Author Topic: Oh God I Need Help! - Images Added  (Read 16987 times)

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freightliner009

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Oh God I Need Help! - Images Added
« on: July 08, 2014, 06:57:40 »
I'm trying to ballast my Zeeland as she is very nearly ready to sail but I'm having problems and not ever doing a boat before I don't really know how to remedy the situation I'm in!

Firstly I just floated her as she was to see what happened, no super structure, just the hull, electronics and 12V battery. She behaved like a ball floating in the water but would quite happily have gone over either side if I had let go of her at any point. I found though that when I took the 12V battery out she was very stable, I could lean her right over either side and she would bob back level, but the bow was far too high out of the water. I thought it must be the placement of the battery but having a fixed deck and only an opened top oblong box to fit all of the electronics in I was stuffed for space.

This afternoon I used a keyhole saw and removed the end of the box to gain access into the bow area. There is not a lot of space but I gained about another 4" or so before hitting another solid rib (not a U shaped hollow rib, it is U shaped obviously but is solid in the centre). In this space I am able to place white metal ingots of various weights inside this cavity which brought the bow down and even with the battery in she became very stable as above.

I though wey-hey here we go job done....WRONG! I rushed downstairs to get the super structure placed it on the new stabilised hull and bugger me everything went back to square one. Again she would quite happily have listed either side of level and sunk, very unstable again.

So what do I do now? The more weight I put in the more the water goes above the waterline too. The waterline was pit where the guy that built it had it so does this mean it may need to be changed? Do I actually need a waterline?

Please help, I'd love to go sail her but I'm now worried that if I don't get the help I need to resolve this that she'll sit in the corner gathering dust.

Just added some images......

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Thanks in advance,

Andy.
« Last Edit: July 08, 2014, 09:28:09 by freightliner009 »
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CORONA

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Re: Oh God I Need Help! - Images Added
« Reply #1 on: July 08, 2014, 10:29:08 »
Hmmm.....Freightliner009.

It looks as though you are not finished with the keyhole saw yet.
Your Zeeland center of gravity is above the center of buoyancy, and somehow you need to get the weight inside the hull lowered and/or reduce the weight above the center of buoyancy, while not increasing the total weight of the model.
By googling ship stability I found this for a good demo of stabile & unstable.
http://upload.wikimedia.org/wikipedia/commons/thumb/a/a0/Ship_stability.svg/512px-Ship_stability.svg.png

Some thoughts for you to ponder with the model in front of you. ( none easy for a finished model )

1) If you were to be able to lower the gell cell you have, you would certainly get on your way to a solution.
All my tug models have the gel cell sitting on the bottom of the hull.

2) Reduce the weight of your battery system by going with a different system that is lighter & get it down lower by cutting out the bottom of that really nice compartment, built purposefully for all the necessary components.  Lithium ( e.g. LiPo ) batteries are the lightest, but then you will still need to add more ballast ( again low in the hull or see 4 below ) . Slightly lower than 12 volt system will probably still work fine. Your run time will be reduced, and you will need a good charging system.

3) Reduce the weight of your top house you have already refurbished...... I know, that really sucks, but all of that weight is well above the center of buoyancy so anything you can do to reduce the weight helps with stability, as you already found out during your previous testing.

4) Add a weighted keel. This will serve to lower the center of gravity. Will ( likely ) need to be done with one or more of the above.  Along the same lines as a sailboat keel it serves to help right the right as it starts to heel over.

In your pictures it looks like your waterline is correct, or not too far off.
Th model looks as though it is built with quite heavy materials ( but that might just be difficulty with scale in the  pictures )
Great pictures to show your problems, by the way.
Hopefully someone else can come up with a solution so you don't have to do too much more surgery.

Laurn.



freightliner009

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Re: Oh God I Need Help! - Images Added
« Reply #2 on: July 08, 2014, 10:53:47 »
Thanks Laurn,

Certainly gives me something to think about, how do I approach a weighted keel?
The boat was all hand made by an old school boat builder with steamed timbers. It's a lovely boat and I just want to sail her.

Ooo, before I forget, the bottom of the compartment box sits on the top of the hull ribs so in answer to your question yes I could probably drop the battery lower into the hull but not by much 1/2" to 3/4" possibly. I could also lay the battery on its side to spread the weight a bit more.

Andy
« Last Edit: July 08, 2014, 11:00:28 by freightliner009 »
Proud  father of a new Hobby Engine 1/35 scale Southampton tug and 1/24 scale hand crafted Zeeland tug

CORONA

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Re: Oh God I Need Help! - Images Added
« Reply #3 on: July 08, 2014, 11:26:21 »
Andy,

Yes, really tough one to pull off on a finished model with tight compartments - if only you knew what was out side that compartment....know a Veterinarian ? - maybe they could x-ray it for you..... ha.

I just read your thread on ballasting and the ideas shared there are the same.
Your 2.5 kg battery is not doing you any favours right now, because it is above the center of buoyancy ( COB ) .
If your were able to lower it - good - if not you need to lighten it up some other way above the COB, & add weight below the COB.  If you look back at the link, the further above the COG gets above the COB the worse the stability is.  Yours sounds like it is off quite "a ways" for a small model.

External Keel ballast - If you were here in BC Canada I would suggest you to look for the fishing weights that are made in a form of a rod & coiled - about 3/8" diameter, or perhaps visit a tire shop because they would usually have discarded balance weights to use as a source of lead to try to pour a weight.
It would need to be attached to the bottom of the hull ( best for stability ) or at least added to the hull inside at its lowest level. Less than ideal at this stage for sure, because you will have to continue to cut into that nicely finished compartment.

Suggest having a look at some model sailboat sites to get the idea of the weighted keels, only if you decide that is the way to go.  Most are removable when out of the water.  You will, of course, still need to shed some weight since you are already at the waterline without adding keel ballast, so that should be your main objective first......keep trying - too nice a boat to let it collect dust for sure.

Laurn.



olscuzbut

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Re: Oh God I Need Help! - Images Added
« Reply #4 on: July 08, 2014, 13:05:43 »
Yup,  laying a tall battery on its side helps a lot.  I do that with almost all of my boats using gel cells.

freightliner009

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Re: Oh God I Need Help! - Images Added
« Reply #5 on: July 08, 2014, 13:11:29 »
Laurn,

I'm going to remove some more of that compartment tomorrow, I'm pretty sure all that is behind it are the hull ribs and the keel underneath.

Although I have refurbed the super structure the only extra weight on it is the lifeboat, I removed that and it made no difference. When I fitted the smoker unit I had to remove quite a bit of excess wood on the inside to accommodate it and can't see how else I can make it lighter other than rebuilding it from balsa wood. I've seen loads of tugs with much higher super structures than mine, how on earth do they get those to balance?

I could use a lighter 6V battery but that will drastically reduce the running time especially with two 680 screws, I'd also have to ditch the somker unit which requires 12V to run.
Proud  father of a new Hobby Engine 1/35 scale Southampton tug and 1/24 scale hand crafted Zeeland tug

olscuzbut

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Re: Oh God I Need Help! - Images Added
« Reply #6 on: July 08, 2014, 13:14:13 »
Well----re-looking at your pictures, it would appear that your battery is almost as high upright as it may be on its side.  There are less Ahr  batteries with a lot "flatter" profile that would take up less top heavy space.

freightliner009

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Re: Oh God I Need Help! - Images Added
« Reply #7 on: July 08, 2014, 13:25:18 »
Olscuzbut, (love the name btw,lol),

Any suggestions on what battery mate? As I said I'm running an Action P94 with two 680 motors, the 12V battery in the pics was the smallest I could find.

Andy
Proud  father of a new Hobby Engine 1/35 scale Southampton tug and 1/24 scale hand crafted Zeeland tug

des

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Re: Oh God I Need Help! - Images Added
« Reply #8 on: July 08, 2014, 13:51:51 »
G'day mate.

Some good photos up there.  Looks like a great model, and I can see why you might be reluctant to get into her with the chainsaw.  Also, some good advice above.  But it looks to me that the overall weight is about right, as the boat is sitting near her waterline - the problem is that the weight is in the wrong place - too high.

Yes, you can use a smaller battery, with all of the sacrifices that will bring - less run-time, and the need to add more ballast weight anyway to bring the boat back down to her lines.  But that will still leave you with an unstable model on the water - or it will roll terribly, and possibly roll right over (and stay upside down).

Yes, you can add a weighted keel - or even three (one keel on the centreline, plus two bilge keels).  This will add weight lower down where you need it, but will also add MORE weight, which you don't really need.

I am afraid mate, that the only viable solution to you is to get that chainsaw out, and make a space lower down in the hull (and further forward if you can get it) and get that battery (and any extra ballast) right down on the bottom of the boat.

If your upper works are really heavy, as suggested in your earlier posts, you may also need to get the grinder out and work on some of that material - reduce unnecessary material (eg internal bulkheads or stiffeners), and reduce thickness where you can.  It will all help.

Good luck with all of this.

Des.

olscuzbut

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Re: Oh God I Need Help! - Images Added
« Reply #9 on: July 08, 2014, 15:22:01 »
Hi Andy,
Went back into your "Ballasting" thread to get a full pic of your boat.  Maybe its the angle of the pic, but it looks like  your battery sits above the water line on the side of your boat.  That's not good.  You didn't mention what Ah your 12V battery is.  My pics (if I can get them to load) are the different size and Ah versions I use.  They all lay on their side.  Only the two on the right are 12V, the rest are 6V.  The two in the rear are 6V.  The large one runs my Amsterdam with the smaller one switched in series when I want to operate my water monitor fire cannon.  The pump for it is a 12V windshield washer pump.  Somewhere I have a battery catalogue web site that gives you all the gelcell info, sizes, Ah rating, etc.  You might try googling gel cells.

CORONA

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Re: Oh God I Need Help! - Images Added
« Reply #10 on: July 08, 2014, 18:04:45 »
Andy,

Keeping my ( our ) fingers crossed that you can fit a battery down lower between the frames somehow.
You could ( option 1439, I know ) also make up the twelve volts with two 6 V gell cells in series if it will help fit them in low.
Smoke unit would be cool but......it will work in another model if you can't make it work here. ???

Cheers,
Laurn.

Jarvo

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Re: Oh God I Need Help! - Images Added
« Reply #11 on: July 09, 2014, 01:34:47 »
Andy

Had a close look at your battery, it looks like it is a 12volt 12ah the one i have weighs 8lb, if you changed to a 12volt 7ah mine weighs 4lb 11oz. this change would allow you to put almost 3lb of lead into the spaces under you battery floor, so lowering your centre of gravity, with the smaller battery it would also lay down and lower the centres even more.

This would cost an additional battery but would allow your smoker to stay, but with reduced sailing time!!!!

Are you near Manchester? have a couple of batteries you could try.

Mark
Etherow Model Boat Club

freightliner009

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Re: Oh God I Need Help! - Images Added
« Reply #12 on: July 09, 2014, 02:10:52 »
Thanks for the advice, I feel terribly deflated at the moment. The battery is a Lucas SLA 5Ah (5000MAh), the dimensions of which look very similar to the front left hand side battery in Olscuzbuts image.

How do other tugs with taller superstructures manage to balance?

Des, yep, I have removed quite a chunk of unnecessary wood from inside the superstructure so that it housed the smoker unit, the only extra weight on it is the lifeboat (fibreglass), taking this off too makes no difference plus it will roll either way not just the lifeboat side.

The annoying thing is I have stabilised the hull in the water, even with the 12V battery, the problem now adding the superstructure.

I will cut away more of the compartment and try and get the battery on its side which will lower it but as #i said before the bottom of the compartment is resting on the tops of the hull ribs. I've spent a fortune on this guys, we gotta get her up and running!
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Model Tug Man

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Re: Oh God I Need Help! - Images Added
« Reply #13 on: July 09, 2014, 03:41:43 »
Quite a discussion here. The stability diagram is spot on. You may wish to do away with the equipment box all together. If necessary you could grind the ribs down a little and sister them to maintain their strength. Bottom line is to lower the internal ballast or add external ballast. The box is nice, however it seems to be the source of your discontent. Good luck with the project.
VGJQ

freightliner009

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Re: Oh God I Need Help! - Images Added
« Reply #14 on: July 09, 2014, 04:11:29 »
Just measured the battery and just by laying it down the height of the battery will be reduced by 350mm but does this actually have any bearing on the superstructure because I can balance the hull it's when the superstructure goes on it all goes '*boobs* up'?

Keep all your excellent thoughts coming in, I really appreciate it, this investment has to work ;o)
Proud  father of a new Hobby Engine 1/35 scale Southampton tug and 1/24 scale hand crafted Zeeland tug