Got a Spare Prop for your boat?

[kmclemore]

If not, you may want to consider a 3D printed one to get yourself home. I know, it sounds crazy, but it's been done... and tested! Yeah, you won't be going full crank on the way home, but you'll get home. It's a pretty inexpensive option to keep aboard in the event of a catastrophic prop strike.

https://youtu.be/a7QmpCS4RAI

https://www.thingiverse.com/thing:3118783

[OverEasy]

Hi Kmclemore

Interesting! Now that is a great idea for a spare prop as you suggested to get one home after a catastrophe.
Light weight and corrosion resistant…and if one has access to a 3D printer could be a nice project…or niche hobby business.

Kind of like that one could also color the prop too!
Adds a bit of extra visibility or artistic flare for those so inclined.

Best Regards
Over Easy

[Russ]

Very cool. Now I have a reason to buy a 3D printer.

[Piddle and Futz]

I would not have believed it possible if I had not seen the video... seems pretty nuts given the forces on a prop.

I noticed that one of the comments on that video recommended 3d printing in polycarbonate and then resin or epoxy coating for increased strength. PC is a bit tougher to print than your typical PLA, requiring a heated chamber.

Also found this older video comparing prints in 3-4 different materials.

Polycarbonate ended up the winner on that comparison as well. The videos are 4 and 6 years old, so there may have been advances in materials since then.

Just for kicks I loaded up the design at Shapeways to see what they would charge to 3d print it. Their cheapest plastic would cost about double what a comparable aluminum prop would cost. Up to $6000+ to produce a steel one.

Fun to think about, but think I will stick to having a real backup prop on board.

[Be Free]

For us counting our pennies

https://www.ebay.com/sch/i.html?_from=R ... _PrefLoc=2

Amazing and very interesting but I can get a spare aluminum prop for my engine for under $100. Now that I think of it, I already have one out in the workshop .

[kmclemore]

A few thoughts in response to the comments.

The material used to make that 3D printed plastic prop probably costs about $15.00, and I’m being generous… it’s likely less.

A really good 3D printer costs about $400… and you’ll end up making so many things that it will easily return its cost in utility.

The prop is supposed to just get you home, so the maximum performance isn’t really at issue. If, as the testing shows, it will do about 2300 rpm, that’s more than enough to propel the boat pretty nicely.

A plastic prop won’t rattle, corrode or need any cushioning (that may also collect mildew), so it’s easy to store.

[OverEasy]

Hi Kmclemore!

I haven’t looked for awhile now but yeah, the cost of a good 3D printer has dropped a lot in recent years.
The software has also gotten better and easier to use for a low time or novice user too!
The other issue is with the learning of current compatible CAD software to design the parts one wants to make the widgets with.

None of that seems to be as big a hurdle as it once was though.
There are a lot of interesting and useful items, jigs, fixtures, tools and decorative items that a 3D Printer can generate!

The bigger issue is getting off my couch and working through my existing TO DO LIST !!!

If I can get my TO DO LIST down to 50% of what it currently is the Admiral wouldn’t mind me getting a new useful ‘toy’ to play with
(……but I first gotta get some of the bigger existing projects knocked off the list ).

Best Regards
Over Easy

[kurz]

Great info about the Prop out of the printer.

Have to say that I personally don't have a 3D printer so far.

BUT: For me it was not the way to go. First: I do have spare ones made of alu, so no need to go to plastic.

Second: If you stay on holyday trip with your mac... and first day YOU damage your prop... and next 2 weeks you have to struggle around with this baby plastic prop... don't know... If it is worth to give the space in the boat for it. A real one takes the same space...

And: I got one of my prop (and it was the final one to check the radio!!!) for just 50.-- used. So why go for this part that maybe cannot get all the power in the water ...

[Starscream]

I'm considering buying a 3d printer, and have a Prusa mini in my "cart" on their website. I just don't know if I'll get enough use out of it after the first few cool things I print, and I fear it will just end up gathering dust.

We carry a Piranha Composite prop and prop wrench in the starboard bilge, disassembled into the hub and blade pieces. It's nice to have an backup that doesn't take up usable space and doesn't add much to the overall weight.

[kmclemore]

I’ve got a Prusa Mini and I love it - best 3D printer on the market today. I’ve made quite a few bits that I then sell, and at this point it’s paid for itself 2x over.

[Ixneigh]

The engine is an important piece of gear on these boats. Everyone should carry an actual spare prop and the wrench. Even me. Which I’ve been meaning to buy one.

[OverEasy]

Hi Ixneigh!

Excellent point!!!….and that segways into a parallel topic related to spare stuff to have…..

Recently we had our new to us runabout/tender ‘Scrambled’ (circa 1991 SunBird 15 ft w/50hp Johnson) out for a quick before sunset cruise of the Beaufort SC estuaries…. Nothing much just a simple launch from the Port Royal public boat ramp for an hour then back up on the trailer to go home…

Ancient Greek Maritime Aside:
Q: Do you know how to make the Gods laugh?
A: Tell them your plans….

At the end of COWEN Creek where it meets the Beaufort River the engine quit. Fribble…..no spare plugs, no flares, no flashlight no …. Well you get the picture. Fortunately the cell phone worked and Our Tow Boat membership was current!
We dropped anchor so we didn’t drift out to sea, got our general location on Google Maps, got our exact Longitude &Latitude on Apple Maps, then called Tow Boat, and in reasonably short order Tow Boat arrived to fetch us back to the boat ramp and everything worked out except we now had to wait for the tide to come back in before we could load the boat onto the trailer. Small inconvience.

Moral of the story is that a water tight “spares box” is gonna get put together and attached to Scrambled just like we have for Over Easy.

The question is what actually comprises a relevant “spares box” content?
What we have on our list are:
> A ‘get me home spare prop/prop-nut/cotter-key/wrench combo
> Pliers/Combi-Screw-Driver/knife
> A can of spray starter fluid
> A manual Outboard pull cord
> A set of new spark plugs/wrench
> A mini FirstAid kit (with a Trauma Pad & Gauze Roll)
> A “Distress Kit” (Flag/Flares/Smoke/Sea-Dye/LED-Battery-Strobe/LED-Flashlight/Extinguisher/Space-Blanket/Sea-Anchor/water-bottle/energy-bar)

Now what else should go into those kits for OverEasy and Scrambled???
Any and all suggestions welcome!

Best Regards
Over Easy

PS: Yes, it was the first time I’ve ever been stuck ‘at sea’ due to an on water break down in my life … but now that task has been checked off the list

[Starscream]

Now what else should go into those kits for OverEasy and Scrambled???
Any and all suggestions welcome!

Assortment of fuses used on board, including the main automotive type fuse for the motor.
Ringdings, cotter pins, sail slug stopper, those little pins that go into the stay adjusters.
Always good to have a small assortment of nuts, bolts and screws.
We carry a NoCo lithium battery booster that charges via USB. Haven't needed it for us yet, but have assisted the coast guard on two local dead-battery rescue missions.
Fuel line, bulb, and connectors.
Fuel transfer pump or siphon. We carry a shaker siphon, only had to use it once on another coast-guard rescue mission of an out-of-gas pontoon.
Always good to have a voltmeter on board.
Wire cutters.
Spare prop (just to keep on topic)
Forestay pin
Something for seasickness (not usually in first aid kits). We tried the pressure bracelets ang ginger pills. Can't say either actually works, but neither have we been seasick.
Spare sunglasses
$100 in cash in case cards go overboard
A few latex gloves

Lots more, I'm sure, I'll check in the spring when I can find the boat again.

[Russ]

"Over Easy" and "Scrambled"

What did it turn out that killed scrambled's motor?

Good ideas for spares.
A boat engine guy told me that starter fluid on a boat is a bad and dangerous idea. I never thought about it, but I suppose so.

[OverEasy]

Hi StarScream & Russ!

Great Items to add to the list!
Especially the seasick stuff…I know how miserable it is! Something is better than nothing, at least it can let someone know you’re trying to help and can maybe let them think of something else for awhile.

As far as Scrambled’s engine goes….it’s still an ‘Idunno’ item…working on it….🫣

Best Regards
Over Easy