boat you're trialling sounds like an extremely bad build. They've added stabilisers - which haven't helped. I would pay attention to the previous owner and stay away. Or maybe you all have cast-iron stomachs so you don't care...

Apologies if you've already purchased, LittleWing77

[Ralsy]

Originally Posted by LittleWing77

So it sounds as if you have not bought her yet...?

Is this a one-off build?

"Necessary requirements" for cruising
(as re-quoted below) are incredibly onerous.


Hypothetically, so you've met all of the requirements above and left the dock with you and family and/or friends aboard. Grey and blackwater tanks are empty, but you're underway and not far enough offshore to discharge directly overboard... once the black/gray tanks fill up, how does that affect the boat's stability?

Equally, you are becalmed and begin to motor for an extended period, depleting your fuel tanks. How does *that* affect the stability?

Sorry to say, but this boat you're trialling sounds like an extremely bad build. They've added stabilisers - which haven't helped. I would pay attention to the previous owner and stay away. Or maybe you all have cast-iron stomachs so you don't care...

Apologies if you've already purchased, LittleWing77

Not yet and leaning towards not buying. It's extremely frustrating looking and looking only to find out something is not right. If only I had another couple of hundred grand, it would open up a whole new world ofpossibilities.

[BoatBumm]

As a Board-Certified Emergency Physician, PhD Neuroscientist, and a serious sailor, I am unaware of any real science that supports that magnetic fields have any effect of any kind on the human body. We have nothing in us, especially our brains, that is magnetic*. MRI scanners use massively strong magnetic fields to force water molecules to "flip" and emit a weak radio signal, but those too have never been shown to cause any ill effects. The people that run those machines are routinely daily exposed to the fields - no problem. And those magnetic fields are many orders of magnitude stronger than anything a boat's 12 volt system would ever generate. That would require massive currents to generate a strong magnetic field. And if the return electric wire runs parallel to the wire that you are worried about - the two induced magnetic fields would cancel each other out. (Hence the routine recommendation for a "twisted pair of wires" to supply power to the compass light - cancels out any induced magnetic field that could affect the compass.) Running around on the boat with a simple handheld compass while someone is turning circuits off and on would tell you if any magnetic field is being induced outside of Mother Earth's. And even if it is - again it would be very weak and there is zero evidence that would have an effect on a human. Anyone who says that it does are likely in the "magical crystal amulet and copper bracelet" crowd.

Any "excess seasickness" associated with the boat is likely a combination of the boat's design (especially tendency to roll), the sea state, the individual's general susceptibility towards seasickness, and perhaps psychology - if you think the boat is likely to make you seasick - it probably will.

(*There are some recent reports saying that some birds that navigate long distances to migrate have sensors in their brains that can detect the Earth's natural magnetic fields - fascinating! Humans don't have those.)