Converting a petrol-powered strimmer into an outboard.

Pete.Dakota · 5 May 2011 at 16:19

I can't believe I have a relevant post to make in this forum.

Me and my friend acquired a boat, and here it is:

My friend also has a spare 21cc petrol (maybe diesel?) powered strimmer that he thinks we can convert into an outboard. Obvious problems:

- Rotating the driveshaft 45 degrees: This I believe is beyond us, and we'll probably have to mount the motor in the boat horizontally with the shaft aiming out the back.

- What do we use for a prop: In true DIY fashion, we don't want to part with any money and only use what we have. I'm thinking an 10 inch room fan blade. I'm not sure how similar the shape/feathering of fan blades and outboard prop blades are. However as you can tell by the size of the boat, we don't exactly need ludicrous power/efficiency.

- Noise: it's a very loud engine, we'll probably need to house it.

I'll come back with pictures of the motor when I can get them in a few days. But as an idea, do you think it's doable?

Ranger07 · 6 May 2011 at 07:22

It would be a lot easier buying an old outboard, even a brand new Suzuki 2.5hp isn't much more than £300 so a 10/15 year old one should be cheap enough.

Theres loads on eBay ranging from about 35 quid, most are collection only mind you.

Nightglow · 6 May 2011 at 09:48

What about an eletric outboard, pick them up on Ebay for around £150 (New), SHAKESPEARE SIGMA 54FT/LB Thrust ,£144:99p + p&p £7, they are quiet, all you need is a battery.

I bought a used one for £57 of Ebay back in January.

Nightglow · 6 May 2011 at 09:53

Woops double post.

Amp34 · 6 May 2011 at 13:11

5000RPM engine...
Bodged blade...

Nothing can go wrong here!

byteagig · 6 May 2011 at 13:27

I'm no expert, but I don't think a plastic propeller would last very long before it self destructed!

joey1211 · 6 May 2011 at 13:37

Amp34 said:
5000RPM engine...
Bodged blade...

Nothing can go wrong here!

lol. This has Darwin Award written all over it.

Amp34 · 6 May 2011 at 14:31

Haha, yep!

Don't get me wrong, done properly it would probably be fine, but if the fitting of the prop is not spot on (and weighted properly) it will shake itself to bits in seconds. You may also want more torque so some kind of gearbox assembly between shaft and prop?

iraiguana · 6 May 2011 at 15:37

Plastic prop I suspect as above the integral strength will not be able to handle high speeds in higher viscosity medium such as water.

Balancing and attaching said prop, no simple task as 5000rpm quickly will destroy anything you try.

£35+ for the bay of e special is by far and away your best shot here!

slylittlefox · 6 May 2011 at 17:01

That's a quality boat, jealous

How much?

DM · 7 May 2011 at 10:01

Stick to rowing that

Sone · 7 May 2011 at 10:07

needs a pulse jet

Amp34 · 7 May 2011 at 17:45

Sone said:
needs a pulse jet

Now that would be awesome. Buy one of those mini jet engines and attach it tithe stern.

DRZ · 19 Jun 2011 at 14:30

How did this turn out?

Nightglow · 19 Jun 2011 at 15:12

Sunk without trace...

Amp34 · 21 Jun 2011 at 00:06

Actually I think they found the answer to "will it blend..."

DJMK4 · 21 Jun 2011 at 09:44

I think this is a good idea

Why not? its a bit of fun.

It will either work, or it will be a epic fail, but still a laugh to try

Wassnt · 24 Jun 2011 at 22:52

As soon as your prop starts turning you're boat will spin out of control.

AndyOcUK · 26 Jun 2011 at 22:42

Amp34 said:
5000RPM engine...
Bodged blade...

Nothing can go wrong here!

agreed.

Get yourself busy with a mast, sail, tiller and rudder

A.N.Other · 27 Jun 2011 at 10:26

Amp34 said:
Actually I think they found the answer to "will it blend..."

Genuine giggles.

On topic, though ... 1) the fan would simply rip off if used in water 2) if it stayed on, the motor and gearing isn't designed for that sort of use and would not enjoy it.