Outboard in Well

[LONG_KEELER]

The other thread on blanket noise reduction reminded me about something.

I've been messing about this season trying to reduce the sloshing about of water in the well when underway , both as a go faster measure to negate the disturbance
and help with the water noise.

Recently, I have tried two small wheelbarrow inner tubes looped over the outboard leg then inflated . This filled the outboard well quite nicely and has helped with the sloshing a bit. A surprise benefit is the lessening of both noise
and particularly vibration from the engine. I assume that the buffer of inner tube between leg and boat is a dampener . I have no idea how long the inner tubes will last as the outboard leg has a number of fairly sharp bits poking out
and the tracer from the water pump does seem to get a bit warm.

Anyone else tried this or can the forum see any other problems.

If successful , should I get some square tubes made up and start flogging them to inboard engine owners. Green for Volvo etc

 

[Seajet]

The thing to watch is are the engine coolant inlets free and unobscured ?

My Anderson 22 has an outboard well as standard; the normal drill is to get out of harbour into clear water then lift the engine out, give it a few seconds to drain then stow it in a locker ( taking care of attitude if 4 stroke ) then a fairing plug is put in the well to give a smooth drag free hull, the prop' can't pick up weed or lobster pot lines.

When the engine is out and the well is empty the noise and turbulence is surprising, one couldn't tolerate it for long without the fairing plug.

Some people have tried things like the engine in permamantly with a fairing plug surrounding the outboard leg and nylon brush bristles around the gap but this caused overheating - may be a particular engine would work but that one didn't.

For a boat around 18-24' an outboard in a well remains the best option in my view, zero drag and vastly increased cruising speed - thus range - when the engine is out, and if any work is required on the engine simply take it ashore - which compares very favourably with the hassle, weight, space taken up and expense of an inboard.

 

[wallacebob]

What an interesting idea. My Hunter Lib 22 has terrible outboard noise/vibration at anything above tick over due to the Outboard well design. Lifting out is not an easy option, and the hull tunnel design is fairly good: drag is an issue, but tolerable. This idea will be number one on my list next season to reduce noise.

 

[Seajet]

wallebob,

is there an owners association where you might get a well fairing plug ?

 

[Heckler]

The other thread on blanket noise reduction reminded me about something.

I've been messing about this season trying to reduce the sloshing about of water in the well when underway , both as a go faster measure to negate the disturbance
and help with the water noise.

Recently, I have tried two small wheelbarrow inner tubes looped over the outboard leg then inflated . This filled the outboard well quite nicely and has helped with the sloshing a bit. A surprise benefit is the lessening of both noise
and particularly vibration from the engine. I assume that the buffer of inner tube between leg and boat is a dampener . I have no idea how long the inner tubes will last as the outboard leg has a number of fairly sharp bits poking out
and the tracer from the water pump does seem to get a bit warm.

Anyone else tried this or can the forum see any other problems.

If successful , should I get some square tubes made up and start flogging them to inboard engine owners. Green for Volvo etc

Just be aware there have been issues with exhaust build up causing engines to stop from lack of oxygen and I would hate to think of it stopping a life!

 

[ShinyShoe]

Just be aware there have been issues with exhaust build up causing engines to stop from lack of oxygen and I would hate to think of it stopping a life!

Outboard normally takes air in at cowling so above the tyres the OP describes and most eject exhaust through the prop I think. So into the water - below the tyres... Or out at the cowl...

I'm not seeing any exhaust hazards.

Presumably the tyres are above the find that are above the prop? So should be above the water intake too?

Where does the "pee hole" water go?

 

[doug748]

What I ended up with was a long waterproof fabric sock, filled with light foam. I wrapped this, like a cumberland sausage, under the power head and crammed it down. It was a little bit of fuss but did keep out quite a bit of water/noise/fumes.

A blanking plug is nice but not always appropriate. Also, if the bottom of your well is below the waterline, your plug will always have water over it and this will always be refreshed and be dumped in the lazarette in poor conditions.

 

[rwoofer]

I prefer my outboard off the back. Less noisy, less space, but does suffer when motoring into chop. As always it's the compromise that best suits you.

 

[Seajet]

I suspect there's a language difficulty here.

On my boat it's either the engine or the well fairing plug in situ, an arrangement which works; err well.

For boats leaving an outboard in a well all the season along with anodes they should try to have a smooth hull beneath but a decent water cooling inlet - as a guage isn't possible I put my hand under the water outlet telltale every few minutes.

 

[wallacebob]

wallebob,

is there an owners association where you might get a well fairing plug ?

Very good Assoc: HLMOA.org.uk. The “well” is a very clever design: a faired ”tunnel”in the hull leads to the well, with twin trailing edges - poor description - that is meant to reduce the drag. The design is mainly because Hunter Liberty and Minstrel have a round stern. KTL had several discussions on outboards. The design also gives great straight line stability, and outboard steering control as the water is forced over the rudder. Almost impossible to fit a fairing plug due to complex hull shape.

 

[Heckler]

Outboard normally takes air in at cowling so above the tyres the OP describes and most eject exhaust through the prop I think. So into the water - below the tyres... Or out at the cowl...

I'm not seeing any exhaust hazards.

Presumably the tyres are above the find that are above the prop? So should be above the water intake too?

Where does the "pee hole" water go?

Some of them eject exhaust halfway down the leg as well.

 

[LONG_KEELER]

What I ended up with was a long waterproof fabric sock, filled with light foam. I wrapped this, like a cumberland sausage, under the power head and crammed it down. It was a little bit of fuss but did keep out quite a bit of water/noise/fumes.

A blanking plug is nice but not always appropriate. Also, if the bottom of your well is below the waterline, your plug will always have water over it and this will always be refreshed and be dumped in the lazarette in poor conditions.

I do have a blanking plug, but lifting the outboard and putting it in a locker is just not
practical for me. Apart from the weight and awkwardness I have a long trip to find the open sea. I sail when I can but narrowness , commercial traffic , and other yachties make the
engine always available. The 4 stroke is also considerably quieter and has a much longer
range than the 2 stroke. I did try a 2 stoke once but it set off my smoke alarm located in
the cabin despite being unable to see fumes.

Each to their own of course.

 

[coveman]

Some of them eject exhaust halfway down the leg as well.

That's correct - My Yamaha 8hp 2 stroke does exactly that - on my Etap it is solved by tapping into the rear of the engine leg. A flexible pipe is fixed to this and exits the transom - a standard Etap fitting, which solves the problem of exhaust gases building up in the well.

 

[Greenheart]

It sounds like an interesting practical DIY question, for any yacht with an outboard well.

I think the problem is the starting point which says that either the plug or the engine must occupy the well; and the assumption that if a hole is made in a plug for the engine leg to poke through, the engine must still be removable from the plug.

Assuming one buys an outboard with the expectation of using it for years, it might be worthwhile recreating the standard plug that fills the hole in the hull, but with a division right down the middle, such that it forms two airtight boxes with a central shaft-cavity, which can be bolted tightly around the shape of the engine leg, yet with lower surfaces that still completely plug the well.

The division behind the shaft must incorporate a narrow slot that cooling water can flow out through. But otherwise, the shape of the underside of the hull around the outboard's leg would be much like the flush, undistorted hull around a saildrive leg.

I've seen attempts to reduce the openings at the bottom of well-plugs, by cutting the smallest hole that the prop and ventilation plate can fit through. But they're not that tight a fit, and the hole still creates frothing and turbulence. If a two-part plug were bolted to fit exactly round the leg, it would minimise drag caused by the open well, without the outboard needing lifting out.

 

[coveman]

It sounds like an interesting practical DIY question, for any yacht with an outboard well.

I think the problem is the starting point which says that either the plug or the engine must occupy the well; and the assumption that if a hole is made in a plug for the engine leg to poke through, the engine must still be removable from the plug.

Assuming one buys an outboard with the expectation of using it for years, it might be worthwhile recreating the standard plug that fills the hole in the hull, but with a division right down the middle, such that it forms two airtight boxes with a central shaft-cavity, which can be bolted tightly around the shape of the engine leg, yet with lower surfaces that still completely plug the well.

The division behind the shaft must incorporate a narrow slot that cooling water can flow out through. But otherwise, the shape of the underside of the hull around the outboard's leg would be much like the flush, undistorted hull around a saildrive leg.

I've seen attempts to reduce the openings at the bottom of well-plugs, by cutting the smallest hole that the prop and ventilation plate can fit through. But they're not that tight a fit, and the hole still creates frothing and turbulence. If a two-part plug were bolted to fit exactly round the leg, it would minimise drag caused by the open well, without the outboard needing lifting out.

I would agree entirely with what you say - the "rubber" well plug supplied with the Etap does exactly what you suggest. It fits snugly around the outboard leg with a slit at the rear and a horizontal slot that the cavitation plate sits in. To remove the outboard you have to take out the outboard and bung together and then the bung can be taken off via the rear slit if required. There is also a small hole in one corner of the bung to allow any water to drain away( ie water from the tell tale)

It fits so that the underside is flush with the underside of the boat and as you say works in the same way that as a saildrive leg. I'm not sure exactly what the plug is made from - it would appear to be a very heavy duty rubber compound. These plugs were manufactured to fit an 8hp Yamaha 2 stroke leg so if the engine is changed some adaption would be necessary but the principal works very well.

I usually take the outboard out of the well complete with bung and store in the cabin when not in use and then replace in the well when I need it again - very simple and means you can easily take the engine home for maintenance if required.

 

[LONG_KEELER]

I would agree entirely with what you say - the "rubber" well plug supplied with the Etap does exactly what you suggest. It fits snugly around the outboard leg with a slit at the rear and a horizontal slot that the cavitation plate sits in. To remove the outboard you have to take out the outboard and bung together and then the bung can be taken off via the rear slit if required. There is also a small hole in one corner of the bung to allow any water to drain away( ie water from the tell tale)

It fits so that the underside is flush with the underside of the boat and as you say works in the same way that as a saildrive leg. I'm not sure exactly what the plug is made from - it would appear to be a very heavy duty rubber compound. These plugs were manufactured to fit an 8hp Yamaha 2 stroke leg so if the engine is changed some adaption would be necessary but the principal works very well.

I usually take the outboard out of the well complete with bung and store in the cabin when not in use and then replace in the well when I need it again - very simple and means you can easily take the engine home for maintenance if required.

Do you mean This (right hand side)

https://www.google.com/search?q=eta...UIEygC&biw=1405&bih=747#imgrc=uj-oF6ixmEEj2M:

First time I have seen a bespoke outboard insert on a boat with a well.

It's interesting as the insert is not split all the way i.e. two parts. I'm guessing that the insert is made of some kind of man made rubber.

 

[Redfox226]

Coveman
I'd be interested to know the dimensions of the plug; I wonder if it might be adapted to fit my Red Fox well....

 

[coveman]

Do you mean This (right hand side)

https://www.google.com/search?q=eta...UIEygC&biw=1405&bih=747#imgrc=uj-oF6ixmEEj2M:

First time I have seen a bespoke outboard insert on a boat with a well.

It's interesting as the insert is not split all the way i.e. two parts. I'm guessing that the insert is made of some kind of man made rubber.

Yes, that is it! David Morris still sells them ( he was an Etap agent) but he imports them specially and they come at a price - £200 last time I spoke to him! Having said that they are very tough and should last. I think the one I have is the original on a 1992 boat. If you push the split apart the engine can be taken out easily.

 

[coveman]

Coveman
I'd be interested to know the dimensions of the plug; I wonder if it might be adapted to fit my Red Fox well....

Hi, The dimensions are
41cm long
25cm wide
6,5cm thick including the lip which is approx. 15mm thick and surrounds the plug which rests on the ledge at the base of the well.
The slot for the engine leg is approx. 18cm long but the plug slot is quite intricate in that their is an angled slot within in to perfectly match the cavitation plate on the engine.
I would think it would be quite difficult to adapt it for an alternative engine unless there was a very close match.

 

[Redfox226]

Thanks Coveman - won't fit... I think I'll try closed cell neoprene, and glue sheets together. 'Tis an electric outboard, so I don't have to worry about cooling.