How much weight is it safe to store on a narrowboat roof?

[Tony1]

 

Winter is coming, as so many people are fond of saying with a Winterfell accent (which it turns out is identical to the modern Sheffield accent).

 

Anyhoo, bags of coal will soon start appearing on the roofs of boats all over the place, and so the question has arisen (in my mind anyway) of how many bags it is safe to store up there. 

In a heated debate with another boater, I decided to plump for 10 x 25kg bags as my own estimated safe-ish limit, but this reckless fool was insistent that he would be fine with 25 bags on his roof, adding that he will not be cruising through any locks or busy locations this winter. 

The discussion was tragically cut short by a lack of beer, but I feel it may be taken up again before too long.  

But before I can tell him he is a blithering idiot (as he richly deserves) I need some scientific data from the experts here, ideally with clever sounding phrases like 'righting moment'- that sort of thing.

A few horror stories of boats capsizing because of weight on the roof would be the icing on the cake.

So over to our experts- how much coal is too much? 

 

[Mad Harold]

Load up the roof with what you think is enough, you and wife stand on the gunwale and give the boat a good rocking.

If it turns turtle, you've put too much stuff on the roof.  😜

[rusty69]

I can help you there, for I am that blithering idiot. I've had at least 20x25kg on our roof. I wouldn't recommend it though, the whole boat feels different. Given that ours is 70ft, the length and width may have some bearing on the matter (the boat, not the coal bags). 

[IanD]

Just now, rusty69 said:

I can help you there, for I am that blithering idiot. I've had at least 20x25kg on our roof. I wouldn't recommend it though, the whole boat feels different. Given that ours is 70ft, the length and width may have some bearing on the matter (the boat, not the coal bags). 

 

And the draft/weight -- a boat that's deeper in the water will also be heavier and have a lower centre of gravity (and a bigger metacentric height if you want to get technical) and have less of a problem with lots of coal on the roof... 😉

[Tony1]

Just now, rusty69 said:

I can help you there, for I am that blithering idiot. I've had at least 20x25kg on our roof. I wouldn't recommend it though, the whole boat feels different. Given that ours is 70ft, the length and width may have some bearing on the matter (the boat, not the coal bags). 

 

Joking aside though, for all I know 25 bags might be fine- but my winter cruising will involve a few locks (maybe more than a few), and the boat can get moved around quite strongly at times. 

Hopefully we'll get some well-informed info about it, but I do have an instinctive worry about putting more than 250-300kgs on the roof... 

 

 

[MtB]

12 minutes ago, Mad Harold said:

Load up the roof with what you think is enough, you and wife stand on the gunwale and give the boat a good rocking.

If it turns turtle, you've put too much stuff on the roof.  😜

 

My own suggestion is sort of related to the above.

 

My advice is to find the optimum number, keep adding bags to the roof until the boat capsizes, then take one off. 

[Tracy D'arth]

Get a camel and some straw.....

[IanD]

Just now, Tony1 said:

 

Joking aside though, for all I know 25 bags might be fine- but my winter cruising will involve a few locks (maybe more than a few), and the boat can get moved around quite strongly at times. 

Hopefully we'll get some well-informed info about it, but I do have an instinctive worry about putting more than 250-300kgs on the roof... 

 

 

It completely depends on the boat. The easy way to tell whether you're getting dodgy is to see how fast the boat naturally rocks from side to side with and without the coal on the roof; if it slows down a lot with the coal on, better remove some... 😉

 

(now you're going to ask what "a lot" is...)

[Tony1]

19 minutes ago, Mad Harold said:

Load up the roof with what you think is enough, you and wife stand on the gunwale and give the boat a good rocking.

If it turns turtle, you've put too much stuff on the roof.  😜

 

I like the plan, but I'm wondering if my wife might be persuaded to conduct the rocking tests whilst I stand on the bank recording the results with a clipboard.

One slight snag is that I don't currently have a wife, but given my immense charm and good looks, that should be solvable. 

How much does it cost to insure a wife these days? 

 

 

Edited September 12, 2023 by Tony1

[IanD]

1 minute ago, Tony1 said:

 

I like the plan, but I'm wondering if my wife might be persuaded to conduct the rocking tests whilst I stand on the bank recording with a clipboard.

One slight snag is that I don't currently have a wife, but given my immense charm and good looks, that should be solvable. 

How much does it cost to insure a wife these days? 

 

 

Insurance isn't the big problem, other running costs are *much* higher... 😉

Edited September 12, 2023 by IanD

[Laurie Booth]

33 minutes ago, Tony1 said:

 

Winter is coming, as so many people are fond of saying with a Winterfell accent (which it turns out is identical to the modern Sheffield accent).

 

Anyhoo, bags of coal will soon start appearing on the roofs of boats all over the place, and so the question has arisen (in my mind anyway) of how many bags it is safe to store up there. 

In a heated debate with another boater, I decided to plump for 10 x 25kg bags as my own estimated safe-ish limit, but this reckless fool was insistent that he would be fine with 25 bags on his roof, adding that he will not be cruising through any locks or busy locations this winter. 

The discussion was tragically cut short by a lack of beer, but I feel it may be taken up again before too long.  

But before I can tell him he is a blithering idiot (as he richly deserves) I need some scientific data from the experts here, ideally with clever sounding phrases like 'righting moment'- that sort of thing.

A few horror stories of boats capsizing because of weight on the roof would be the icing on the cake.

So over to our experts- how much coal is too much? 

 

As much as you can afford to be stolen

 

[Hudds Lad]

With a small mountain of coal on the roof you're going to spend more time meerkatting from side to side to see where you're going, which will increase the rocking as well. You could cruise the shallowest canals for winter, so any chance of capsizing is minimised as you'll hit bottom before reaching tipping point. Or invest in two more boats, strap one either side of your boat Hawaii 5-0 style to increase stability. This would have the added bonus of giving even more coal storage space and you'd be the toasty toast of the canals.

[Alan de Enfield]

1 minute ago, Hudds Lad said:

With a small mountain of coal on the roof you're going to spend more time meerkatting from side to side to see where you're going, which will increase the rocking as well. You could cruise the shallowest canals for winter, so any chance of capsizing is minimised as you'll hit bottom before reaching tipping point. Or invest in two more boats, strap one either side of your boat Hawaii 5-0 style to increase stability. This would have the added bonus of giving even more coal storage space and you'd be the toasty toast of the canals.

 

Any boat with less than two hulls is only half a boat !

 

 

 

 

[Tony1]

4 minutes ago, IanD said:

 

Insurance isn't the big problem, other running costs are *much* higher... 😉

 

I remember the days when a wife would run efficiently on as little as a litre of vodka per month, but I've heard that some of the modern models are far less efficient, requiring large quantities of much more exotic and expensive fuels. 

 

(PS- no offence is intended to any wives who happen to read this poor attempt at a joke)

[Puffling]

I'm wondering why a boater finds it necessary to store more than ten bags anyway. Are you not on the route of a fuel boat? Hedging your bets on steep price rises again?

[Tony1]

1 minute ago, Puffling said:

I'm wondering why a boater finds it necessary to store more than ten bags anyway. Are you not on the route of a fuel boat? Hedging your bets on steep price rises again?

 

I agree with this, which is why I keep 10 bags on the roof at most, and I find that a monthly fuel boat trip is usually enough to replenish in good time.

Although there is the risk of a bad winter and icing up for a week or two, so I try to keep another 3 or 4 bags in the cratch.

 

If I recall correctly, the benefit of the chap buying 25 or more bags in one go is that he gets a much cheaper price per bag, but he has to accept the lot in one delivery. Also, this chap will not be on the route of any fuel boats.

 

 

 

[Jen-in-Wellies]

53 minutes ago, Tony1 said:

bags of coal will soon start appearing on the roofs of boats all over the place, and so the question has arisen (in my mind anyway) of how many bags it is safe to store up there. 

Isn't that what your shower tray, or bath tub is for? Nice low centre of gravity.

The boat rolling over problem is nicely solved by some of the coal bags falling off the roof in to the cut, or on to the towpath before the boat flips.

[LadyG]

35 minutes ago, rusty69 said:

I can help you there, for I am that blithering idiot. I've had at least 20x25kg on our roof. I wouldn't recommend it though, the whole boat feels different. Given that ours is 70ft, the length and width may have some bearing on the matter (the boat, not the coal bags). 

If the whole boat feels different you have changed the C of G, bad idea.

[Tony1]

13 minutes ago, Jen-in-Wellies said:

Isn't that what your shower tray, or bath tub is for? Nice low centre of gravity.

The boat rolling over problem is nicely solved by some of the coal bags falling off the roof in to the cut, or on to the towpath before the boat flips.

 

Fill the shower with coal??

Pass me the smelling salts Mabel, for I fear I may faint with horror....

I'm not au fait with the showering habits of Morlocks, but the idea of the shower being out of action for 5 months is verging on savagery.

 

(Besides, its already full of baggage and spare bedding)

 

[Jen-in-Wellies]

1 minute ago, Tony1 said:

I'm not au fait with the showering habits of Morlocks, but the idea of the shower being out of action for 5 months is verging on savagery.

Ne're cast a clout till May be out. Showering will remove all that waterproofing and insulating goose grease.

[Machpoint005]

31 minutes ago, LadyG said:

If the whole boat feels different you have changed the C of G, bad idea.

 

And if the CG gets above the metacentre, very bad indeed..

 

[Mad Harold]

If you can afford one, would a Reflex diesel stove be better for long term fuel storage?

[Tony1]

16 minutes ago, Jen-in-Wellies said:

Showering will remove all that waterproofing and insulating goose grease.

 

What insulating goose grease?? 

I fear this may be straying into some sort of ungodly sexual practices.

This may not be the forum for this sort of thing ma'am. 

 

[IanD]

2 minutes ago, Tony1 said:

 

What insulating goose grease?? 

I fear this may be straying into some sort of ungodly sexual practices.

This may not be the forum for this sort of thing ma'am. 

 

 

The goose grease you put on underneath your undergarments in winter...

[tree monkey]

3 minutes ago, Tony1 said:

 

What insulating goose grease?? 

I fear this may be straying into some sort of ungodly sexual practices.

This may not be the forum for this sort of thing ma'am. 

 

That means either your invite to the goose grease gang has been lost in the post or more unfortunately you have been found lacking in moral fiber by the committee and you will never be able to enter the special restricted areas of the forum