The Great $80 RC Submarine Challenge!

[Schmitty1944]

I'm in.

Jason

[Nathan]

I have a design in mind. Static diving and all.

[Subculture]

Perhaps we should get a show of hands of those who will be participating?

I'll throw my hat in if dynamic divers are included.

[Schmitty1944]

I think this contest needs an impartial judge/mediator who can decide some of these questions and whom can be consulted with regarding acceptability of builders choices.

This Judge could also take certain factors into account when they pick a winner such as whether the builder scratch built everything or used a $1000+ 3-D Printer or CNC machine etc. I have someone in mind, but I don't know if they might want to be in the contest and I can not mention their name.....

Jason

[Subculture]

Regarding materials, are costs going to be calculated pro rata?

Many parts have to be purchased in minimum quantities often in excess of which is required for a single build, leaving parts left over for other projects e.g. pipe, connectors, wiring, linkages, resin, seals etc.

Will all parts have to be new, or can secondhand/used/scrap material items be incorporated?

Also inclusion of a ballast system is simple enough, however seems somewhat restrictive if the original boat didn't have one, and dynamic divers can be just as much fun as static divers.


Final point, will designs have to original e.g. no use of others STL's/3d cad or pre-made hulls.

[Nathan]

Does the 60 days include ordering and shipping or can (and should!) we start that now?

[redboat219]

Why not? They're part of the sub, and a vital one at that...

Think disposable batteries like alkalines, $1 per piece. 5-6 pieces of AA batteries to make 7.4v.
The sub only has to travel 30ft. 15 ft forward turn then travel back 15ft.
To conserve power ballast venting needs to be passive. Ballast blowing can either be thru water pump or snort/ low pressure blower. Gas like Propel would be least power hungry. Limit to 1-2 blows

[RCSubGuy]

Good question! Should not

Why not? They're part of the sub, and a vital one at that...

[biggsgolf]

Do batteries count as part of the build materials?

Good question! Should not

[Fishb0y]

Do batteries count as part of the build materials?

[redboat219]

plastic model kits like Trumpeter Seawolf or PVC pipe for hull/ wtc with plastic easter egg halves for the bow and stern cone.

[TuptubBuilder]

Can I start with a 20 USD Tamiya Blowfish?

[Subculture]

Perhaps consider bonus points for those substantially coming under budget?

3d printed hulls fair enough, but perhaps not the first thing available to someone on a tight budget (build a cheap sub, but first buy this $200-300 machine....). Perhaps cost for printed hull could more accurately be reflected by bureau rates, realistically $20+.

[Fishb0y]

OOF, I love this!!!

[RCSubGuy]

The Great $80 Submarine Contest

Build a complete RC submarine, but do it for less than $80US!

Contest Close Date:

1. January 31st, 2026

The Sub:

1. Build must be executed, entered and documentation submitted to the judge(s) by contest close date.
2. Total budget of any and all materials and components, not including the radio and receiver, is to tally up to less than $80US.
3. Any components not purchased specifically for the project (IE: you just had them lying around for the last few years) will be assessed a fair market value. Used parts fall into this category and will also be assessed fair market value based on new parts pricing.
4. Parts sourced in bulk can use the per piece pricing (IE: 10pcs at $10 would be $1 each)
5. The submarine must be controlled wirelessly. No tethers allowed.
6. The submarine should have a functional ballast system capable of taking the boat from surfaced condition to submerged condition and back to surfaced condition.
   1. Surfaced means at least 10% of the total hull above the waterline
   2. Submerged means the entire hull below the waterline. Having a small amount of sail protruding, along with masts/scopes is acceptable
7. Dynamic diving submarines are allowed, however they will be penalized points compared to a full static diving boat.
8. The submarine should be capable of movement in both forward and reverse. Forward movement only is allowed, but a points penalty will be applied.
9. The submarine must be capable of transiting in submerged condition for a distance of at least 30ft (9m) without surfacing
10. The submarine must be capable of executing a 360 degree turn in an area of less than 20ft (6m) diameter / 10ft (3m) radius
11. 3D printed hulls are allowed, but a points penalty will be assessed.

Winner Requirements:

1. Provide receipts of all components and materials used
2. Must pay shipping from TX, USA for any prizes awarded to them
3. Must fully document the components used
4. Must provide photos and/or video of the build process (to help others follow in their footsteps for the build).
5. Lack of any of the above requirements results in disqualification from prize awards.

Prizes:

1. 1/96 Los Angeles fully RTR sub
2. Additional prizes to be announced.

Submarine Evaluation: Highest points tally wins. Maximum score: 30 points

1. Price: 10 points maximum
   1. Below $80: 10 points
   2. Above $80: -1 point for each $2 above $80 (IE: If cost is $90, -5 points)
   3. 3D printed hull: -2 points
2. Performance: 15 points maximum
   1. Movement forward and reverse: 2 points
   2. Forward movement only: 1 point
   3. Submerged operations for a minimum of 30ft: 5 points
   4. Ballast system transitions boat from surfaced to submerged trim: 5 points
   5. 360 degree turn in less than 20ft: 3 points
3. Cosmetics: 5 points maximum
   1. Impartially rated with a score of 1 through 5 points