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Postby Davinci » Wed Jul 08, 2009 6:34 pm

PaulC wrote:, try foam high in the boat


Yes, that's what I did, by adding some inside ballast-chamber.
As I said, there's no other place left, even in the cover which fits very tightly over WTC assemblies.
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Postby Sub culture » Thu Jul 09, 2009 5:03 am

What sort of battery is it. Is it a lead acid block?

A cylinder of batteries running under the wtc in the keel would make things much more stable
'Why are you staring at an empty pond?'

Want to dive your boat in crystal clear water? Then you had better Dive-in- http://www.diveintomodelsubmarines.co.uk
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Postby Davinci » Thu Jul 09, 2009 10:56 am

Sub culture wrote:What sort of battery is it. Is it a lead acid block?

A cylinder of batteries running under the wtc in the keel would make things much more stable


It's a thin flat SLA that lays on bottom of hull, on top of lead weight. Only about 1" thick.
Changing to this type battery helped greatly but still not enough.
See pics:

Space under WTCs is taken by lead bars.
This is a fairly flat bottom hull (not much of a V shape), except for the 1" wide keel which is full of lead weight.

Image

Image
Last edited by Davinci on Thu Jul 09, 2009 11:44 am, edited 1 time in total.
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Postby Davinci » Thu Jul 09, 2009 11:30 am

Here's a pic showing shape of keel, taken during construction before weights were added.

Click pic to enlarge:
Image
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Postby Sub culture » Thu Jul 09, 2009 12:36 pm

Okay. I'd advise you find another home for the lead acid pack.

Remove the lead weights from the keel, make up a 12 volt (10 cells) pack of either sub c or AA NimH batteries. Wrap them in heatshrink and cap off the ends with silicone sealant to make the assembly waterproof. This will lie in the keel. Now get some sheet lead and place that in the hull under the cylinder.

I reckon that should sort it,the NimH's will also give you more capacity. If it doesn't you are really looking at a separate keel or removing top weight somehow.
'Why are you staring at an empty pond?'

Want to dive your boat in crystal clear water? Then you had better Dive-in- http://www.diveintomodelsubmarines.co.uk
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Postby Thor » Thu Jul 09, 2009 2:44 pm

Is there foam underneath the deck on the top half of the sub? I didn't see any pics of that.
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Postby Davinci » Thu Jul 09, 2009 2:50 pm

I'd advise you find another home for the lead acid pack.



:D LOL :D
I might as well get another hull and Start over again to do that. :shock:
No Thanks!
Like I said it looks like the latest foam addition is going to make it usable.
I need to do more testing in deeper water to determine how much of a Real submarine I'll have tho. I've been testing in hot-tub.
Hey, a surface cruiser is okay too. :wink:
It's been a learning experience. The main thing I learned was how easy it is to make this hull design be Top-heavy. :cry: Since it was when I got it.
Last edited by Davinci on Thu Jul 09, 2009 3:08 pm, edited 3 times in total.
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Postby Davinci » Thu Jul 09, 2009 2:55 pm

Thor wrote:Is there foam underneath the deck on the top half of the sub? I didn't see any pics of that.


Yes, a little in the front of cover. Just not much space under there.
Plus it needs good ventilation for air and water, thru holes in cover.

Foam in cover only effects submerged balance tho, not surfaced balance, which is where it's main problem is.
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Postby raalst » Thu Jul 09, 2009 4:15 pm

if I understand you correctly your boat rolls side-to-side and to battle that
you added lead and foam and now when submerging it stands on it's nose.
right ?
if so, you can try adding weight low in the tail instead of foam high in the nose to get the boat level. this will not aggravate the roll, just the waterline.
Regards,

Ronald van Aalst

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Postby Thor » Thu Jul 09, 2009 5:03 pm

Always start with your submerged trim first. Stick thin strips of foam to the sides of the top . This will allow the air to vent. That deck is very narrow, it will not need much space for the air to vent. When and only when you have the submerged trim fixed do you start to mess with surface trim. If you are losing control of the boat in a dive, you must fix this first. You must have control of the boat first, before you start tweaking it. As Paul Crozier said, foam floatation as high as possible, weight as low as possible. From what I have seen in your pics, you have set yourself up for a rollover by having the foam down so low. You may have to settle for a slightly non-scale surfaced trim in order to achieve a properly operating sub(the boat may set a bit low). Get that foam out from under the lowest reaches of the boat and get them up higher in the deck.

I am not trying to beat you up here. I can pick you your aggravation. Just trying to help you out!

Matt
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Postby Davinci » Fri Jul 10, 2009 1:07 pm

raalst wrote:if I understand you correctly your boat rolls side-to-side and to battle that
you added lead and foam and now when submerging it stands on it's nose.
right ?

No, I should have explained that it was sinking Level, not bow first.
It was going down way too fast and way too easy, not a controled desent.
Last edited by Davinci on Fri Jul 10, 2009 1:23 pm, edited 2 times in total.
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Postby Davinci » Fri Jul 10, 2009 1:13 pm

Thanks for the suggestions, Matt.
Hopefully the foam in ballast-chamber fixed the problem.
I now need to get it to the lake to test it's dynamic dive capability.
Since it don't look like the static dive capability will ever be what I wanted. Just too top-heavy for that.

Davinci wrote:I need to do more testing in deeper water to determine how much of a Real submarine I'll have tho. I've been testing in hot-tub.
Hey, a surface cruiser is okay too. :wink:
It's been a learning experience. The main thing I learned was how easy it is to make this hull design be Top-heavy. :cry: Since it was when I got it.
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Postby Davinci » Wed Jul 15, 2009 2:56 pm

I'm getting very close on the flotation trim.
The stern sets a little low when surfaced all the way but there's No roll now, which is a big improvement.
But taking any weight out of the stern makes it start to roll, so it may have to stay the way it is.
I only have dynamic dive, below periscope depth, which is great.
I really don't need it to static dive.
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Postby Davinci » Thu Jul 30, 2009 3:33 pm

With a great deal of work I've got it at a proper level when surfaced.
The problem was that when they made the hull cover piece, instead of installed small buldheads to make it ridged, they used about 4 times too much resin making it 4 times heavier than it should be.
I used a dremel drum-sanding bit to grind out a great deal of the resin.
Man, what a mess with resin dust. :roll:
But I got topside lightened enough so I could remove some the lead from keel without it rolling.
It was a Major modifcation but worth it to get it riding 'High and Proud'. :D

I'll know next time to check that before buying a fiberglass hull. :wink:
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Postby Mike Dory » Sat Aug 01, 2009 10:55 am

Howdy, Please allow me a second here, to THANK all those who sent me e-mails and cards while I was in the Hospital. It ment alot. It is so good to be home again... Barb and I thank all of you...

Now about this boat, Dont forget, you can add more of "the pink stuff" inside of the conning tower This won't do anything for your surface trim but it will help you to "catch" your boat as you dive and keep it off the bottom. This will improve your control of the boat as you dive. Next. Go to the regatta, with your boat, There will be lot's of guys there to give you a hand in triming your boat. not to mention it's just great fun... Best Wishes to all.......Mike Dory
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