Scaleships Akula II

[He Who Shall Not Be Named]

That's bang on Mr. Merriman, thank you!
I've got just the bit of chipboard for the job in the garage, and a nice glass sheet to move it all around on.

Rogue Sub,
Flexible ruler, that's a good idea as well.

Thanks guys!
CT.

I carefully counted and find that I have over a zillion construction photos in my hard-drive. You guys are in big trouble now that Mr. Caswell (he of the Censor Button) has shown me how to post them to these threads.

David,

[toppack]

I carefully counted and find that I have over a zillion construction photos in my hard-drive. You guys are in big trouble now that Mr. Caswell (he of the Censor Button) has shown me how to post them to these threads.

David,

That's Great!
Pour 'em On!

[Nuke Power]

Oh great Meriman with technological means is like Iraq with scud missiles.

CT Progress report stat.

[He Who Shall Not Be Named]

Oh great Meriman with technological means is like Iraq with scud missiles.

CT Progress report stat.

That Merriman with two-R's, I wear PINK underwear!I wear PINK underwear!I wear PINK underwear!-hole!

[toppack]

:D LOL :D
Mike, This is the Greatest thing since Pink Panties were Invented! I'll drink to THAT!

[Nuke Power]

Fine Mr Pink Panty Hole from now on ill just call you Big David III

[ConcreteTurtle]

Hi again everyone,

Time for a quick update on progress to date.

Sadly I was sick at the end of last week. This coupled with doing some painting about the house unfortunately put paid to getting much done on the mighty Vepr.



I did however manage to make up a "Mk. 1" surface gauge.

It looks a bit rough and ready but works admirably, sliding on a nice pane of glass I've set aside for this purpose.
My thanks again to Mr. Merriman (with 2 Rs) for the template to work from. I'm also going to make up that dremel gauge later as I'm sure it will come in handy.



Otherwise I'm continuing with opening up the limber holes in the top half of the hull, and now armed with my surface gauge the unmarked holes are fair game as well!
I was considering rebating the unmarked location grilles into the hull so they match the limber doors.
Am I going too far with worrying about this? If not, what does everyone recommend for recessing the photo-etch parts into the fibreglass?

I also took John up on his kind offer and dropped over to visit and get some advice this past weekend. He's surely got some nice projects on the go in his workshop, and lots of local knowledge as well. John also reminded me to give the model a good wash with some soap and water (d'oh) this cleared up a lot of the excess mold release and surface roughness.

This week is shaping up a bit better to get some more done, so hopefully I'll have something a bit more impressive to show you all next time.

Thanks guys,

CT.

[Slats]

CT your welcome, although that cold you had is going around - no returnsThat Stinks

Best
J:)

[He Who Shall Not Be Named]

As to gluing the acid-etched parts to the GRP:

Don't remove the photo-resist film from the metal parts (the film is an artifact of the acid etching process and has a high pH, making it the perfect substrate against which to stick the CA). Press fit the metal part into a GRP hole, align, then drop in some thin formula CA from the inside of the GRP structure. Let capillary action carry the adhesive around the joint between metal part and GRP. From the inside sprinkle baking soda to cure and build up filler in any gaps.

Apply more CA from the inside of the hull and continue to build up the baking soda foundation -- you want the strength: Whenever you use the gas blow, a large differential pressure is momentarily created and weak acid-etch part unions will fail and you'll 'blow' the part off the GRP and down it goes to Davy Jones Locker, never to be seen again.

Before any primer goes down, wet sand all GRP and resin parts with #600 sandpaper. Soap and water is a good start, but a greeny-pad scrubbing with lacquer thinner followed by the sanding is the only way to insure a solid adhesion between primer and parts.

I have spoken, so let it be written!

David,

[ConcreteTurtle]

As it is written so it shall be done. (Just as soon as I can get down to the local hardware supplier and grab some thinner). Thanks as well for the great advice on attaching the photo etch parts, I would never have thought of that.

Well, it's been a long week at work unfortunately, so this is the first chance I've had to update on the slow progress.

All the remaining limber holes are now opened up, and I'm beginning marking up the holes for the remaining grilles and mesh penetrations. This brings up a problem that I've found...

When I lay the hull on the plans, the width of the hull is about 1/4 inch less than what's drawn due to the springback of the GRP part.
Am I right in thinking that when I have the right rib profile opening the part, the hulls should match the plans? Or am I much better off shaping the supports by eye until I have a cylindrical cross section along the length?

Thanks Guys,

CT.

[ConcreteTurtle]

I also had the pleasure of dropping in on John again this past weekend to buy his 1:72 Thor designs Alfa kit and custom sub driver 3.5 with snort pump to suit. John also kindly threw in some 6V SLA to try out and the Alfa cabal report from David, which has totally blown my mind. I only hope I can do something half as good.



The SD 3.5 really is a fantastic piece of engineering and I'm planning to use this sub driver to drive both subs, but will get the Vepr in the water first.
I'm also waiting on Wayne Freys fantastic book to turn up from Amazon before I tackle the sharp looking Alfa.



Don't they make a great couple?

So roll on the weekend, I'll clean, sand and attach the photo etch parts, and I hope to start getting ribs cut and straighten out the springback to boot.

Thanks for all the advice and encouragement guys, and a huge thank you to John for showing me through his workshop and running subs. (His Collins class will be a sight to behold once it's finished)

CT.

[ConcreteTurtle]

Time for another small update and a couple of questions to the group,

I got the hull cleaned up nicely in the end but I did get worried at how soft and easily scratched the gel coat became after a scrubbing with a green pad and lacquer thinner.
However after persevering and hitting it with some 1200 grit wet/dry sandpaper, all the orange peel texture is gone and things are looking sharp. Oh, me of little faith!



I re-scribed the panel lines with a reversed hobby knife where they had lost definition, and filled any voids or imperfections which showed up with some laminating z-poxy and micro balloons.



My next step is making up the ribs out of 4 or 7mm plywood, then coating them several times with the laminating epoxy until it's nice and waterproof.

How low in the hull should I be trying to get the 3.5" subdriver with the ribs? Am I right in thinking that it should be as low as possible to help with the ballasting later?
As for the longitudinal placement, can I guesstimate the location or do I need to wait until all my batteries and the rest of the subdriver equipment is ready and use a sling to determine the centre of gravity?

Otherwise, I've ordered an ADF, MERS switch, battery WTC and some snort tubing from caswellplating.com to complete the kit ou oft the subdriver, and once that all arrives I can get working on setting up the SD 3.5 in parallel with the hull.
Good times ahead.

Thanks to all for the help so far,

CT.

[KevinMc]

Hi Angus,

Given the choice, set the upper surface of your SubDriver at the same height as your waterline, which hopefully will leave a little space below. That way when your ballast tank is dry it's as high in the hull as you can get it to be (giving you the best stability you can get when you're on the surface) and you've got room below, or low around the sides, for additional ballast weights if required.

KMc

[He Who Shall Not Be Named]

... and longitudinally, put the center of the ballast tank at the hull mid-way point. Battery goes forward, you'll yank the c.g. back to the center of the ballast tank with fixed lead weight aft.

David,

[Subculture]

A chap I know built one of these boats up. He scratch built his own WTC using a 100mm diameter acrylic cylinder and a 500ml Engel tank for the ballast system.

He mounted the module so that it was just below the waterline, so it sat low in the boat, almost on the bottom of the hull, as the cylinders diameter is quite large. The first test run demonstrated it was very tender, it rolled like a greased pig- this boat is quite heavy topside- all that etched brass adds up.

We bunged some more lead in the keel, and that helped things along. He ended up placing quite a bit of foam in the top half of the boat. So much infact, that the top half parted company with the bottom half whilst underway- the two halves were held together by a ball catch, which worked well on his other boats, but in this case the upthrust from the buoyant foam was sufficient to create a problem.

With a smaller cylinder like yours, you could run a battery pack underneath the WTC. This is what Sheerline did with their Trafalagr kit, and it transformed the boats handling. You need to use cylindrical cells for this- nicads or NimH, if you're using bulky lead acid batteries then you have very little choice where to put the batteries.