The Great $80 RC Submarine Challenge!

[redboat219]

How about using vertical thruster in lieu of ballast tanks to dive?

[Subculture]

I don't think that counts as variable displacement, it's still a form of dynamic diver, albeit using a thruster rather than flow over the hydroplanes and hull.

In fairness there currently exists a number of models out there that can get you into this hobby very cheaply. In less developed economies even those low costs can be prohibitive, but not in countries like the USA.

I think the main problem lies is in skill set and underpinning knowledge. Even with technologies like 3d printing and pre-moulded parts, anyone engaging in this hobby needs a decent understanding of limits and fits, correct use of adhesives and reasonable dexterity with hand tools, cutting, filing, drilling etc.

[Nathan]

I don't think that counts as variable displacement, it's still a form of dynamic diver, albeit using a thruster rather than flow over the hydroplanes and hull.

In fairness there currently exists a number of models out there that can get you into this hobby very cheaply. In less developed economies even those low costs can be prohibitive, but not in countries like the USA.

I think the main problem lies is in skill set and underpinning knowledge. Even with technologies like 3d printing and pre-moulded parts, anyone engaging in this hobby needs a decent understanding of limits and fits, correct use of adhesives and reasonable dexterity with hand tools, cutting, filing, drilling etc.

All of which can be learned - I know I still have a lot to learn!

[Subculture]

There's always a new skill or challenge in this hobby.

I'm guessing that Bob is hoping to attract a few new faces by getting some inexpensive designs out there for people to build, or perhaps it's simply curiosity I don't know.

[RCSubGuy]

Sorry for the delay, everyone. It's been a hectic couple of weeks between work, travel and Renee's new chemotherapy regime. I leave again tomorrow for a week to FL, but should be able to get my brain wrapped around some of these questions and issues. Here is a summary of the questions that it looks like have cropped up and I will answer as soon as I can:

1.) Impartial judge(s)
2.) dynamic divers allowed? Perhaps that can be a different category with a smaller prize...?
3.) Start time?
4.) Pro rata parts (taking into account bulk pricing)
5.) Used parts?
6.) Full contest category list
7.) prize list

[RCSubGuy]

I just updated the first post to reflect further clarification and judging. Comments? Questions?

[Schmitty1944]

The updated rules sound excellent. I wish the cosmetics where worth more points but I think I understand why they aren't. A dynamic diver is acceptable but will get an automatic 5 points less out of a possible 30, that seems very fare.

I can't wait to see what others come up with!
I hope everyone remembers to document their builds with plenty of photos and videos.

Jason.

[Scott T]

You may want to change the close date as this is when the water is hard to broach. Sea trials not available to everyone.
Or make it a two-part contest. Build and bath completion. Then Sea trial results.

Contest Close Date:

1. January 31st, 2026

Entry prize if acceptable might be 2-3 sessions of Dive Tribe for completed submarine.

[RCSubGuy]

Dang it! All you guys living up where water gets hard in the winter are screwing with my contest!

Good point. Shoot. So, do we postpone the whole thing until late spring?

[Subculture]

Probably a good idea- will give people time to gestate the designs.

[Subculture]

If you 3d print tooling to make a fibreglass hull, will that be classified as a 3d printed hull?

[RCSubGuy]

If you 3d print tooling to make a fibreglass hull, will that be classified as a 3d printed hull?

Good question. As 3D printing was used as an integral part of the construction, my ruling would be yes, it counts.

[TuptubBuilder]

Good question. As 3D printing was used as an integral part of the construction, my ruling would be yes, it counts.

I think this conversation highlights an important issue. The unit cost of a mass produced item like a 9g servo depends upon the quantity purchased. If I buy a batch of one hundred 9g servos, is the cost of using two for the contest sub 1/50^th of the batch purchase?

[RCSubGuy]

I think this conversation highlights an important issue. The unit cost of a mass produced item like a 9g servo depends upon the quantity purchased. If I buy a batch of one hundred 9g servos, is the cost of using two for the contest sub 1/50^th of the batch purchase?

Correct. Perhaps if a bunch of builders wanted to go in together, they could bulk buy some servos, ESCs and batteries and get the price down for everyone? Only issue would be shipping, which would kill the savings. Shipping $1 worth of servos would cost you $8, and, technically, that is a cost of building the boat, so....

[Schmitty1944]

Correct. Perhaps if a bunch of builders wanted to go in together, they could bulk buy some servos, ESCs and batteries and get the price down for everyone? Only issue would be shipping, which would kill the savings. Shipping $1 worth of servos would cost you $8, and, technically, that is a cost of building the boat, so....

I think this is where the impartial judge comes in. If you bought servos on Amazon prime and they where delivered for "free" do you count the cost of the Prime subscription? ($15 a month or $140 a year). Most states (USA) have to pay sales tax but some don't so does that count?

I think it's reasonable to buy parts cheap such as closeout or surplus items (servos, motors, pumps etc.) but you can't enter a $300 hull and say you bought it at a yard sale for $10. Models entered should be reasonably repeatable for the same cost. Isn't that the whole point of the contest?

Most people will understand the spirit of the contest and hopefully not just look for loop holes in the rules. But ultimately there should be a judge that decides what is or isn't acceptable and assigns a reasonable value to parts who's cost can not be proven.

Could Logan serve as impartial judge?

Jason.