Jump to content

gravel for ballast?

Lottiespal
 Share

Featured Posts

bowten Rising Star

bowten

Posted
Posted

Ian,

 

That's fine - - - you use little stones wherever you may wish

 

I shall continue with my options of sheet steel, cut rail sections or cast iron

 

I am also pleased to have a pump, in the bilge, in the main shell, (in addition to the bilge pump in the stern.)

Dont yer get alot of rattling when yer old engine is tickin over.

Link to comment
Share on other sites
Barry Veteran

Barry

Posted
Posted

 

Apart from it getting wet & the problems then drying it out, why would you want ballast full of "air spaces between each pebble". The volume of ballast you need would be considerably greater to achieve the same weight. Ballast should have as great a density as possible, especially in the shallow space available in a narrow boat to allow the maximum airspace to allow circulation of air to help keep it dry.

 

Steve

 

The smaller the gravel the smaller the air spaces between them

 

Isn't pea gravel as dense, volume for volume, as other forms of gravel?

Link to comment
Share on other sites
Proper Job Veteran

Proper Job

Posted
Posted

Ian,

 

That's fine - - - you use little stones wherever you may wish

 

I shall continue with my options of sheet steel, cut rail sections or cast iron

 

I am also pleased to have a pump, in the bilge, in the main shell, (in addition to the bilge pump in the stern.)

Mind your pump doesn't suck in one of those rail sections in. It will make the ingestion of a bit a pea gravel look positively beneficial

Link to comment
Share on other sites
ChrisPy Veteran

ChrisPy

Posted
Posted

The smaller the gravel the smaller the air spaces between them

 

Isn't pea gravel as dense, volume for volume, as other forms of gravel?

yes and yes. the proportion of air space is a factor of the shape of the stones only, not their size.

there is logic in using BIG stones (say 20mm or even 40mm, single size), and it doesn't need to be pea shaped. Natural river bed gravel is much better (harder, better shaped) than the normally available crushed stone that is used in concrete.

Link to comment
Share on other sites
sharpness Rising Star

sharpnessDonate to Canal World

Posted
Posted

There is no sand in pea gravel sir a little dust perhaps.Pea stones are well rounded LITTLE STONES with little or no dust present and no active corrosion properties to damage steel.9 tons of ballast in a 10ft x 55ft shell spreads well and leaves plenty of space to add underfloor insulation.A boat I built several years ago had serious leak when the water tank breather became detached and every time the owner Paul filled his stainless steel water tank he also filled his boat.Some water fillings later the depth was such that he noticed the water had risen and reached the floor covering at the stern.We pumped out the water with no detriment to the drill pump and the LITTLE STONES and underfloor dried naturally within a few weeks.I went back to see his boat a few weeks later and placed my hand within the LITTLE STONES and lo and behold it was dry and even warming to my skin.A bilge pump is used in a engine room and that,in modern boats,is separate from the main shell where ballast is lain.The whole idea is to have air pockets so that air can circulate.I came to this conclusion several boats ago after seeing the effects of concrete or cement slabs on steel.You have of course seen the results of steel reinforcement bars running through concrete structures i.e.road bridges.However please carry on with your own preference.Long live the LITTLE STONES and get rid of the big stones.Regards Ian.

 

Interesting story Ian but I remain unconvinced that loose gravel has any merit over the usual ballast choices, only the opposite.

I'll stick to mine, you stick to yours.

 

Steve

Link to comment
Share on other sites
RLWP Veteran II

RLWP

Posted
Posted

The smaller the gravel the smaller the air spaces between them

 

Isn't pea gravel as dense, volume for volume, as other forms of gravel?

 

Ahem...

 

If you assume that the granules are approximately spherical, then the interstitial volume (the gaps between the grains) never changes as the ball size changes. Bigger balls, bigger gaps, smaller balls, smaller gaps

 

I used to have a big sum that explained that properly

 

Richard

Link to comment
Share on other sites
sharpness Rising Star

sharpnessDonate to Canal World

Posted
Posted

, then the interstitial volume (the gaps between the grains) never changes as the ball size changes.

Richard

 

Do you mean that?

Dont you mean the ratio between the size of the grain & the size of the gap doesnt change.

Bigger balls, bigger gaps, smaller balls, smaller gaps would seem to mean that.

 

Steve

Link to comment
Share on other sites
alegood Explorer

alegood

Posted
Posted

When refitting my narrowboat I jack-hammered out the paving slabs (they were such a tight fit that there was no other way of doing so), de rusted and then bitumined the base plate. I worked out the mass that I had removed and then re-ballasted with two and a half tonnes of tractor weights (the removable weights on the front of the tractor, used to balance out the plough). They weigh between forty and sixty five kilo's each. They fitted very nicely between the bearers which were two foot apart, and it meant I could lay the floor directly on top of the bearers. Because the weights are irregular shapes there is plenty of air space around them. I also made sure that there was some insulating material betwwen the base plate and the ballast as I didn't want any galvanic action to happen. I was very lucky in that I scrounged most of them off of friends and I think I only had to spend about £100. I dread to think how much they are worth in scrap value!!!.

Link to comment
Share on other sites
bowten Rising Star

bowten

Posted
Posted

No - - but it may mean that people that use it for unsuitable functions may be more dense than others

 

(all boaters excepted of course!)

 

<_<

No feckin wonder there has been some well known names in the boating fraternity left this site,L.O.L.I will get mi calculator out and determine the ratio of little stones to big stones and their effect on air swirl in and around the bilge.Hopefully any of you who have used cast iron,pig iron or any other metal have suitably smothered it in an anti rust formulation .Having said that you could probably sell yer ballast to the Chinese for more than yer boats worth.My regards to yer and all the top boat fitters on this site.Next time any of yer are in Skipton ask fer the Boatman and have a look at a proper boat.Oh and for Gods sake sort yer battery calculations out and I mean real world calculations,oh no yer can't can yer he's left the site.Ian the Boatman.

Link to comment
Share on other sites
RLWP Veteran II

RLWP

Posted
Posted

Do you mean that?

Dont you mean the ratio between the size of the grain & the size of the gap doesnt change.

Bigger balls, bigger gaps, smaller balls, smaller gaps would seem to mean that.

 

Steve

 

The ratio doesn't change is what I meant, although I seem to have explained it in a clumsy way. There is just as much air in a bag of big stones as there is in a bag of little stones.

 

Richard

Link to comment
Share on other sites
Grace and Favour Veteran II

Grace and Favour

Posted
Posted

No feckin wonder there has been some well known names in the boating fraternity left this site,L.O.L.I will get mi calculator out and determine the ratio of little stones to big stones and their effect on air swirl in and around the bilge.Hopefully any of you who have used cast iron,pig iron or any other metal have suitably smothered it in an anti rust formulation .Having said that you could probably sell yer ballast to the Chinese for more than yer boats worth.My regards to yer and all the top boat fitters on this site.Next time any of yer are in Skipton ask fer the Boatman and have a look at a proper boat.Oh and for Gods sake sort yer battery calculations out and I mean real world calculations,oh no yer can't can yer he's left the site.Ian the Boatman.

 

I suspect that you feel slighted.

 

That's only a suspicion though - and I do hope I'm wrong.

 

Addressing your questions, though - -

 

You'll be delighted to learn that all my ballast was suitably treated against rust (it's good of you to ask), and I've done a quick calculation - and unfortunately the value of my ballast - even to the ever-mineral acquisitive Chinese - is not sufficient for me to sell it to them, and replace it with any other type of ballast

 

I'll happily pop-in to see you when I'm next in Skipton (for I will be) and look forward to a tour round a proper boat.

 

You'll also be relieved to learn that my battery calculations are spot-on thanks - - but, should I need advice or need someone to double-check my calculations - I won't hesitate to ask.

 

Regards

Link to comment
Share on other sites
sharpness Rising Star

sharpnessDonate to Canal World

Posted
Posted (edited)

No feckin wonder there has been some well known names in the boating fraternity left this site,L.O.L.I will get mi calculator out and determine the ratio of little stones to big stones and their effect on air swirl in and around the bilge.Hopefully any of you who have used cast iron,pig iron or any other metal have suitably smothered it in an anti rust formulation .Having said that you could probably sell yer ballast to the Chinese for more than yer boats worth.My regards to yer and all the top boat fitters on this site.Next time any of yer are in Skipton ask fer the Boatman and have a look at a proper boat.Oh and for Gods sake sort yer battery calculations out and I mean real world calculations,oh no yer can't can yer he's left the site.Ian the Boatman.

 

How sad.

I was going to ask about the calculations that gave 9 tons of gravel in a 10ft x 55ft boat (post 25). If the cabin space available for ballasting is say 45 ft long that gives 40 square metres. At 1.5 tonnes/m3 that gives 6 m3 of gravel. Spread over 40 sq metres my mental maths says the gravel will be about 150mm or 6" deep. Just like being on the beach. :rolleyes:

 

Steve

Edited by sharpness
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.