u-47 - diving problems

[magpie]

Hi Mark

Have you thought of

[color=#0000FF]Hi Mark

Have you thought of using a wet servo for the bow planes? I put a servo under the sail in mine with the control wires running back through an extension to 3 brass pins through the end cap and up to the (depth controller) to the receiver. You don't need the depth controller of course. It dives pretty well with the ballast tank set for decks just out. AS the guys have said, you need her low to dive dynamically. Bow planes on full down will help though. The servo is coated with silicone and has a rubber o-ring under the round servo horn to keep water out. I've had no water get in after many, many sails of her over 7 months since the build finished. There are pic of all this on my site at http]

[boatbuilder]

Hi Jason

Ive seen your web

Hi Jason

Ive seen your web site & found your work very impressive. Ive thought about a servo for the bow planes but hadnt worked out on how to run the wire from inside the pressure tube to the servo & to avoid any leaks. I`d thought of using the bellow thats used for the switch but found it to be a pain when want to separate the sub. Would you send me some pictures on how you fitted your servo. Thanks


mark

[Guest]

To run the servo wire,

To run the servo wire, why not run it in some flexible rubber tube. Fit some brass tubes at each bulkhead for the tubing to push onto.

Andy

[boatbuilder]

Hi

Can anyone tell me

Hi

Can anyone tell me if there`s a kit to add detail to my sub or do I have to make every thing from scratch.


mark

[boatbuilder]

Sorry folks I forgot to

Sorry folks I forgot to mention the detail I want to add is in the top of the conning tower.


mark

[boatbuilder]

Hi All

Ive managed to

Hi All

Ive managed to get my sub in to a fresh water lake instead of one filled with salt water. The sub sat lower in the water with the desks awash but the problem is Im still having problems getting the sub to dive. Could it be the way im contolling it or Should I add more weight & if so how much? the weight thats already fitted weighs 1250g. Should I just go for broke & invest in a static dive system that will eliminate all my problems. Is there anyone that is selling one or know where i can get one at a low price.


mark

[Guest]

Getting a U47 to statically

Getting a U47 to statically dive is straightforward, and need not be expensive.

Many have used an Engel tank, which works very well. However this will cost you at least £150 for the tank and electronics.

A simpler alternative is to make saddle tanks from bicycle inner tubes, and use a small air pump mounted in the pressure hull to inflate and deflate them.

That having been said, you shouldn't really be experiencing much difficulty dynamically diving the boat with decks awash.

[raalst]

to dive dynamically you need

to dive dynamically you need :
0) good waterline : you tell us the boat lies a bit low in the water, that is good.
1) forward speed -> check your speed. any friction in the drive train ?
2) dive planes moving enough -> check max deflection of those
3) as little as possible in the tower that takes up volume. can the air escape from the tower while diving ? is the tower filled up with something ?

indeed dynamic diving should be no problem, although there were more reports about needing un-scale-like speeds to submerge.

still another thing to watch : do the props surface while you dive ?
in that case you loose speed and the boat fails to dive. in such a case the
initial angle of the dive is too steep, and you should operate the dive planes a bit more subtly.

good luck testing !

[magpie]

Hi Jason

Ive seen your web

Hi Jason

Ive seen your web site & found ............................................

mark

Hi
Sorry for the delayed response.
I ran my servo wires through the end cap via brass rods of about 20mm with the wires soldered on each end and glued into the cap in a triangle of about 10mm. I coated it all with epoxy and painted it to look OK. I ran the wire up over the top with a plug to let the WTC come right out and enough slack to let it come out just enough to get to my switches and charge jack etc. The servo is silicone coated and has a rubber o-ring under the round horn and works well like that.
Jason
(Pic attached)

[bob_eissler]

On their type 21, Robbe

On their type 21, Robbe has you drill a hole in the top side of the WTC, take the wires out of the connector temporarily, and insert them thru.
Then seal up with epoxy or RTV around the wires-seems to work fine. If I built the sub again, I would just have the bow servo in the front of the WtC in a push-push type of arraingment so there would not be any connection to make when closing up the WTC. After I built the sub I reread an old SCR and Skip Assay had a couple of articles on how to do it with the old Robbie Shark sub.

[boatbuilder]

Thanks for the advice guys.




Thanks for the advice guys.


mark