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Diverting roof drainage channels


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Hi.   Mrs Ando suggested I run this by some people before drilling holes in my roof!

We have a standard NB with Liverpool style hull, 57' cruiser stern and pram cover.   The canopy is lovely BUT, the roof gutters were designed to channel rain off the roof and dump it over the rear bulkhead onto the cruiser stern where it would either flood over the sides or be taken away by the (regularly maintained and cleared) scuppers.   

Trouble is, with the pram cover up and heavy rains like we've had recently, the rainwater literally pours from the roof gutters and splashes on the rear deck inside the pram cover.   Approx 1 gallon/min the other day and looked like a leaking lock gate!

So I thought I'd cut a small rectangular section out the the roof gutter about 12" before the gutter's end and araldite some channel in the gap that would divert the rain water over the side before it reaches the end of the existing gutter - i.e diverting the flow over the side instead of over the end.   Alternatives would be to drill round holes and insert suitably shaped piece of pipe.  all inserts would be shaped to extend within the flow area to be sure of catching all water before the bulkhead.

Can anyone see any issues, faults or future maintenance issues with this plan, please?

Much appreciated in advance

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If you're talking about the integral box section type handrails, you'll find that they're actually hollow and by removing a section for drainage you're causing further problems.

 

I have seen a sort of scupper welded to the cabin top before now to divert some of the water over the stern most (and lower) drainage channel. I've tried to find a picture online, but can't at the mo. Its basically maybe half inch bar welded as to divert the water running back.

 

 

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Get more ballast in the bow so the water runs forward.😎 

If you must put a drain through the handrail it will need to be welded in position.

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I have a Liverpool Boat and it has cutouts about 150mm long in the handrail placed before the cabin end. These work perfectly at diverting water over the side in all conditions Because of the dynamics of the water flow in heavy rain I suggest this is the length you need if the water is not to simply rush past  - drain holes will only work on light rain conditions.

 

Because of the way the handrail is made I'm with Loddon in thinking that if you do this change then all the exposed edges need fully welding to ensure you have no leaks into the boat - relying on Araldite (or any sealant) is likely to be unsuccessful and a long term nightmare.

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This works well on our boat but it was added at the build stage, the ends of the handrail are welded closed and the diverter is welded to the roof.

 

 

handrail drains.jpg

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Had similar on my last narrowboat.My simple fix was to use Stixall to make  a couple of "diverters".Squeeze it onto the roof and leave a rounded bead,or if you feel artistic,you can shape it to an elongated square.

 

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27 minutes ago, PeterF said:

This works well on our boat but it was added at the build stage, the ends of the handrail are welded closed and the diverter is welded to the roof.

 

 

handrail drains.jpg

 

2 minutes ago, Idle Days said:

A similar solution on our boat which works well.

 

IMG_1601.jpeg.1b379cd3d0d7afd40007b11303156f13.jpeg

 

Similar arrangement on our Colecraft cruiser stern. It works very we'll, but the cruiser deck drainage also works properly.

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1 minute ago, Machpoint005 said:

 

 

Similar arrangement on our Colecraft cruiser stern. It works very we'll, but the cruiser deck drainage also works properly.

 

That's possible because our's is a Colecraft Cruiser stern. 😁 

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We had a very slight list to port which resulted in any water running off the roof / cabin sides running down onto the gunnel. Because of the list the water would run down in the 'corner' formed by the gunnel and the cabin side, running towards the stern and would run onto the cruiser stern.

 

I ended up putting a 'snail-trail' of silicone on the gunnel, at an angle, deflecting the run-off from the end of the cabin overboard. Simple, and effective.

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13 minutes ago, Alan de Enfield said:

We had a very slight list to port which resulted in any water running off the roof / cabin sides running down onto the gunnel. Because of the list the water would run down in the 'corner' formed by the gunnel and the cabin side, running towards the stern and would run onto the cruiser stern.

 

I ended up putting a 'snail-trail' of silicone on the gunnel, at an angle, deflecting the run-off from the end of the cabin overboard. Simple, and effective.

Sally has made it clear she claims no responsibility for diverting people's rainwater whatever compound was squeezed over her...

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Unless they are good at welding I wouldn't suggest the OP starts cutting/drilling anything themselves. Araldite, filler, sikaflex, epoxy, gunk, whatever will not be up to this job and when they fail the box section handrails will rot from the inside. It will always look and degrade like a 'bodge' job, okay for something trivial in the shed but not great on a valuable asset like a reasonably modern narrowboat. The solutions in the photos posted by owners look to be what OP is wanting to achieve and well integrated at build stage. For this kind of finish as a retrofit, finding a good welder for a bit should be the first port of call.  The cutting, forming, welding and finishing shouldn't be a massive task for a skilled professional with the right tools, leaving the owner with the prep work and painting bits of the job. 

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29 minutes ago, Tracy D'arth said:

Sell it and buy a decent trad boat hull with the correct upsweep on the cabin rear and you will never have this problem again. Boats were built with shape in the hull and cabin for very good reason.

An excellent, if somewhat expensive, solution! Alternatively, junk the fugly pram hood, improve the aesthetics of the boat and let the drainage work as designed?

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Thanks for all your thoughts and advice so far.   I'l look for a welder.   Is it possible to weld onto the roof without having to strip the wooden ceiling and insulation inside?

 

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2 hours ago, PeterF said:

This works well on our boat but it was added at the build stage, the ends of the handrail are welded closed and the diverter is welded to the roof.

 

 

handrail drains.jpg

I may be being thick here, but from the picture, can't see where the water goes.   The diverter looks as if it acts only as a dam.  Can someone explain, please?

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1 minute ago, Cal Ando said:

I may be being thick here, but from the picture, can't see where the water goes.   The diverter looks as if it acts only as a dam.  Can someone explain, please?

Through the gap in the handrail and overboard.

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1 hour ago, Cal Ando said:

I may be being thick here, but from the picture, can't see where the water goes.   The diverter looks as if it acts only as a dam.  Can someone explain, please?

Have a look at the second picture, mine is the same as this apart from the flat top of the handrail continues over the gap, so mine is more of a hole rather than a gap. This means that there is less risk of losing finger grip if not paying attention.

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7 hours ago, Tracy D'arth said:

Sell it and buy a decent trad boat hull with the correct upsweep on the cabin rear and you will never have this problem again. Boats were built with shape in the hull and cabin for very good reason.

 

And there you have a problem in itself. Our first boat was a Jonathan Wilson shell with just such an arrangement, and water puddled on the roof because the "correct" location of the gaps in the handrail either side varied according to the boat's attitude (how full the water and diesel tanks were). That meant the roof had to be partially rubbed down and repainted, over and over again.

 

When we were looking for our present boat we found a very strong candidate, but it was another Wilson (much newer) and had exactly the same problem. That was one of the many reasons we ended up with a Colecraft, and I note that other posters also saw the virtue of good design!

 

 

6 hours ago, Cal Ando said:

Thanks for all your thoughts and advice so far.   I'l look for a welder.   Is it possible to weld onto the roof without having to strip the wooden ceiling and insulation inside?

 

 

Yes, it should be, because we're not talking full penetration welds, but it's a great advantage if you have rock fibre insulation rather than plastic foam ... you know, the stuff that isn't supposed to burn.

I recommend a fire-watcher inside the boat.

 

Or new batteries in the smoke alarm.

Edited by Machpoint005
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52 minutes ago, Machpoint005 said:

 

And there you have a problem in itself. Our first boat was a David Piper shell with just such an arrangement, and water puddled on the roof because the "correct" location of the gaps in the handrail either side varied according to the boat's attitude (how full the water and diesel tanks were). That meant the roof had to be partially rubbed down and repainted, over and over again.

 

When we were looking for our present boat we found a very strong candidate, but it was another Piper (much newer) and had exactly the same problem. That was one of the many reasons we ended up with a Colecraft, and I note that other posters also saw the virtue of good design!

 

 

 

Yes, it should be, because we're not talking full penetration welds, but it's a great advantage if you have rock fibre insulation rather than plastic foam ... you know, the stuff that isn't supposed to burn.

I recommend a fire-watcher inside the boat.

There is not the full required upsweep on the early Piper shells that David built.  A proper shell has sufficient to make the rear drain work properly. Look at a Gorton, Tyler or Heywood shell, they never have puddles anywhere on the roof.

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7 minutes ago, Tracy D'arth said:

There is not the full required upsweep on the early Piper shells that David built.  A proper shell has sufficient to make the rear drain work properly. Look at a Gorton, Tyler or Heywood shell, they never have puddles anywhere on the roof.

 

Nether does our Colecraft. 

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9 minutes ago, Tracy D'arth said:

Look at a Gorton, Tyler or Heywood shell, they never have puddles anywhere on the roof.

Beg to differ;

Idleness built by Heywood always had puddles next to the handrail on its roof, requiring constant attention for the nine years I owned it.

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Just now, Loddon said:

Beg to differ;

Idleness built by Heywood always had puddles next to the handrail on its roof, requiring constant attention for the nine years I owned it.

Well if anyone had to have one puddle it would have to be you!  All I can say is that I have not seen one do this. Perhaps the boat name encouraged puddles to lie idle on the roof instead of running off?

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