'Adjustable' Ballast

[JJPHG]

As I'm laid up for a couple of months following a visit to the local human repair shop to put my shoulder back to how it should be I've returned to my NB planning.  Having read quite a few threads recently about dropping water levels I began to wonder if there is any benefit in having an adjustable ballast system to help with those times you might find yourself grounded.  I was wondering if there are any clever water storage systems/ideas out there whereby you could move water around between bow and stern positioned tanks (or even skin tanks if they exist) to help out.  As I will be solo I won't normally have any crew available to plonk down as temp ballast.  Also any views on the likely best hull design for the future if trends in water levels are maintained.  Surely the more modern bathtub designs are harder to shift with all the extra suction/friction force's grounding would generate.

 

As I would be solo I can sacrifice a bit of space.

 

PS Planning on about a 57'

[Captain Pegg]

18 minutes ago, JJPHG said:

As I'm laid up for a couple of months following a visit to the local human repair shop to put my shoulder back to how it should be I've returned to my NB planning.  Having read quite a few threads recently about dropping water levels I began to wonder if there is any benefit in having an adjustable ballast system to help with those times you might find yourself grounded.  I was wondering if there are any clever water storage systems/ideas out there whereby you could move water around between bow and stern positioned tanks (or even skin tanks if they exist) to help out.  As I will be solo I won't normally have any crew available to plonk down as temp ballast.  Also any views on the likely best hull design for the future if trends in water levels are maintained.  Surely the more modern bathtub designs are harder to shift with all the extra suction/friction force's grounding would generate.

 

As I would be solo I can sacrifice a bit of space.

 

PS Planning on about a 57'

Not having a crew onboard and not having ballast for the purpose of being able to move it will help you not to run aground in the first place. I feel this is a completely unnecessary consideration. The real world of boating is a lot simpler than reading this forum may make it seem. Do you think any of us would still be boating if it wasn’t? ?

 

JP

Edited July 21, 2019 by Captain Pegg

[MtB]

And low water levels tend to manifest themselves as lock closures to save water rather than you running aground. 

 

Unless you have a deep boat when dragging its arse along the bottom all the time is the usual effect. 

 

 

[zenataomm]

12 minutes ago, JJPHG said:

 Also any views on the likely best hull design for the future if trends in water levels are maintained.  

 

I reckon this future trend peaked around 1976 when the summit of the Leicester section doubled up as a short cut for commuters in Welford wanting to get to the M1.

You don't need transferable ballast, and many of us boat solo. 

There used to be a well known work boat captain in the 70s who went solo apart from his glaucoma, and he towed a butty!

Designing a boat to cope with shallow canals, can only mean making them more shallow, which of course is the reason they're getting silted up in the first place.

 

Get to learn how to handle your boat is the secret. 

[JJPHG]

11 minutes ago, Captain Pegg said:

Not having a crew onboard and not having ballast for the purpose of being able to move it will help you not to run aground in the first place. I feel this is a completely unnecessary consideration. The real world of boating is a lot simpler than reading this forum may make it seem. Do you think any of us would still be boating if it wasn’t? ?

 

JP

? - thanks but it's always nice to hear from those with far more experience/time on the water than I've had . 

 

Better to 'float' these ideas on here first and find out they are hair brained than wasting time thinking any more about it

[Tim Lewis]

We have a couple of tons of 56lb weights in Fulbourne which can be moved for extreme groundings, not that practical except for open hold working boats though!

[Yellowback]

There is a boat on the system that has inbuilt, pump filled and emptied boyancy tanks to raise and lower it in the water.I last saw it in the Northwich area about nine years ago.

[ditchcrawler]

1 hour ago, Yellowback said:

There is a boat on the system that has inbuilt, pump filled and emptied boyancy tanks to raise and lower it in the water.I last saw it in the Northwich area about nine years ago.

I think they were made at Wincham wharf with a covered rear deck/wheelhouse

[MtB]

1 hour ago, Yellowback said:

There is a boat on the system that has inbuilt, pump filled and emptied boyancy tanks to raise and lower it in the water.I last saw it in the Northwich area about nine years ago.

 

I believe Sea Otters all have this feature.

 

Or is it only the really short ones, so they can dump their ballast to get down to legal trailer weight?

 

 

 

[alan_fincher]

2 minutes ago, Mike the Boilerman said:

 

I believe Sea Otters all have this feature.

 

Or is it only the really short ones, so they can dump their ballast to get down to legal trailer weight?

 

 

 

 

I don't think Sea Otters have any optionality about having the ballast tank empty or full do they?

 

On the other hand the "Severner" boats built by Charles Hill for the Severn and Canl Carrying Company in the mid 1930s did I think incorporate a tank that could be filled or emptied.  Whether that tank is still in any of the surviving full length examples. I don't know, though.

 

[MtB]

2 minutes ago, alan_fincher said:

I don't think Sea Otters have any optionality about having the ballast tank empty or full do they?

 

Well ISTR reading on here a few years ago that they absolutely do, but I claim no expertise in Sea Otters. Never even been on board one. 

 

 

 

 

 

[roland elsdon]

We did just this for the first 4 years of owning our current boat2/1000 litre tanks in the bow. It allowed us to get into the llangollen and down the stratford by filling the tanks and dropping the bow.

however our hold was rendered useless for the front 12 feet.

in the end we did a huge weight redisribution hit on a compromise, and now rely on crt to helicopter a team in to rebuild locks and move copings should we need it.

[Sea Dog]

2 hours ago, Yellowback said:

There is a boat on the system that has inbuilt, pump filled and emptied boyancy tanks to raise and lower it in the water.I last saw it in the Northwich area about nine years ago.

Is it a black one that looks like a submarine? 

[Mike on the Wey]

24 minutes ago, Mike the Boilerman said:

 

Well ISTR reading on here a few years ago that they absolutely do, but I claim no expertise in Sea Otters. Never even been on board one. 

 

 

 

 

 

I have a Sea Otter, and the water ballast is controlled by gravity alone. Same on all narrow Otters, but I don't know about the (very small number of) sea-going boats that were produced.

[Neil2]

30 minutes ago, Mike the Boilerman said:

 

I believe Sea Otters all have this feature.

 

Or is it only the really short ones, so they can dump their ballast to get down to legal trailer weight?

 

 

 

Yes, they are all water ballasted, but once the ballast tank is full you can't adjust it - I guess it would make the boat dangerously unstable if you could, owing to the V shaped hull.

 

It was originally a feature to make the small boats trailable, but it makes a lot of sense on an aluminium boat.

 

My Otter has a midships water tank which is quite useful for increasing/decreasing the draft. 

[MtB]

1 minute ago, Neil2 said:

Yes, they are all water ballasted, but once the ballast tank is full you can't adjust it - I guess it would make the boat dangerously unstable if you could, owing to the V shaped hull.

 

It was originally a feature to make the small boats trailable, but it makes a lot of sense on an aluminium boat.

 

My Otter has a midships water tank which is quite useful for increasing/decreasing the draft. 

 

So how do you decrease the draft if you can't adjust the water ballast?

 

 

 

Or do you mean a domestic water tank?

 

[PaulJ]

1 hour ago, Mike the Boilerman said:

 

So how do you decrease the draft if you can't adjust the water 

 

I am pioneering a helium balloon system that can be deployed on the low pounds ?

[MtB]

7 minutes ago, PaulJ said:

I am pioneering a helium balloon system that can be deployed on the low pounds ?

 

I'd be tempted to just get a camper van....

 

 

[Jen-in-Wellies]

The couple of times I've run seriously aground on shallow section has been on river navigations rather than canals. Both times were single handing. At junctions with canal sections, the river can drop lots of silt out as it swirls in to the backwater leading to a lock. Produces a ridge of silt and vegetation that you run on to at speed. A similar thing can happen when a stream goes in to a canal. Narrowboats are usually ballasted bow up and have their potable water tanks at the bow. In both cases, pumping the water tank dry raised the bow further and helped me get off the silt bank. Only works if there is a reasonable amount of water on board to start with. Going through Standedge tunnel needed the water tank topped up to get in gauge. On my boat this gives 400kg of adjustable ballast built in! What is more, when removing it I have the water pump to do the work and somewhere to put the water. @JJPHG, you are over thinking things a bit. It won't be necessary to have specially removable ballast to single hand.

 

Jen

Edited July 22, 2019 by Jen-in-Wellies

[Neil2]

2 hours ago, Mike the Boilerman said:

 

So how do you decrease the draft if you can't adjust the water ballast?

 

 

 

Or do you mean a domestic water tank?

 

Sorry that wasn't very clear was it.  

 

Sea Otters have a ballast tank, basically the V section of the hull, which fills up with water through small holes when the boat is launched and drains when the boat is docked.  So there's obviously no way to empty this and if you could it would seriously affect the stability of the boat.  

 

The displacement of Sea Otter boats is still quite a bit less than an equivalent steel narrowboat though, so depending on the capacity of the fresh water tank the amount of domestic water on board can make a big difference to the draft.  On most boats with a conventional bow tank it affects the trim, but on my boat the tank is almost exactly midships and the boat trims dead level, so emptying and filling the tank alters the overall draft.  I reckon the difference between full and empty is as much as 2-2 1/2" which is significant on some canals. 

   

[cuthound]

On 22/07/2019 at 11:14, Mike the Boilerman said:

 

I'd be tempted to just get a camper van....

 

 

 

Wouldnt that just sink? ???

[mrsmelly]

On 22/07/2019 at 00:10, Mike the Boilerman said:

And low water levels tend to manifest themselves as lock closures to save water rather than you running aground. 

 

Unless you have a deep boat when dragging its arse along the bottom all the time is the usual effect. 

 

 

I agree. I havnt been aground for many years. Ive scraped the bottom on shallow corners but I dont even carry a pole anymore, havnt used one for twenty years. If levels in specific pounds I remain tied up till its risen. I also never buy deeper draughted boats as I learnt my lesson with the Udson.

[Iain_S]

On 22/07/2019 at 09:07, alan_fincher said:

 

I don't think Sea Otters have any optionality about having the ballast tank empty or full do they?

 

(snip)

They don't. Could be added, I suppose. Would need an air pump and a means of sealing up the ballast tank vent,

Would be an extremely bad idea. The ballast tank is full when the boat is in the water. A partially filled tank would suffer from surface effect, rendering the boat very unstable with the tank partially full.

[WotEver]

15 hours ago, Iain_S said:

Would need an air pump and a means of sealing up the ballast tank vent,

Need to find a decommissioned submarine I guess...

[carlt]

On 22/07/2019 at 11:05, PaulJ said:

I am pioneering a helium balloon system that can be deployed on the low pounds ?

 

I have fitted Ecofans along the metal roof which is heated with bunsen burners hanging from the ceiling in the cabin.

 

This system provides enough lift to cope with shallow waters and, when the burners are turned up full. the boat can bypass lock flights altogether.

 

I am adapting the system to allow wide beam boats to navigate narrow canals.