Assembling the Merriman 2.5" Standard WTC

[roedj]

I have acquired a 2.5" Standard WTC from Caswell to replace the 3" WTC which came with a 2nd hand 1/96 Skipjack. Problem is ... is that I can't find any clear instructions on how to assemble it. I can look at the old 3" model and figure out where some of the parts go but not all. I have downloaded the instructions for the 3.5 WTC and while it gives some help it just doesn't go into enough detail for a total newb like me. I have also looked at a Merriman narrated video but again just not enough detail.

So I figured why not just post it here and get help from any and all.

First up is pix of the old and new WTC...


As we can see the new 2.5" one is just about 1/2" longer...
... measuring the difference ...

Ordinarily this would be no big thing except in my case the original builder of the Skipjack cemented some foam in the nose which blocks the 2.5" WTC...
... I'll have to find a way to fix this.

Comparing the two motor end caps......
and battery end caps...

The ballast servo was out of alignment, I think...

I'm hoping I didn't just screw up some critical alignment by straightening it out...

This is an overall pic of all the parts received. By looking at the old 3" WTC I can identify some of them but there appears to be several changes that I'll need help identifying them all...


End of first post.

Dan

[roedj]

Individual parts

pictures of individual parts:

motor bulkhead - dry side... and wet side...

cylinder... and a mystery hole in the cylinder...

the gas saver...

"O" rings for ballast tank bulkheads...

the ballast tank...

push rods to connect servos to control surfaces...

supplied wire for motor and ESC...

ballast servo bulkhead - dry side... and wet side...

forward ballast bulkhead - wet side... and dry side...

battery bulkhead - dry side... and wet side...

air release valve -bottom... and top... and the valve placed in its location on the cylinder...

pin used as fulcrum for gas saver... and in the gas saver...

Kli-Cons... three sets are supplied.

extra servo mounting strap and extra hose...

adapter for Propel can...

SNORT manifold... mounted part way on motor bulkhead...

coupling to connect two push rods in different axes...

coupling to tie two push rods together in same axis...

unknown manifold although curvature suggests it should mount on outside of cylinder...

complete unknown...

plus screws (various sizes) extra socket screws, longer rod for gas saver(?).

That's the parts. Right now I have to say that the assembly order baffles me. I can see where the parts go based on my old 3" Sub Driver, but the assembly order is critical, I think.

Dan

[roedj]

No longer a mystery manifold

I think I've figured out one of the manifolds.

This one... can be used to route SNORT air into the ballast tank as well as direct air from the sail back to the other SNORT manifold... mounted at the rear of the motor bulkhead.

There's still that mystery hole on the bottom of the cylinder. Could this be the hole to mount this other manifold? I don't know as I'd rather mount this manifold on the top of the cylinder, I think.

I'm still working out the assembly order. I think I may have it - it ain't pretty but it should work.

Big problem now is trying to figure out how to mount the ESC, Li-Po guard, angle keeper, two servos, the receiver, the small SNORT pump and God knows what else on the miserably small supplied frame that's attached to the motor bulkhead.

I realize that Caswell and DM think this new 2.5" Sub Driver is really cool (lower CG, smaller parts and all that) but there's something to be said for lots of interior volume.

Dan

[roedj]

Reading the documentation - what a concept!

OK, flying in the face of my normal attitude that reading the documentation is for wussies, I actually located a contents list for this SD.

Turns out that the extra servo strap identified here... is in reality, and I'm quoting now, an on-board bottle restraining strap as demonstrated here... and here(shown not secured to the cylinder)......This also clears up the little puzzle of the mystery holes. They're for the strap..well duh.


The only item on the list of contents not accounted for is the -- switch cable strain relief block so I guess that that's what this is.... Yeah, whatever.

Also the part I identified as a coupling for two push rods... may, in fact, be a ---spare push rod watertight seal.

Now for the ESC's. I purchased a Mtroniks viper sub 10 ESC... and I'm sure that this is just a wonderful ESC. Trouble is, is that this sucker is just too big for the equipment tray for this SD especially given all the other #@%%$@ I have to install. I know Mtroniks makes a smaller version of this ESC called a Viper micro 10... which I have in another sub. It's much smaller. I've got to find this ESC. I'll try Caswell first.

Dan

[Kazzer]

I know Mtroniks makes a smaller version of this ESC called a Viper micro 10...[ATTACH=CONFIG]4351[/ATTACH] which I have in another sub. It's much smaller. I've got to find this ESC. I'll try Caswell first.

Dan

See the web page for Mtroniks

Look for the Micro or the Nano. Same thing, except the Nano has no epoxy or wires, making it smaller.

[roedj]

Mike,

Thanks for the lead.

In truth, I had already figured out that Caswell sold the ESC I needed. I was just wondering if anybody from the Caswell Empire was following this thread and watching me thrash about trying to figure this thing out. I figure I'd chum the waters a bit with the ," I'll try Caswell first," comment. Didn't take long for the fish to rise to the bait, LOL.

Dan

[Kazzer]

Mike,

I figure I'd chum the waters a bit with the ," I'll try Caswell first," comment. Didn't take long for the fish to rise to the bait, LOL.

Dan

"We only eat really distressed bait! You can suffer a bit more!" He says, spitting out the minnow!

[roedj]

Now I'm distessed bait

Someone,

Can someone confirm for me that this round black "thing" in the hole in the ballast tank bulkhead is, in fact, an "O" ring?... It sure looks like one to me but who knows?

I'm asking because I'm wondering if I need to use some sort of RTV sealant for the brass interconnecting tube or can I just rely on the "O" rings to keep the water out.

Dan

[He Who Shall Not Be Named]

See the web page for Mtroniks

Look for the Micro or the Nano. Same thing, except the Nano has no epoxy or wires, making it smaller.

Nooooo! ...

The Nano is only for the boats witha 1.25" SD!

David,

[He Who Shall Not Be Named]

Someone,

Can someone confirm for me that this round black "thing" in the hole in the ballast tank bulkhead is, in fact, an "O" ring?...[ATTACH=CONFIG]4352[/ATTACH] It sure looks like one to me but who knows?

I'm asking because I'm wondering if I need to use some sort of RTV sealant for the brass interconnecting tube or can I just rely on the "O" rings to keep the water out.

Dan

Dan,

Yes, both ballast bulkheads have this O-ring which effects the seal between bulkhead and conduit tube. The conduit tube is greased, not RTV'ed when slipped into the ballast tank space. It's the last item to 'slip' into place during assembly.

The strain-relief block glues to the inside face of the forward bulkhead and is drilled to pass the three wires between battery pack plug and mission switch -- it unloads the switch solder joints from any flexing as a consequence of battery handling.

David,

[roedj]

Dan,

The strain-relief block glues to the inside face of the forward bulkhead and is drilled to pass the three wires between battery pack plug and mission switch -- it unloads the switch solder joints from any flexing as a consequence of battery handling.

David,

David,

Which three wires? I can see switching one of the battery leads (+ or -) to effect an on/off condition but I don't get the three wires comment. Please explain.

BTW, good to have you back. I take it your presence here means thing are improving on the home front.

Dan

[roedj]

Greasing the "O" rings

The conduit tube is greased, not RTV'ed when slipped into the ballast tank space.
David,

What kind of grease do you use? Can I use this same grease to apply to the "O" rings to make it easier to slide the two ballast bulkheads into the cylinder?

The strain-relief block glues to the inside face of the forward bulkhead and is drilled to pass the three wires between battery pack plug and mission switch -- it unloads the switch solder joints from any flexing as a consequence of battery handling.

Also, I see where Caswell sells a waterproof switch, P/N BHWS, which is rated for 250V @ 2 amps. Do you recommend this switch to be used to turn the system on and off? I'm a little concerned because I think the current draw could be occasionally as much as 5 amps or more with all the electronics and the motor sucking current. I see a depression molded into the dry side of the forward end cap. Is this where you would install the switch? I'll also glue the strain relief block nearby too.

David,

I've made up a wooden tool to aid in the installation process. I'll show a picture later.

Dan

[roedj]

bulkhead tool + velcro

I've decide to use Velcro brand products to attach the various components to the equipment frame on the motor bulkhead ...... more on this later.

I've purchased the purest silicone grease I can find to lubricate the "O" rings......It's available in a lot of SCUBA dive shops.

The assembly procedure for the SD ballast tank has at least one "tricky" part which, hopefully, won't be so "tricky" in the end. It's the part where we attach the gas line to the gas bottle. I'm sure DM has worked this out long ago but I see only one way to do it. The problem is that I cannot turn the gas bottle inside the cylinder......it's just too bloody long. This means, I think, that the gas line must be attached externally to the cylinder and the only way to do this is to physically bring the gas line outside of the cylinder like this......I had to push the bulkhead forward of its normal position to get enough of the gas line outside of the cylinder. I also did not push the bulkhead so far forward that the "O" ring would be over the ballast tank hole for fear of nicking the ring. Note that for this demo I did not have the hose compression collar on the tube nor did I have the "O" ring installed on the bulkhead.

I've made up a tool...... to move the bulkheads around inside the cylinder. It's two pieces of 1/2" by 3/8" basswood glued to a piece of 1" by 3" milled pine. It just fits in the cylinder. With this tool I can push the bulkheads in and out of the cylinder...... because the tool is longer than the cylinder...... It can get around the gas bottle if need to be adjust a bulkhead....

Later, I'll show the actual assembly of the ballast tank.

Dan

[roedj]

Preparing the on-board bottle cylinder hole

With some behind the scenes advice from DM I've decided to enlarge the cylinder hole where the on-board bottle is placed.

First I sanded and filed the hole......the hole now looks oblong like this...... God, I hate the effects of digital photography. Every little scratch and oops really shows up.

"What did you use to make the hole bigger, klutz, a jackhammer?"

Anyway, I did it to allow me to turn the bottle inside the cylinder for the ballast tank assembly like this......then this...,,, and finally this......

I also had to deepen the "O" ring channel just a tad to allow me to actually get the bulkhead in the cylinder, like this...... be sure to use a nice sharp rat tail file and go slowly as a little filing goes a long way when you're only trying to remove a fraction of a millimeter.

Dan

[roedj]

correcting a color cast in the photos

I really don't know if anyone cares about this but I do so here goes. You may have noticed that I try and include a piece of white in most of my photos. That's not accidental. I do it to allow me to correct the green color cast caused by the fluorescent lights over my work station. I'm using Adobe Photoshop Elements 4. It's in the Enhanced menu under Color.

Here's the before...... and here's the color corrected version...

This is undoubtedly more important in nature and people photos but what the hell...

Dan