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Perceived instability after adding battery bank

Discussion in 'Technical Discussion' started by cgoodwin, Nov 26, 2014.

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  1. Capt J

    Capt J Senior Member

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    I still think that if you email the current day Feadship with the plans and drawings as well as what you've written here, they would be very interested in helping you. It is worth a try and costs nothing to email them.
  2. cgoodwin

    cgoodwin Member

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    No water in the bilges at all, dry as a bone. I replaced 64 sf of steel below the waterline and know every inch of the bilges, all are accessible.

    The midships tank had a leak and I repaired it, currently I am running new lines and feed and return lines to this tank so I am loathe to fill it with diesel, filling it with water would allow me to pump it over after the test.

    The increase in waterline took place over several months as I removed the entire deck fore to aft and replaced all the steel equally port and stbd, frankly I have no idea if the waterline painted on the vessel when I got her reflected the original waterline or not.

    Spare oil - yes I have 4 gallons stored an a holder on the centerline aft, while they may be Detroits I rebuilt both completely and installed trays with diapers under both motors, to date I have no leaks other than the occasional drip from the crankcase vents.

    She is equally tippy side to side and has no list. the batteries make up only 2.8% of overall weight of the vessel so I still find it surprising that they SEEM to have had a noticeable effect. In total I only added a few hundred lbs of batteries, nothing compared to the weight I removed from the decks of the vessel in the form of water logged rust scale. I suppose the course of action is to remove all the batteries and see if this is in fact the cause of my issue.

    She does not seem unstable at all but before this issue she seemed exceptionally stable. Another factor is that she has only been in her present moorage for several months and is now far more exposed than she was in her previous moorage. Honestly i was hoping for a simpler method of calculating the center of boyancy and center of gravity, it however seems extremely complicated and would require weighing nearly everything onboard and a full 3d computer model.
  3. Capt J

    Capt J Senior Member

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    Do something else. Take as much weight out of the E.R. as possible (spare oil, etc etc....) and move it to the lowest bilge or area in the bow......See what that does to her.......I think the problem is weight fore and aft......and it looks like that was a problem before as they moved the generator and other stuff foward....... I would also get a level that records the swing in degrees and try it before and after so you have a real measure
  4. cgoodwin

    cgoodwin Member

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    SeaEric, Here you go.

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  5. cgoodwin

    cgoodwin Member

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    Capt.J,
    Will do. The midships tank is quite forward of center and would add another 3600 lbs, more than double what the batteries added. The batteries are in Green and the midships tank in red.

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  6. dennismc

    dennismc Senior Member

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    When I read some of the posts on here and realize who got "canned" I wonder who is driving the 'plane .
    just my 2c
  7. Opcn

    Opcn Senior Member

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    As I understand it any weight you add above the center of buoyancy is going to add to initial instability. Anything you add under the current vessel center of gravity is going to lower the VCG. As you heel more the metacenter is going to move past the VCG and you will get more righting arm and have more ultimate stability. Before you cross that line you will have less initial stability. If you can get that mass lower you will cross that line sooner and experience both more initial stability and ultimate stability. If you can't but you can get used to the more tender feel your boat is probably safer in absolute terms now than it was before. If you can move the mass out from the centerline you will probably have a smother go of things but it will not have a profound effect on either initial or ultimate stability. As someone pointed out on the other thread before it deteriorated, moving the batteries outboard means that they will experience greater forces (which is sort of how they provide more moment of inertia) and will mean that it takes a more substantial structure to support them.
  8. Kafue

    Kafue Senior Member

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    LOL, that is funny dennis, the Pilot is still at the pointy end, we are expecting very little turbulence and, speaking for myself, I surely hope that our friend returns next month.
    The "place" is so more interesting with his company, plus he tends to keep the crew more honest, if only he could control his spray to a fine stream and not a throw of the bucket, handle and all!
  9. Opcn

    Opcn Senior Member

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    If we keep revisiting past slips the docking fees are going to start revisiting us. Best to keep your eyes on the forward horizon.
  10. NEO56

    NEO56 Member

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    First of all, I can't fathom a 56' vessel with a 13' beam, especially a steel hull. I'm sure I'm going to get blasted for this...but from my idiotic perspective, I used to own a 16'8" Old Town canoe, flat bottom with round chines. I used to pack her down with conservatively 300 pounds of gear including a 50 lb. battery for my trolling motor, not including myself along with my wife. And she'd still only have 4 inches of draft. My point being that 15 pounds that was not compensated to the other side of the Center Line caused instability to the point that I could not stand in the back and cast for Bass along the shore line of the River. Without all of the technical mumbo jumbo, take half of the Batteries and move them across the Center Line exactly where the other half is off of Center Line. If that doesn't fix your problem, then pull out your wallet and pay the "experts" to fix it. And yes, she's a very pretty boat. So to quote my dead Engineer Dad...start with the most simplistic solution, and work your way back. Has it ever occurred to you that maybe you've been living the good life too long, and have gotten fat, which is causing the list???
  11. Capt J

    Capt J Senior Member

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    I would get a recording level and see how many degrees it measures in it's present state. Then, After looking at your initial post, the easiest thing to do, might be just to empty the fresh water tanks as they are right in the stern and emptying them only requires opening a faucet, that will remove almost 2800 lbs from the stern and shift the trim of the vessel foward quite a bit. Measure that. Then you could fill that midship fuel tank with water and see if adding more weight than you took away (by emptying the water tanks) makes the boat less tender, measure that. Then re-fill the water tanks in the stern and measure it again. It might be more of where you have the weight located, and not how much weight you have added.

    I worked on a canoe stern 97' steel motoryacht similar to a classic Feadship and your boat. She drew 8-9' of water depending on load. We had 2 day tanks of only 100 gallons each, then a 1500 gallon bow, 1500 gallon stern and port and stbd 1500 gallon saddle fuel tanks, she also had a 1000 gallon freshwater tank in the bow. I always swore sometimes when that water tank got very low that she was a little more tippy getting on and off or walking from one side deck to another......but on such a large boat it's really hard to tell the difference.
  12. Kafue

    Kafue Senior Member

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    Well said.
  13. Kafue

    Kafue Senior Member

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    The OP started a new Thread on his problem because he wanted to stop the topic from drifting into insults. Your comment, had it been made by another member/s, would be taken very badly.
    It certainly hasn't added anything of value to the thread.
  14. NEO56

    NEO56 Member

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    Sorry Kafue, I was just trying to add a little levity to this thread...it wasn't my intention to insult anyone. You should know by now how much of a smarta*s I am. I'm of the opinion that a 56' boat with a 13' beam, kind of relates to the Northern Marine incident. The boat wasn't properly weighted, and therefore capsized. The OP indicated that there's zero fuel in the tanks, which tells me the boat wasn't designed as a dock queen, and the builders assumed there would be some type of fuel aboard to stabilize the vessel. Kinda of like tossing a 60 ft. mast on a boat that doesn't have a keel. I'm just trying to be practical about this whole thread. I'm thinking that with proper liquid quantities aboard, battery placement wouldn't be an issue. I'll just shut up and not contribute to this thread anymore. I hope everyone had a nice Thanksgiving.
  15. cgoodwin

    cgoodwin Member

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    Wow, I have to say, some of you seem to be on a mission to be armchair trolls. Look, a guy is posting here on a yacht technical forum with a yacht technical problem looking for some advice on how he might solve the issue, isn’t what this technical forum is for? Put on your big boy pants and be helpful or shut it, its an intellectual exercise, if you don’t have the intellect to do anything other than be a smart ass, then keep to yourself.


    Opcn – The added weight is only 8” above the bottom of the boat in the lowest place, I could not move it any lower without mounting them outside the hull. Any attempt to move them out to the sides would require raising them as the hull is rounded. Remember this vessel is not wide at all, 13’ overall, there is a 4” gap on each side between the hull and the water tanks, and the water tanks are about 1.5’ wide, so there is only about 8 of space left to right.


    NEO56 – “Has it ever occurred to you that maybe you've been living the good life too long, and have gotten fat, which is causing the list???” She does not have a list and I am a working guy. On my own since I was 15, I have a metal shop I built and a business maintaining and restoring German cars. I cut out and replaced the decks myself, ever inch of weld and every dustpan of rust scale. I refinished every board, bent and repaired them and expoied them back down with my own two hands. Every heat-gun burnt , scraper gouged and tip sanded raw finger was mine, I dusted painted and varnished every last inch. I restored the 64 year old metal refrigerator, gutted all the wiring and wired every circuit myself. I scrounged, traded for looked for deals on or built every system. I cut out weak points in the hull laying on my back in the rain with welding slag running up my sleeves and welded every stitch. I built the cradles to lift the rusting old Jimmy’s out of the stringers and I rebuilt them evenings and weekends while being a single parent. So no, I don’t think I have been living the good life too long and gotten fat which is causing the list, read the post, its about perceived instability.


    Capt.J – Water tanks are outboard of the engine room and centered, aft fuel tanks are aft. I have removed far more weight than I have added and the weight I have added is lower than the weight I removed. As for the boat you used to work on, I am sure you were correct, I have buddies who are fishermen who can tell if there is water in the bilge or if tanks are getting low by feel. My vessel is not bouncing all over or rolling uncontrollably, but she is definitely tippier and hence my questions. It seems that I have not added much weight but it is concentrated in the middle and at the lowest point. I’ll take the battery bank apart this weekend and drag the cells outboard a bit and see. Realistically there is only room for about 10” of movement stbd.


    NEO56 – Read your last post. No harm no foul. I was thinking the same thing! Here is the deal with the boat. Legend has it that Witsen and Vis made 4 of these hulls as military patrol boats, two were delivered as such leaving them with two hulls. Brigand was made from one of those hulls as a deep sea sport fish and lived off Montauk in the summer and Bimini in the winter. The other was built as a bridge deck version with steading sails and named the Capri. No information on the Capri is available.


    If you search my user name you will see that the only posts by the owner of Feadship on this forum were in response to one of my posts from 2008 when I first bought Brigand, and there was some doubt that she was even a Feadship because there were no known records. Later he put me in touch with the Feadship family archivist who was very helpful and located some of the original brochures. She was definitely not designed as a dock queen and I am sure was intended to have full tanks. I bought her with no fuel in the midships tank at all because the PO had hidden the fact that the top of the tank was rotten.


    I brought her 60 miles to where she currently lays with that tank empty and she was not as tippy as she is now. In addition she had batteries in the same location where they now are although they were slightly more stbd, about a foot. I have removed maybe a thousand lbs of rust and old systems from the boat, rust on the decks and old systems in the engine room. I am posting because I don’t have the funds to hire a naval architect and am surprised that the addition of these batteries would make a noticeable difference and am looking for some theories as to how, without hiring a naval architect, I might solve the issue. As soon as the ice thaws, I’ll fill the midships tank.
  16. NEO56

    NEO56 Member

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    Hi cgoodwin, I appreciate all the work you've put into her, and it shows, it's a job very well done, and I'm sure you have still, a very long "to do" list. I am not trying to be a smarta*s here, but have you put on a mask and gone under the boat? Is it possible a very huge log or telephone pole has drifted underneath and wedged itself under the hull? I don't know where she's berthed so I don't know if that's possible. As opposed to spending a lot of money for a NA to take a look, I'd rule out the obvious first. It could be something just that easy. I know I'm a moron when it comes to the inner workings of a boat, which is why I'm here. I can drive and handle with the best of them, I always had someone or hired somebody to "work" on the boat. I would think that what every one here is doing there best to help...and based on the fact that after the installation of the batteries is when you noticed this phenomenon, I'm assuming this perception did not take place gradually, it was an over night thing...correct? So something you did recently needs to be undone, or re-balanced. And yes, I will shut up for the rest of this thread.
  17. AMG

    AMG YF Moderator

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    As I have suggested a couple of times now, this combined is most likely what have made the boat "tippier", as in getting a faster swing sideways.
  18. olderboater

    olderboater Senior Member

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    Cgoodwin

    You clearly state a very possible and perhaps likely cause of your problem.

    "I have removed far more weight than I have added and the weight I have added is lower than the weight I removed."

    For fear of being added to your troll list, you're responding but not hearing.

    Quote from very early in the other thread:

    "If the added weight is located below the initial vertical center of gravity, VCG will be lowered, GM will increase and produce a faster roll rate."

    Note we're not saying less stability, just faster roll rate. We don't know that stability has been impacted at all.

    It's as if you're still trying to say that nothing you've done should have caused this change. Well, clearly something did. You're saying it doesn't seem like this would have caused it. Well, it did and to those expert in stability, balance, and roll it likely does seem it would have.

    Now at this point you really have two choices. Engage someone expert on the subject to direct you or trial and error.

    If you choose trial and error the first thing would be to return it to it's state before the batteries and see what you have. If it's fine then that will make it simple as you can then experiment by just temporarily placing the batteries in various locations. They are the easiest item you have at the moment to relocate. Now as you continue the project, add and subtract more weight, fill tanks with liquids, it may well change again. A reason it might be wise to only temporarily locate the batteries rather than permanently fastening.

    I'd also say that even with the expert, while you might get it solved quicker, there could still be some trial and error, just more educated trial and error. They don't have a model or the original architecture to work from. What they would have is just a lot of experience in stability and roll including those on major refits such as yours.

    Stability, balance, roll, seaworthiness, performance in various conditions are the difficult part of a major refit. The other things, while taking a tremendous amount of work, are far more basic and easy to understand. Talk to someone like those at Rybovich and ask them the amount of work that goes into that aspect. Lengthening is easy, but lengthening and not adversely impacting is complex. Adding new engines or generators, increasing fuel or water capacity, putting in various other equipment, easy install, complicated to do without adverse impact.
  19. Capt J

    Capt J Senior Member

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    I will say this again. I don't think it's where the weight is in the engine room. I think the problem is your balance fore and aft from what you've told me about the waterline. Instead of doing all of the work of moving all of those batteries around. Put some weight as foward and low as you can in the boat. Even if you have to buy a few 55 gallon plastic drums and fill them up in the foward stateroom with a garden hose. That is next to free and not a lot of work, provided you have an electric pump to pump the water over when you're done with your test. I feel it's weight fore and aft and your weight is too far aft.
  20. cgoodwin

    cgoodwin Member

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