Prop guard idea

[robkg]

Whilst I am not one to dwell on safety, I do always have a slight concern about one potential risk.

Namely the risk of falling in off the stern whilst the boat is in reverse and immediately getting dragged into the prop.

We have two children (9 and 11) and generally only allow one at a time on the counter and not at all when manouvering.

 

It has occured to me that it might be possible to attach three or four curved steel bars on each side, in a horizontal plane, from just behind the start of the stern swim to the vertical steel post (sorry I don't know the proper name) attached to the skeg and in front of the rudder. I think they would need to be very robust (1" x 2" solid bar) and may need additional vertical bars tying them together at regular intervals.

 

The bars would then be about 6" to 8" apart. I am guessing that this would not create too much resistance to the flow of water and so not affect the boats efficiency or ability to swim.

 

I would expect them to have to be cleared of debris occasionally.

 

The advantage of course would be to deflect a person, stopping them from getting caught by the prop.

 

As this addition would be below the water surface, it would not be detremental to the boats aesthetics.

 

I have not as yet actually tried this idea but may consider it sometime in the future on 'Grace' if sufficient other people think it is a good idea.

 

What huge flaw have I missed?

[Malarky]

I think your demonstration of dicipline in the presence of danger, to the children, by your examlpe, and the spinning prop is the best solution, and will carry them in good stead; the prop guards will not.

[mayalld]

Whilst I am not one to dwell on safety, I do always have a slight concern about one potential risk.

Namely the risk of falling in off the stern whilst the boat is in reverse and immediately getting dragged into the prop.

We have two children (9 and 11) and generally only allow one at a time on the counter and not at all when manouvering.

 

It has occured to me that it might be possible to attach three or four curved steel bars on each side, in a horizontal plane, from just behind the start of the stern swim to the vertical steel post (sorry I don't know the proper name) attached to the skeg and in front of the rudder. I think they would need to be very robust (1" x 2" solid bar) and may need additional vertical bars tying them together at regular intervals.

 

The bars would then be about 6" to 8" apart. I am guessing that this would not create too much resistance to the flow of water and so not affect the boats efficiency or ability to swim.

 

I would expect them to have to be cleared of debris occasionally.

 

I would expect them to have to be cleared of debris with monotonous regularity, and I would suggest that the risks created during such clearances would far exceed the risk that you are seeking to mitigate.

[nb Innisfree]

Yes I too worry about this often overlooked or trivialised danger.

 

I think the vertical bar you refer to is probably the rudder post? which rotates so couldn't be used as a fixing point. Better I think would be vertical bars fixed/welded to the rear edge of the counter and joined together, in a radial pattern, to the skeg.

 

As for the risks entailed when clearing surely you would stop the engine as if working in the weedhatch?

 

Even better would be to have a device that puts prop into neutral when the tiller is released?

Edited August 12, 2009 by nb Innisfree

[RLWP]

As for the risks entailed when clearing surely you would stop the engine as if working in the weedhatch?

 

But as the stuff you are clearing will build up on the outside of the bars and you are clearing from the weedhatch, you'll have to pull the material through the bars to clear them. I doubt that you will be able to reach.

 

If you have fallen in and been drawn towards a moving propellor then will this device help? It will still chop off appendages that fit through the gaps, would hold a person underwater by the flow through the prop and if your clothing should pass through and stop the prop will make it extremely difficult to disentange you.

 

I also think the discipline that you are practising is a much better solution and covers more possibilities. If a child falls in, put the gearbox into neutral. Train a child to do the same if anyone else falls in.

 

What kind of stern does your boat have?

 

Richard

[Proper Job]

I think the concerns that Richard has raised would be the same as mine.

 

For such a device to be truly effective the spacing between the bars would have to be a lot smaller.

 

I not saying its a suggestion that shouldn't be explored, but I think if it were practical, they would be fitted already.

 

A few years back I was on the river Thames and the kids where swimming out to boats and hanging on to fenders to be dragged along. They swam out toward me (I didn't have fenders). I stopped the boat and switched off the engine. I then offered each one of them the chance to reach under the counter and feel the prop.

They were last seen swimming to the shore and not chasing boats any more.

 

Constant education of the dangers of boating to children (and adults) is always the first and most effective method in my book.

[koukouvagia]

I’d never thought of the ring round the blade on the hydraulic motor in our ellum as a guard, but I suppose it does serve that purpose. It’s there as an anti-cavitation device (I don’t want to start up the cavitation thread again – I can’t remember the details of that particular debate – but you know what I mean).

Things very rarely get stuck on the blade, mainly because the ring stops rubbish being sucked up from the bottom. If anyone were going to experiment with a blade guard, I suggest one arranged vertically from the skeg to the uxter-plate might be the way to go.

 

[robkg]

Yes I too worry about this often overlooked or trivialised danger.

 

I think the vertical bar you refer to is probably the rudder post? which rotates so couldn't be used as a fixing point. Better I think would be vertical bars fixed/welded to the rear edge of the counter and joined together, in a radial pattern, to the skeg.

 

As for the risks entailed when clearing surely you would stop the engine as if working in the weedhatch?

 

Even better would be to have a device that puts prop into neutral when the tiller is released?

The vertical bar that I am refering to can be seen directly in the photo in front of the rudder and doesn't move.

 

Your idea sounds like it has merit but may be a pain when changing steerers or using both hands momentarily for some other purpose.

 

But as the stuff you are clearing will build up on the outside of the bars and you are clearing from the weedhatch, you'll have to pull the material through the bars to clear them. I doubt that you will be able to reach.

 

If you have fallen in and been drawn towards a moving propellor then will this device help? It will still chop off appendages that fit through the gaps, would hold a person underwater by the flow through the prop and if your clothing should pass through and stop the prop will make it extremely difficult to disentange you.

 

I also think the discipline that you are practising is a much better solution and covers more possibilities. If a child falls in, put the gearbox into neutral. Train a child to do the same if anyone else falls in.

 

What kind of stern does your boat have?

 

Richard

Putting the engine into neutral is already taught to all the crew, however I am not at all confident that in reality this would be done quickly enough.

 

Or boat has a trad stern (see pic)

[alan_fincher]

The vertical bar that I am refering to can be seen directly in the photo in front of the rudder and doesn't move.

That vertical bar is a pretty unique feature of your boat. I think.

 

I have never once seen anything like it on any other narrowboat, whether of working boat origin, or purpose built as a leisure boat.

 

No doubt someone will say builder "xyz" fits that to all their boats, but I have seen a lot of out of water narrowboats, and never one of those.

[robkg]

That vertical bar is a pretty unique feature of your boat. I think.

 

I have never once seen anything like it on any other narrowboat, whether of working boat origin, or purpose built as a leisure boat.

 

No doubt someone will say builder "xyz" fits that to all their boats, but I have seen a lot of out of water narrowboats, and never one of those.

Hi Alan,

That someone is me, and the builder is Roger Fuller, and as far as I am aware he fits them to all his boats. Certainly both shells I have had have had them fitted.

 

Rob

[Chris J W]

What about something like a chicken-wire cage? Something like an underwater version of the enclosures they put round office fans.

Edited August 12, 2009 by Chris J W

[nb Innisfree]

The vertical bar that I am refering to can be seen directly in the photo in front of the rudder and doesn't move.

 

Your idea sounds like it has merit but may be a pain when changing steerers or using both hands momentarily for some other purpose.

 

 

Putting the engine into neutral is already taught to all the crew, however I am not at all confident that in reality this would be done quickly enough.

 

Or boat has a trad stern (see pic)

 

Auto neutral when tiller is released would be effective if steerer fell backwards with no one else on deck, a bit awkward at times I agree but easily remedied by slipping box back into gear.

[RLWP]

What about something like a chicken-wire cage? Something like an underwater version of the enclosures they put round office fans.

 

Because instead of every scrap of stuff passing through the prop it will stick on the outside of the cage. All those jolly bits of leaf, weed and plastic bag will stop the water getting to the prop at all.

 

Rob, if you do decided to do this, then 2"x1" bar is way too much. 50mm x 6mm would be easier to bend, weld and install. Don't forget to leave enough space to get the prop off, check the stern bearing and black the hull.

 

And if you are really worried, why do something as dangerous as carry passengers on a traditional stern?

 

Richard

Edited August 13, 2009 by RLWP

[dave moore]

Hi Rob

For me - don't go there! I think I know what Roger (and Graham Edgson) would say.....

Best wishes

Dave

[blackrose]

I would expect them to have to be cleared of debris with monotonous regularity, and I would suggest that the risks created during such clearances would far exceed the risk that you are seeking to mitigate.

Hear him!

[robkg]

Hi Rob

For me - don't go there! I think I know what Roger (and Graham Edgson) would say.....

Best wishes

Dave

Hi Dave,

Don't worry, just hypothetical musings at this stage.

 

Rob

[DHutch]

I have thought about the 'getting drawn in to the propeller when in reverse' problem before and i have to admit when you read the article about the hire boater who suffered this awful fate it does focus the mind.

- However to me his incident was not due to lack of safety bars, but due to lack of forethought and training that led him to be standing in the way of the tiller, such that when it was drawn over due to hitting something in the water he was knocked over the rails at the back of the cruiser stern.

- I notice now all canaltime/hireacanalboat boats have a yellow line on the floor in an arc about the end of the tiller bar. Presumably at hand over they are told not to stand behind this, although many seam to non the less, perhaps because they have not been told WHY they should not. Of if they have, perhaps not in enough or graphic enough detail, like "if you do, and it goes wrong on you, you may well die a painful and nasty death' .

 

No, honestly, i know why your posting the post. And i think cages on outboard of sailing support boats is good. But on a narrowboat i just think it would be more hassle than its worth and that you line of discipline and explanation are far more appropriate. Presumable both children have being educated as to how to put the boat into neutral in am emergency?

 

I have although thought about what i would do if (heaven forbid) i were to fall over, and i think it would be a case of, scenario allowing, lie on your back and get your feet on the counter/rudderblade while keeping your head afloat with rapid arm movements! I'll endeavour report back if i can, should i have need to test this.

 

 

That said, if you do get a cage fitted, this is about the third thread we have had on the topic and it would be interesting to hear the outcome.

 

 

Daniel

[nb Innisfree]

I have thought about the 'getting drawn in to the propeller when in reverse' problem before and i have to admit when you read the article about the hire boater who suffered this awful fate it does focus the mind.

- However to me his incident was not due to lack of safety bars, but due to lack of forethought and training that led him to be standing in the way of the tiller, such that when it was drawn over due to hitting something in the water he was knocked over the rails at the back of the cruiser stern.

- I notice now all canaltime/hireacanalboat boats have a yellow line on the floor in an arc about the end of the tiller bar. Presumably at hand over they are told not to stand behind this, although many seam to non the less, perhaps because they have not been told WHY they should not. Of if they have, perhaps not in enough or graphic enough detail, like "if you do, and it goes wrong on you, you may well die a painful and nasty death' .

 

No, honestly, i know why your posting the post. And i think cages on outboard of sailing support boats is good. But on a narrowboat i just think it would be more hassle than its worth and that you line of discipline and explanation are far more appropriate. Presumable both children have being educated as to how to put the boat into neutral in am emergency?

 

I have although thought about what i would do if (heaven forbid) i were to fall over, and i think it would be a case of, scenario allowing, lie on your back and get your feet on the counter/rudderblade while keeping your head afloat with rapid arm movements! I'll endeavour report back if i can, should i have need to test this.

 

 

That said, if you do get a cage fitted, this is about the third thread we have had on the topic and it would be interesting to hear the outcome.

 

 

Daniel

 

Problem is if you are alone on rear deck, rear of boat hits something steerer overbalances or is knocked over by tiller, first thing they do is hold on to whatever is in their hand which unfortunately is usually the throttle lever which then goes into reverse complete with full throttle, forget about trying to keep back from prop, there is 30 + bhp of solid power driving it, no chance

[US Marines]

Hi Rob,

 

Like you, I actually like my kids so I'd like to think that they won't die horribly ripped to shreds and/or drowned when I could have done something more to have prevented it !

 

To this end, and like you, I think about teaching them to act safely and responsibly AS WELL AS thinking about whether there are additional practicable and cost effective safety features that may assist if things do go awry. For me, this is not an either/or situation.

 

If I (or my kids) were in the water at the back of a boat that was reversing would I want nothing between me/them and the mincing machine.....?

 

Errrr, no - in that situation, I wouldn't be counting the number of false rivets that make the hull look pretty, I'd be wanting something - anything - that might just help me/them stay alive.

 

One bar might be sufficient, or two, or three, as long as they were strong enough - Afterwards, I might even be grateful that it was only my flailing hand that had got the chop, instead of my chest - at least there might be an afterwards !

 

You definitely wouldn't need a chicken wire cage, which would weed up fast, and I don't think a couple of strong bars would slow you down noticeably, even if they hadn't been weeded for a few months...and yes, it would be sensible not to remove the weed whilst travelling down the canal I guess.....!

 

The bars would also be completely invisible when the boat was on the water, so the rivet counters et al wouldn't even know....

 

On a cost/hassle to risk mitigation ratio, this idea appears to have merit - to me at least - therefore, I say give them a go......!

Edited August 16, 2009 by US Marines

[Steve Priest]

I agree with Dhutch on this. I feel that any type of guard that is big enough or fine enough to be of use would cause a lot of problems with rubbish etc.

 

Most of the accidents that have envolved people being sucked into the propellor when the boat is in astern have not been due to falling off the counter, but being knocked off by the tiller. When the boat is in reverse the rudder is often sucked to one side or the other with considerable force, and anyone in the way can easily get knocked into the canal. It doesn't often happen when the engine is in ahead, but it can do, when hitting something in the water or when something substantial gets caught by the prop. The only safe place to stand whlst steering is in front of the tiller, wether the boat is in ahead or astern, all that will happen then is that the tiller is snatched from your hand.

 

I think that the most significant thing is that people understand the danger envolved, and use common sense

 

Although to some degree this is somewhat of a digression, the vertical post that has been referred to is a skeg bar, and is to some degree a throwback to wooden motor boats. It is used to stiffen a flat plate skeg and also to give a mounting for the bottom rudder cup. It was used almost universally until the steel and iron sided Grand Union boats were designed and built with a cast sternpost and skeg, allowing for a balanced self centring rudder. Some builders, Roger Fuller and Allens amongst them, still fit skeg bars

[ymu]

Safety for our nephews and niecelets was a primary concern for us when choosing a boat. We ended up with an unusual cruiser stern with walls all the way around the stern deck and side doors (which will be lockable once we get the steelwork done) so that noone can fall off the deck without trying really quite hard. With more open cruiser decks before that, I always had an adult stationed in the gap both sides before allowing the kids on deck. We had a semi-trad for a while, which felt blissfully safe with them on deck.

 

With a trad stern, I just wouldn't consider allowing anyone back there with me - it's just too dangerous, IMO.

[XAlan W]

Seeing photo

[XAlan W]

Seeing photo`s of some of the more modern built trad stern boats make me wonder if they are not making the problems that are being aired more likely to happen [god forbid] i refer to the up stand taffrail type bits on the counter anyone standing alongside the tiller bar when it gets whipped to one side for any reason stands no chance as the rail is between knee & waist height & the the tiller bar is chest height,perfect for folding you backwards over the stern. When I started my boating[on a full length working boat] I used to get a right rollocking if I stood any where other than in the hatches to steer + having the rear doors closed behind you was another + mark Some one said when I once asked[You have to have somewhere to sit]looked at me asthough I was from another planet whenIasked why he didn

 

Seeing photo`s of some of the more modern built trad stern boats make me wonder if they are not making the problems that are being aired more likely to happen [god forbid] i refer to the up stand taffrail type bits on the counter anyone standing alongside the tiller bar when it gets whipped to one side for any reason stands no chance as the rail is between knee & waist height & the the tiller bar is chest height,perfect for folding you backwards over the stern. When I started my boating[on a full length working boat] I used to get a right rollocking if I stood any where other than in the hatches to steer + having the rear doors closed behind you was another + mark Some one said when I once asked[You have to have somewhere to sit]looked at me asthough I was from another planet whenIasked why he didn

[Neil TNC]

Most of the accidents that have envolved people being sucked into the propellor when the boat is in astern have not been due to falling off the counter, but being knocked off by the tiller. When the boat is in reverse the rudder is often sucked to one side or the other with considerable force, and anyone in the way can easily get knocked into the canal. It doesn't often happen when the engine is in ahead, but it can do, when hitting something in the water or when something substantial gets caught by the prop. The only safe place to stand whlst steering is in front of the tiller, wether the boat is in ahead or astern, all that will happen then is that the tiller is snatched from your hand.

 

Advice from someone that knows.

Just look at the many modern trads and semi-trads where this is as good as impossible. There have been many pictures in the comics of reviewers steering beside the tiller.

[scrumpylurcher]

Just a thought when referring to putting the boaat in neutral. The Prop Does NOT stop turning just because the gearbox is in neutral, friction is enough to keep it turning at a rate that easily opened my shin up down to the bone. The only safe option is to stop the engine. Similarly I would never allow anyone to stand on the counter of my trad boat regardless of their experiance and the taff rails were the first thing I cut off my boat when I bought it.