Model Boat Mayhem
Mess Deck: General Section => Beginners start here...! => Topic started by: Billyruffian on January 07, 2008, 08:38:45 am
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Another part of the learning curve that has come back to bite me is that I have been working on the Caldercraft Talacre.
I thought I was doing the right thing by getting the ballast in and all below deck stuff first. I got the water line sorted and started loosely putting in the lead along with the motor, gell cell battery etc. Got it sitting well about 1/2" below the water line.
The problem was that the lead strips got themselves mixed - don't ask long story - and the stuff that went in and bedded onto P38 now takes the bow end to just over the waterline.
How can I correct this?
The battery is a Gensis gell cell 6v 4.0AH. Would changing the gell cell for a battery pack save much on weight and would it still give decent "on the water time"?
Or maybe someone knows how I can break a P38 bond?
Any help or advice would be much appreciated.
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BillyR
Can you put the 6v gel cell onto a scale and post the weight on this thread? It's probably quite a bit heavier than the equivalent NiMH pack, so don't lose heart.
FLJ
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You can break the P38 bond, but it is fraught with danger!!
I just break up one end with a flat screwdriver and slowly twist, to lift a little of the lead at a time.
Patience is the main factor here.
If in doubt place some plywood under the screwdriver blade to spread the load, but always checking the hull doesn't flex enough to crack the paint.
It does work, but take your time and be careful and you can get the lead out.
Bob
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Thanks FLJ,
The weight is 850g.
Thanks again
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I thought that breaking the bond wouldn't be easy so I am hoping going the different battery route would save me.
Thanks
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P38 doesn't have great mechanical strength and is flexable so isn't too bad to break.
Bob
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Depending on how bad the problem is, adding a bit of weight at the stern may be enough to bring the bow up sufficiently without making the stern too deep. A bit of extra draught on a model like Talacre does no harm as it gives the prop more bite and if the model is slightly below its propper waterline in the bath it won't be noticeable on the pond.
As FLJ says, an equivalent NiMH pack will almost certainly weigh less than the gel cell and give you a bit more capacity and power as well. Weight is only about 420 grams too. See: http://www.modelpower.co.uk/acatalog/Power_Packs.html
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You may also be able to cut the P-38 out with something like a Dremmel fitted with a cutting head but be warned it will make a mess and you will need to wear a mask. Also take care that you don't touch the hull and weaken that.
As Bob says you may be lucky in being able to prise it away but it will come out one way or another.
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Component Shop list a 5-cell (6v) 4300 mAH Sub-C NiMH pack at £16.75. If you pro-rata Colin's value for a 6 cell pack then this one is about 350g, which in old money is over a pound lighter than the gel cell. I'd suggest you try out the lighter weight in your model first - some sugar in a polybag would be a cheap and cheerful substitute for the battery pack. (Now watch - some herbert is BOUND to ask what currant you use to charge sugar.....).
You'd need a different type of charger for NiMH packs than the one you use for the gel cell, but the same supplier lists those too. As they say, "I have no connection with www.component-shop.co.uk, I'm just a satisfied customer".
If I were you I'd only contemplate digging out the P38 as a last, desperate measure.
Good luck!
FLJ
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Hi Billyruffian,
I had a similar problem when I used lead blocks in a sub. I solved the problem by drilling half inch holes into the lead. Then for final trimming, I just trickled lead shot into the holes, then a drop of epoxy to hold them in place.
Bob
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Thanks all - as usual the help on here is fantastic.
I think I will try the Nimh battery first - nothing will be wasted as the bug has bitten ;)
I will also try a little more in the stern - thanks Colin.
If this doesn't solve the problem then I will have a go at digging the P38 out.
Thanks again
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Billyruffian,
I do like refurbishing models so have removed ballast from lots of models, not ruined a hull yet!!
It isn't as hard as it sounds with a little patience, then you can ballast her exactly as YOU want.
The base P38 helps to support the hull.
Bob
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Billyruffian
From what you say you have a half inch to play with and as the superstructures and other bits are relatively light on this model I think that putting her in the bath, fully loaded and then simply press her down at the stern and see where she sits when level. I reckon you will be close to bang on, unless the weight in the bow is really excessive. If this works it will save you time and money on new batteries.
Barry
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Hi Barry,
Right now, in the bath, she sits just below the waterline at the bow and about 1/2" above the waterline at the stern - little bit of rudder visible.
How's progress on the Lady T?
Your tip for weathering works a treat too thanks
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As per my PM just try adding ballast at the stern till she levels up. Should be okay.
Not much happening with Lady T. Still deciding how best to do the inside of the bulwarks....but hope to get some serious work done on her in the next week or so.
Glad the weathering worked...Take care
Barry
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Depending on how bad the problem is, adding a bit of weight at the stern may be enough to bring the bow up sufficiently without making the stern too deep. A bit of extra draught on a model like Talacre does no harm as it gives the prop more bite and if the model is slightly below its propper waterline in the bath it won't be noticeable on the pond.
As FLJ says, an equivalent NiMH pack will almost certainly weigh less than the gel cell and give you a bit more capacity and power as well. Weight is only about 420 grams too. See: http://www.modelpower.co.uk/acatalog/Power_Packs.html
Although I take your point here, in general it is a bad idea to add weight to counteract a problem. Much better to shift weight. The original posting should be a lesson for us all....i.e. add weights a little at a time and don't secure them until absolutely certain they are correct. Personally, I always make sure I can move the weights around and never fix them permanently as even a change of battery can upset the balance. (lots of little "handbags"!).
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What you can do is simple get heat gun and slowly heat up the lead and p38 this will make is soft don't go at it like a bull in a china shop slowly slowly and it will work.The heat will soften the p38 BUT you don't have to get the hull so hot as it will burn the paint
Stavros
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What you can do is simple get heat gun and slowly heat up the lead and p38 this will make is soft don't go at it like a bull in a china shop slowly slowly and it will work.The heat will soften the p38 BUT you don't have to get the hull so hot as it will burn the paint
Stavros
Or use a hair dryer, not so intense. O0
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On my original MB review model of Talacre I used a hairdryer to correct a distortion in the GRP hull so I would be very careful about using heat in the hull, you might end up with a different shape! There are easier suggestions on this thread - use a lighter battery, put a bit of weight in the stern or simply drill out some of the lead. (or all of these!)
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You appear to only be a little over weight,the boat that is!,so why not drill some holes in the ballast to lessen the load?.
Good luck.
Len. ::)