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[warspite]

Update, boat brought out from loft  , weighed the various pieces of brass and found some interesting materials that could be used, like two sheets of aluminium one about half a mm thk 4" x 10" (54g), the other about 1mm thk and the same size (but with some slots @ 94g).
 
The current counterbalance weighs about 150g - not the 190g as first thought, its also the 10" long which is about 250mm +, I thought I had the weights of the various brass tubing, I do, its just in the loft.
 
I have a prototype counterbalance that was constructed from the airfix shutter booter rockets, filled with M8 washers and secured with epoxy, though this pushes the vessel over to one side as it is not stepped to be under the keel, and it rotates easily as it is hard to lock it against the hull bottom, it also is a lot heavier and makes the boat sit below the waterline, so I am not keen to use it.
 
other dimensions are  - hull above waterline to bottom of main mast 50mm approx, main mast 12" from deck approx, I think the hull below the waterline is 44mm, overall its about 20" long 500mm give or take including bowsprite.

[warspite]

Update 2, cut into the hull and in the process of trying to use a web cam to vid the inside, wrecked the web cam - it was too large to fit in either the rear or the hole that was cut, so stripped it down, very thin wires which dont take much to break  .
 
found the two washers inside and with a bit of persuasion got them out, now I have sealed the hole and need to check that the seal is good before trying a new fin and bulb.

[warspite]

Update 3, well tried the hull - now sealed  , happy chappy, tested the weight - wow after removing 100g from 20-30mm below the waterline and fitting a tube at 227g including M8 screw in it, sat at about 140mm below the waterline and then attach a 210g weight in the other end of the tube, she sits too low ie 437g at 140mm, with either end pulling the rear down, so tried 150g just under the heavy end of the tube, forward of the screw and pushed over to the left of centre, it still sits lower in the water than I want, but if i make the replacement as 350g ie 210g fishing weight and a 140g in other fishing weight just forward of the screw and with a thinner lighter fin/sail board, then it might just work, maybe a little deeper as well.
 
To get an equally grouped weight what do you use for melting lead and what is the safest and prefered method for moulding it to a specific diameter. I have a 210g weight, it appears to be moulded with a mesh internal connecting to an eye for the line, for this I was concidering just cutting off the rear, then by melting some other weight which I can see if can get from say - quickfit so that it sits in a cup of a made diameter and voila, all the weight together. encase the lot in epoxy with the connection to the hull ie fin and brass tube connecting rod.
 
As long at the combined weight is 357g and she sits as expected and heel over is easily righted then jobs a good un.

[mrpenguin]

@Warspite:

Sounds like you are heading the right direction.

Rather than melting lead (a dangerous process at the best of times) you may perhaps be able to hammer the sinkers you are using to a suitable shape? I have done this for as couple of ballast weights I needed and it worked out pretty well....

If melting lead, make very sure there is no water about as it is will cause violent explosions as it flashes to steam. Lead melts at quite a low temperature and with a gentle flame can be pretty controllable - but be careful....

[warspite]

OKAY DOKEY, not too keen on melting it - hammering I can do  , just have to generate about 330g at about 165mm to acheive the same righting moment, although a little less may be better.

[warspite]

  , well here is my NEW sail board (fin and bulb), it weighs in the region of about 350g (after a bit of weight reduction to the rear part of the bulb  ), tomorrow I will be trying it in the test tank on the boat and see how it fairs, before the reduction, she sat tail heavy but I am hoping that the loss of 22 or so grammes will have a more positive effect, will see.
 
I did go looking at what others had done, and the method employed was basically a thin brass tube inserted and bent through a brass plate soldered to a brass screw which was cut down to reduce its distance from the hull. Then after fitting the fishing weight into a copper straight fitting epoxy was poured in and left to set, whilst it was setting, pieces of cut lead - thanks to the local fishing tackle shop for that - were pieced in around the tapered weight, then more epoxy added.
 
The outer plastic tube was fitted and glued together, which left a 3-4mm gap along one seam, this meant that the other end of the brass tube suitably bent slid down the seam into the back of the copper fitting, this was then epoxied in, note the brass tube extended past the fixing screw by about 110mm facing the bow (this may cause issues later - like having to permanently fix the sailboard to prevent it spinning to the rear).
 
Then backfilled the whole lot with a roll of lead and filled with epoxy, once set, it was weighed - wow 350g +, that is without the fin. Well the fin was made from about 1mm sheet in two parts - plaswelded together at the 'bow' and slid over the brass tube - like a rudder, the thickness was so that I could profile the front and rear, which in hindsight I should have just made it from very thin material and let it naturally form about the tube infilled with epoxy - more of a knife then.
 
After sealing and checking watertightness, then started to cut away excess to get the weight down as it had gone to just shy of 400g, got it down by angling the rear part of the fin and then having to reseal, about 380's so cut the bulb at a 20° at the rear, down to 370's, tested attached to the boat and was slightly tail heavy, so after another cut off, so it was about 45°, this brought it down to about 350's, but it has not been tested yet - but it has been painted so hopefully it will remain water tight, maybe a couple of more coats of paint.

[mrpenguin]

Looking good!

Will stay tuned for updates...

[warspite]

That was the best side - dont tell stavros I painted the outside of this outside  , in this weather    - fool me, if I lose it they only have to check my fingerprints against    - well actually I dont think they have them. ooooo am safe then, b****r stav is on.

[warspite]

Well did a wet test - in the bath - sorry no photo, to busy trying to get her to sit upright and not to one side, large crack heard while trying to adjust the fin - DOH. tried again and no bubbles seen, so tried a heel test, hard a port and then hard a starboard, she rights herself, but I then noticed she was sitting lower, yep full of water, so after removing it, I may need to find out how to reseal her tomorrow, I know the bowsprit allows the water out - quite quickly actually, that's a good thing. I maybe needing to make a proper stand and permanently fit the fin or reseal around the connection to the hull, and I don't know if the leak was due to a badly sealed gun deck or something else, so need to get the test tank down.

I am trying to upgrade this pc to win7 and so the pc is taking up the space needed for the test tank, hopefully everything is nearing completion.

[mrpenguin]

.... large crack heard while trying to adjust the fin - DOH

That sounds ominous 

[warspite]

The extreme heel is to account for wind conditions, as you know, moving forward and staying upright don't always usually occur with yachts let alone square riggers, the test tank will see if she is leaking while vertical, if after an hour she is still dry, the heel to the right for an hour as I know this was the best sealed side, then to the left as this is the suspect side, though I now consider the bow may have an issue just under the bowsprit.

[warspite]

Not going well  , definite leak on vertical, the crack sound may have been the inside fixing for the fin.

so I need to consider what is the best course of action, tried some superglue around the entrance and it worked its way up the thread while it was on its side drying, so the thread needs to be cleaned out, but the way this is going this action might just break the complete connection and the whole stud will break free, so again a bit of thinking needed, its a slow leak but enough, it would have sufficient time to run for about an hour if vertical, but I need to find the other leaks to allow for the extreme heel, so need to fix this leak before moving on to the next.

An option I was thinking of was to definitely break the connection and try to reseal the stud etc back to the inside while it is loose, but that means that the cleaning out of the thread would be problematic.

I do need to fix the fin though, by fitting additional stiffening to the bolt, the fear is that the single brass plate connector between the bolt and the brass internal tube will break, so need to fix this as well to prevent a sinking.

[warspite]

Well I think have sealed it, she's been in the test tank all afternoon, I find it difficult to tell if she is leaking, so took her out and she did not appear to have any water inside, but bubbles are appearing around the area of the connection, though I am unsure as to if this down to a leak or the bubbles from the bottom of the test tank, I am trying to use the steps that are on either side of the vessel to gauge if she is taking water on, but as she moves about it is sometimes difficult to remember where the water level was 

[warspite]

found the leak, its the sailboard again, even after doing a major sealing exercise, a couple of pin holes and where the screw passes through the stiffening plate, though it seems like fill one hole and another appears.

[Brian60]

Who said hot lead was dangerous? Not according to mythbusters

http://www.youtube.com/watch?v=UZio0f7fP04

[warspite]

I'm to chicken to do THAT  ,I suppose its not much different from the fire walkers, same principle, minute time in contact with the hot surface means the skin can take it.

I'm more concerned with the fumes from all the epoxy and glues I am using to fix and build the last 3 vessels - not to mention the flux fumes that escape. 

[mrpenguin]

found the leak, its the sailboard again, even after doing a major sealing exercise, a couple of pin holes and where the screw passes through the stiffening plate, though it seems like fill one hole and another appears.

Some silicon sealant perhaps? I have use something called "wet area silicone" intended for bathrooms etc and it is great

[warspite]

Plastic cement was the reason  , I thought - "i'll fill the top up with some plastic cement and when it goes off it will stop up all the inside holes" - yea right, all it did was weaken the plasticard and when gripping the top it split the card and a hole appeared - DOH !!!!!!

So I need to try again before committing it to water again.

[tobyker]

Can you not pour in some epoxy coating?(Z-poxy?) This should be inert so far as the plastic is concerned, and fluid enough to flow into the pinholes and cracks. Just put some masking tape on the outside of the hull to stop it dripping right through.

[mrpenguin]

.... Just put some masking tape on the outside of the hull to stop it dripping right through.

Now THAT is a clever trick

[warspite]

Will have a go, though for what it is worth the holes, not that big and I did think of putting a hole in the main body and filling all the top section with some epoxy, then repair the hole created. 

[warspite]

Well, after a 12 hour soak in the test tank she sat quite happily as well, butter fingers here dropped the sailboard  , resulting in a major crack so had a think and tried to 'modify' the sailboard to remove the air pocket, ended up having to rebuild the whole thing, so waiting on the epoxy to cure, before a light clean up and doing the painting tomorrow. 

[warspite]

Replacement painted and sat in test tank again, will post a photo soon. 

[warspite]

Here is the photo, quality isnt that good but it does show the change to the rear of the fin

[JayDee]

Hello,
It appears that the Fin is only connected to the hull at the rear end.
If, this is the case, the slightest collision with weeds, the lake bank, or the bottom of the lake, will cause a massive leak into the boat.
Every Fin I have ever seen has been connected and faired into the hull along its whole length.
If the Fin was hit while sailing the Fin could be turned relative to the boat Hull and act as a Rudder !.
I really think you need to alter things before sailing.
John 
www.john-dowd.co.uk