# Self Leveling Bed

Discussion in 'Boat Design' started by Bahama, Jul 2, 2010.

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### BahamaJunior Member

I was talking to some family members about my thoughts on building a boat and one joked that they didn't see a self leveling bed on my plans. We laughed but it did make me wonder about some people who occasionally deal with sea sickness, are selve leveling beds available to people or is the hamock their only choice in the marketplace?

I ask becuase it occured to me that there are really only 2 basic solutions to this: (1) hanging the boat from a pendulum point above, or (2) balancing upon a pendulum point below; both prone to problems.

The problem with hanging is that a large bed would drastically move about the cabin if hung high, and so that's out; hanging from above at a lower axis point would solve the wild horitzontal movement, but it would require lots of ballast, enough that it would alter the center of gravity on a boat; and balanced from below is great until you decide to get in our out of bed... or worse, the 280 Lb. husband gets up only to roll his 90 Lb. wife onto the floor.

But, then it occured to me that this could be solved by "borrowing" some of the weight used as ballast and use that as your pendulum point. to simplify things I would picture 2 separate ballast weights for an X and Y axis, and the weights are simply balanced upon a rod with bearings located in the middle top portion of the ballast. Then cables and pullies are used to reach the bed and would be located from BELOW on the 4 points of the bed. The cables would pull down on the opposite side of the movement to keep the bed level--the bed would still move up and down, but it would be level.

The ballast movement will move at a different speed to the bed because the bed height and/or width is probably different than the swing of the ballast. But this is easily solved through the use of a lever and/or gear system. In fact, you could have a master ballast movement gear that moves the gears of 2 or more beds or other items if you wish. The weight just needs to be substantial enough to overpower most any weight shift of the person(s) sitting/lying on the edge of the bed. The weight needed is directly related to the leverage or gear ratios used, but the weight for each axis would need to be at least 1000 Lbs. for you to see very little dip movement of the bed as you shift around.

And I suppose for rough seas jerking up and down (since the level part would be basically smoothed out), some form of shock absorbers could be installed to easy the vertical jerk impact.

This idea came to me and I thought that I'd toss it out for public domain ownership for any sea sick people out there who'd like to sleep better on a boat; and also to explore the idea more because I'm curious if something like this has already been done.

I personally like the idea of being rocked to sleep and also to be waken up if there is severe weather that I wasn't counting on; but if someone did install such a system they could come up with other ways to alarm themselves if the weather got bad... e.g. I can think of several easy to make electronics projects that I could make that would sound an alarm if the movement got too rough.

Well, there's one amongst the many wacky ideas that float through my head at blazing speeds! Let me know what you think; and if there are any better ideas to this Dr. Seuss gizmo bed.

Take care.

2. ### mark775Guest

Bahama, nothing wrong with a gimbaled bed, if one desires but the "pinch factor" of a thousand pound weight is murderous (deadly), and to be effective, the weight has to move to the wrong side of the boat (the low side). Hammocks have been used for thousands of years for a reason. I love the fact that you're thinking about stuff but "next idea, please"!

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### BahamaJunior Member

Thanks, especially for the chuckle. Just to carry this out a bit more; I was picturing that the bed would need to be framed in tight with metal that would prevent the pinch and would certainly never allow a full finger in there.

But I do see what you mean about losing some lateral energy from the ballast. It's not sticking out there as much and so now you have just dead weight ballast rather than it truly pulling in the direction that you want. Which brings me to another question, but I'll post that with a different title.

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### tom28571Senior Member

A questions is, will a level berth make a significant difference in preventing sea sickness? Much of the motion would still be there. For me, the vertical accelerations are the main culprit. That is why the best sea berths are in the aft part of the boat and near the roll center. I find something comforting in the lee cloth and the side of the boat restricting my body movements. I thought hammocks were typically strung athwartship.

5. ### apex1Guest

Don´t get too serious on that, please.

The final recipe on seasickness is as valid as the unsinkable ship.
About 50% of the enquiries here have something to do with "extra buoancy" and the (natural) fear of getting drown.

Once you navigated the seas, you do not fear the sea, you respect her for being the prime mover of earth. And you respect her for being non arguable.

Our ability to go to sea stands on two feet:

we know that we cannot win,

and we know that this is no hindrance to try again....

But being not seasick, or unsinkable, is a perfect way to forget about the real world at sea...

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### Perm StressSenior Member

Source of seasickness is inside the head of a human (inner ear, where we sense direction of gravity force and accelerations, and sufficient training of brain to correctly process the data), not outside in the boat, bed or sea. In 20 years I have noticed that gymnasts (those who rotate and jump wild on trapezes, rings, horses... ) are never sea sick.

7. ### mark775Guest

To be sure, I have never been in a hammock. I always select a berth longetudinal and wouldn't have thot of one athwart. Time to watch an old movie, I 'spose, and find out...Captains Courageous tonight, maybe, if I can find where I put it!

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### Jeremy HarrisSenior Member

Personally, I've only ever found seasickness to be a problem when standing or sitting, usually when trying to read or do chart work with no view of the horizon. It doesn't seem to be a real problem, at least for me, when lying down trying to get some sleep.

Your idea reminded me of something I did as a student, though. The legs on the bed in my rented room broke. I decided it might be fun (we're talking hippy era here............) to suspend the bed from the ceiling on wires, so that's what I did. Quite apart from the extreme hassle I got from my landlord when he found out, I can say with certainty that this arrangement made me ill, on dry land even without the customary student intake of intoxicating substances................

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### CDKretired engineer

Interesting ideas.
Due to spine damage I can only sleep on an incline of 5-8 degrees, but I would very much like to sleep on a waterbed. Any suggestions?

10. ### mark775Guest

Freeze it? I know you were joking but... a waterbed - there's the gimbaled bed (with sloshing sounds to sleep)!

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### tom28571Senior Member

And your post reminds me of visits to a friends home where we were assigned to sleep in a daughter's bed that was suspended from the ceiling. It did not make me completely ill but did impress me as one of the dumbest ideas to come out of the hippie era.

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### rasorincSenior Member

Design a gimbal bed as Mark suggested with roof gutters on the sides for throwing up in. You could have pumps pushing sea water full time down the gutter to keep them clean and the sound would help you sleep.

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I think that Apex was being very polite with his comments. As I read them, he hints at the wisdom of avoiding boats if mal de mer may be a problem. To paraphrase; "If you cant stand the heat, then stay out of the kitchen".

Gimbaled "beds" might even increase the likelihood of motion sickness. Reaching for absurdity, I propose that the bunk be fitted with a gyroscope. On second thought, gyro precession might muddle the arrangement.

My own experience with discomfort is linked to roll and pitch cycle time. Lumpy seas, where the boat bounces around like a motocrosser, bother me not at all. It is the long pitch cycles that disturbs my innards. Big, heavy,boats running in long swells, I try to avoid. Reeetchhhhh.

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### BATAANSenior Member

Check out the swinging Captain's bed on the whaler "CHARLES W MORGAN" at Mystic Seaport. One skipper has his wife aboard and had the carpenters make him a leveling bed. I worked there many years ago but remember this as being very unusual on ships.

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### Crag CaySenior Member

One of my ships had the whole of the officer's wardroom gimballed. Made it possible to gather for pre dinner drinks even in a gale. Nothing worse than having to hold on when you've got a pink gin in one hand and some tasty nibbles in the other.

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