Inability to keep the water out > Long distance rescue

[Reefmagnet]

Speaking of aussies and outboard motors modified to pump water, we (kind of) already invented that years ago. It was a "hamilton jet" tacked onto the bottom of a conventional outboard. Replaced the conventional gearbox and propeller and was designed to allow a boat to operate in shallow, muddy river water. Would be super easy to modify to a crash pump.

Then there's always the idea of modifying a jet ski drive...

[Juniper]

How about keeping afew float bags aboard and a way to inflate them, it'll keep the boat from sinking, say a box or two of these 36 x 48" Inflatable Economy Dunnage Bags S-8010 - Uline

then as long as the deck doesn't seperate

[minaret]

Originally Posted by Juniper

How about keeping afew float bags aboard and a way to inflate them, it'll keep the boat from sinking, say a box or two of these 36 x 48" Inflatable Economy Dunnage Bags S-8010 - Uline

then as long as the deck doesn't seperate

The deck WILL separate. This has been much discussed in the past, and there are commercial options. Unfortunately, very expensive, and it just doesn't make sense for any but the most paranoid.

[minaret]

Originally Posted by Reefmagnet

Speaking of aussies and outboard motors modified to pump water, we (kind of) already invented that years ago. It was a "hamilton jet" tacked onto the bottom of a conventional outboard. Replaced the conventional gearbox and propeller and was designed to allow a boat to operate in shallow, muddy river water. Would be super easy to modify to a crash pump.

Then there's always the idea of modifying a jet ski drive...

Seen these before. It would probably be super easy to modify one to work as a pump, no cowling required. Just a hose fitting on the jet intake. You'd need to prime the hose though. Would probably move a ton of water at WOT!

[Andrew Troup]

Originally Posted by minaret

Seen these before. It would probably be super easy to modify one to work as a pump, no cowling required. Just a hose fitting on the jet intake. You'd need to prime the hose though. Would probably move a ton of water at WOT!

This is the best idea yet, I reckon, for boats which would be carrying an outboard motor anyway (which is obviously most)

The same motor would make a safer option for kids fooling with improvised waterskis or whatever around the stern of the mothership's dinghy

You'd think for a fairly low output motor, infrequently used, the housing at least could be a reinforced engineering thermoplastic.

And although petrol motors are less than optimum on a cruising boat, at least this is one which is already likely to receive constant attention and maintenance, so there's little extra burden on that score.

There is a local story/myth about a farmer somewhere up the Clarence whose isolated homestead was at risk from an outbuilding catching fire. The fire pump threw or had thrown a rod, depending who tells the story.

So (the story continues) .... He dumped the Hamilton jetboat into the rudimentary swimming pool behind said outbuilding (in some versions he didn't even untie it from the trailer) and presumably quickly rigged a couple of lines to hold the arse end up and a couple of fore-springs to assist with the "point and shoot", (and put the handbrake on the 4WD, perhaps, or not, as the case may be)

12000 gpm later, the outbuilding was not just extinguished, but demolished. Problem solved. Now he only had to work out how to remove the jetboat (and, in some more lurid versions, the 4WD) from the somewhat emptied pool.


This probably should be in the Bad McGyver thread ....

[Lojanica]

The snap on pump housing on an OB is a great idea for many reasons. OB is already bought and paid for, rigorously maintained at least one would hope, the prop would chop the hell out of debris, and would be cheap.

The problem is it would be hard to find a big enough market to make it worthwhile although with 3-d printing and cad/cam it wouldn't be that hard to make molds for thermoplastic, abs or nylon.

[bornyesterday]

Assuming the idea works as hoped then a fun youtube video would probably sell them faster than I ( oh, all right then, we) can make them.

Main problem I see is the number of different outboard models to be catered for.

We need to sell the idea to a manufacturer quick - before anyone notices it's not patentable

[minaret]

Originally Posted by bornyesterday

Assuming the idea works as hoped then a fun youtube video would probably sell them faster than I ( oh, all right then, we) can make them.

Main problem I see is the number of different outboard models to be catered for.

We need to sell the idea to a manufacturer quick - before anyone notices it's not patentable

No way, open source that sucker instead. Just need a CAD drawing of the part for each model, 3D print a mold for fiberglass. Then each can make their own.

[bornyesterday]

Just in case anyone is actually serious about trying this - I'd suggest the housing's bracket should be held to the (dinghy's etc.) mounting plate by the outboard's own clamp. Ought to be possible to make that an almost universal fit.
Good luck

[Andrew Troup]

I think the biggest difficulty (without thinking deeply about it, and without pretending it's a showstopper) would be sealing the pump housing around the o/b leg.

(Haven't thought deeply 'cos I consider o/bs, at least petrol ones, to be the devil's childer, but that's a very minority view, so it's still an interesting suggestion even to me)

As a second-best option (I think the jet unit is the best) perhaps some might consider a pump which *replaced* the prop, the housing prevented from turning by a torque arm, in the same was as shaft-mounted industrial gearboxes? This could be a great deal more efficient

Furthermore, even more than Minaret's jet unit, it would be self priming and consequently could remain on its clamp on the transom, which is (to my way of thinking) as close as it should ever get to the interior.

[minaret]

Originally Posted by Andrew Troup

I think the biggest difficulty (without thinking deeply about it, and without pretending it's a showstopper) would be sealing the pump housing around the o/b leg.

(Haven't thought deeply 'cos I consider o/bs, at least petrol ones, to be the devil's childer, but that's a very minority view, so it's still an interesting suggestion even to me)

As a second-best option (I think the jet unit is the best) perhaps some might consider a pump which *replaced* the prop, the housing prevented from turning by a torque arm, in the same was as shaft-mounted industrial gearboxes? This could be a great deal more efficient

Furthermore, even more than Minaret's jet unit, it would be self priming and consequently could remain on its clamp on the transom, which is (to my way of thinking) as close as it should ever get to the interior.

Could be a sharp idea. You'd just remove the prop from the outboard and bolt on the crash pump. Could be done quickly. I bet you could make a set of adaptors for your pump that would even allow it to accept different shaft sizes for different outboards.

[Andrew Troup]

Indeed, Minaret, you're onto it, I reckon.

Make the bore significantly bigger than the biggest shaft, to accomodate all motors, including those as yet unborn, and allow for a realistic wall thickness even in the largest adaptors

Instead of a torque arm there could be an arch, slotted each side, to fit over the anticav plate. (Several lots to accomodate various offsets of plate from shaft)

[Reefmagnet]

This is what an outboard powered hamilton jet looks like

[Andrew Troup]

Originally Posted by minaret

The deck WILL separate.

Hmm - I guess you would concede the point for metal boats?

A few cartons of those cheap dunnage bags, and a dinghy inflator pump, would not (I think) be entirely without merit for such a boat.

It wouldn't be a major if a few got punctured over time...

[goboatingnow]

Originally Posted by Andrew Troup

Indeed, Minaret, you're onto it, I reckon.

Make the bore significantly bigger than the biggest shaft, to accomodate all motors, including those as yet unborn, and allow for a realistic wall thickness even in the largest adaptors

Instead of a torque arm there could be an arch, slotted each side, to fit over the anticav plate. (Several lots to accomodate various offsets of plate from shaft)

How would the water supply be provided to cool the engine,

Furthermore it would be a very large pump. Given the relative gearing, al in all a beast to move around the idea of a cowl or something is certainly " left field " I wonder if you'd really shift any amount of water

My local Aldi had crash pumps recently for 150 quid, I think.

Dave


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