Sunken Narrowboat

[KeithL]

I was at the docks this week and the boat (Angelwood) is being cleaned out:

 

 

I heard that there was no bulkhead - and when the engine bay started taking in water (possibly weed hatch?) then the boat started sinking fast.

Rob

 

Im interested to know how much water you need to have floating around inside a narror boat before it'll start going down ? i suppose it depends on how low any engine vents are positioned ?

[alan_fincher]

Im interested to know how much water you need to have floating around inside a narror boat before it'll start going down ? i suppose it depends on how low any engine vents are positioned ?

 

Not in the case where a weed hatch is not put back right, or even at all.

 

Once enough water has got in to bring the top of the weed hatch sides level with the cut, it can then be a bit like drawing a paddle, and the boat can go down within minutes.

 

Doesn't need any extra hull apertures to achieve this, unfortunately.

[David Mack]

Not in the case where a weed hatch is not put back right, or even at all.

 

Once enough water has got in to bring the top of the weed hatch sides level with the cut, it can then be a bit like drawing a paddle, and the boat can go down within minutes.

 

Doesn't need any extra hull apertures to achieve this, unfortunately.

The BSS used to require that weedhatch openings were at least 6 inches above water level, and other openings at least 10 inches.

 

On that basis a boat wouldn't actually sink until the stern had gone down by 6 inches, and even without a weedhatch cover fitted at all, that should buy you some time to realise there's a problem. As it is, some boats seem to have the weedhatch much lower, and you might not realise the boat was low in the water before the unstoppable inrush.

 

David

[magpie patrick]

The BSS used to require that weedhatch openings were at least 6 inches above water level, and other openings at least 10 inches.

 

On that basis a boat wouldn't actually sink until the stern had gone down by 6 inches, and even without a weedhatch cover fitted at all, that should buy you some time to realise there's a problem. As it is, some boats seem to have the weedhatch much lower, and you might not realise the boat was low in the water before the unstoppable inrush.

 

David

 

Well they did, but have you tried reaching a propeller where there is six inches of freeboard on the weedhatch? I have, because Ripple's does, and it's a pain.

 

The problem is that if the propeller turns with the weedhatch off the water needed to sink a boat enters very, very quickly

[Keeping Up]

I wonder what size of sealed engine compartment would be needed, before the boat would still float anyway (as the Titanic was supposed to do)

[magpie patrick]

I wonder what size of sealed engine compartment would be needed, before the boat would still float anyway (as the Titanic was supposed to do)

 

Well, by my reckoning Ripple probably couldn't sink with a simple leak into the engine compartment, but the propeller actually throwing the stuff in would be curtains.

 

On problem with many trads is that there is no bulkhead between the weedhatch and the cabin, and also no lifting plate on the counter. I have several times lifted the deckboards on Ripple to check things are alright, and if I suspected the back were getting low, I'd have the deck plate up in a second, on many trads, the first warning is when there is water in the cabin.

 

This isn't a problem with Trads per se, but it is possibly a design failing. If I filled Ripple's bilge to canal water level, I don't think she'd sink far enough for the exhaust to go under water (although the weedhatch would, if that were the cause of the problem)

[Keeping Up]

Good point about the prop throwing water into the compartment - that could of course make it fill up above the outside water level. Of course if there was a vent above the (stern-depressed) outside water level, it would exit the compartment and the boat might still stay afloat.

 

I've found that I can actually travel perfectly happily with my weedhatch removed, because the propeller is situated a few inches astern of the hatch. But of course if I go into reverse without the hatch in place, then I get a fountain - in fact the force of the water broke the bottom plate off my first weedhatch when I did an emergency stop (it made a heck of a clang in the propeller blades!)

[Doorman]

Good point about the prop throwing water into the compartment - that could of course make it fill up above the outside water level. Of course if there was a vent above the (stern-depressed) outside water level, it would exit the compartment and the boat might still stay afloat.

 

I've found that I can actually travel perfectly happily with my weedhatch removed, because the propeller is situated a few inches astern of the hatch. But of course if I go into reverse without the hatch in place, then I get a fountain - in fact the force of the water broke the bottom plate off my first weedhatch when I did an emergency stop (it made a heck of a clang in the propeller blades!)

 

Sounds like a course in Gynecology is required to clear your prop from any debris!

 

Did someone sack the welder after the bottom plate incident?

[Keeping Up]

Sounds like a course in Gynecology is required to clear your prop from any debris!

 

Did someone sack the welder after the bottom plate incident?

 

Luckily as it's a cruiser stern, access to the weedhatch is very good so it isn't too difficult. On the up-side, access is very good for clearing debris that has wound itself around the shaft in front of the prop

 

It was more the poor design than the quality of the welding which caused the bottom plate to break off. The boat-builder paid for a local company to redesign and replace it.

[Doorman]

Assuming that this sorry incident occurred due to the weed hatch either not being replaced, or, being replaced incorrectly, would it not be prudent for boat builders, to install a safety interlock switch that would be wired in series with the ignition key or starter button?

 

This simple but effective device would inhibit the the engine from being started, if the weed hatch is

not in place or fitted incorrectly. A warning light on the control panel would indicate why the engine has been 'locked-out'.

 

It would definitely be a cheaper option than a full re-fit!

[keble]

The boat is now floating - piccy taken yesterday at Glos docks.

Looks a bit damaged at the bow but probably repairable.

[canaldrifter]

 

I've found that I can actually travel perfectly happily with my weedhatch removed, because the propeller is situated a few inches astern of the hatch. But of course if I go into reverse without the hatch in place, then I get a fountain - in fact the force of the water broke the bottom plate off my first weedhatch when I did an emergency stop (it made a heck of a clang in the propeller blades!)

 

I think you mean 'with the weed hatch cover removed', but why would you want to even start the engine with the cover off?

 

Tone

[Heffalump]

Curiosity?

[canaldrifter]

.... killed the cat.

 

Tone

[Matthew Dowson]

Its too dangerous this boating lark, I'm going back to hang-gliding.

[Keeping Up]

I think you mean 'with the weed hatch cover removed', but why would you want to even start the engine with the cover off?

 

Tone

 

Yes OK, the cover (top plate with now-stronger down-brackets and a bottom plate) was removed.

 

I originally did it because I was trying to get a clue as to whether or not my prop-singing was affected by its proximity to the lower plate.

[canaldrifter]

Yes OK, the cover (top plate with now-stronger down-brackets and a bottom plate) was removed.

 

I originally did it because I was trying to get a clue as to whether or not my prop-singing was affected by its proximity to the lower plate.

 

Aah.... research purposes. Covers a multitude of sins.

 

Was it?

 

Tone

[Titan]

Perhaps a little premature as ive not as yet handed over the money, but i think as at present i am going to be the new owner of this boat, i will gratefully receive any fitting out advice any one has, initially it will be a deep clean and remove inner surface rust and painting of the inner, to make good, also the lifting and replacing of the perkins engine, may decide to rebuild?? depends on how far its, gone? so offers of engines also welcomed, this will be a long and trying project, but for some the only realistic chance of enjoying canal life kind regards Martin

[WotEver]

No advice, Martin, just warm wishes of good luck in this venture

 

It's good to know she'll live again.

 

Tony

[sebrof]

If you're right, Drifter, it makes rather a mockery of some people's obsession with hull thicknesses and overplating.

 

 

Well, you could say that because of that focus on sound hulls, no boats have sunk.

[WotEver]

Well, you could say that because of that focus on sound hulls, no boats have sunk.

12 months later, I doubt Athy even remembers posting that

 

T.

[sebrof]

12 months later, I doubt Athy even remembers posting that

 

T.

 

Tony, you do a very decent job of following me around and pointing out my errors, and generally cleaning up after me.

 

Rather like a dung beetle, in fact.

 

Keep at it.

[WotEver]

Tony, you do a very decent job of following me around and pointing out my errors...

Thank you for the compliment, but I'm a bit lost. What errors?

 

Tony

[Titan]

No advice, Martin, just warm wishes of good luck in this venture

 

It's good to know she'll live again.

 

Tony

 

Thankyou for your sentiments, i will try and do her justice, it goes without saying i do feel so sorry for the previous owners who lost so much when it sank, however im led to believe they had swiftly moved on to another newer boat and all is well and i wish them a trouble free life afloat, as for me lol, keep the faith??

[WotEver]

... as for me lol, keep the faith??

Absolutely! And ask away when you have any specific queries. In fact, I'd suggest you re-ask your question from a couple of posts back (deep clean etc) in a new thread in "Boat Building and Maintenance". It's likely to get a better response there.

 

As I said, good luck

 

Tony