Qquestion regarding ballast

[trebby91]

Hi, All.

We purchased a sail away narrow boat it is now fitted out and in the water.

We intend to live aboard consequently it has loads of “stuff” aboard, to get the boat about level I have had to remove about 12 concrete blocks from the ballast at the back end.

Will this have any detrimental effect on a river?

[Arthur Brown]

That really depends on how the designer intended the boat to sit in the water. At worst case you propeller will come too close to the surface and may spray water or cavitate losing you power. However you may have loaded the boat to where the designer intended. Probably it would be good to ask them.

[Ryeland]

Are your diesel and water tanks full?

 

Richard

[XAlan W]

Hi, All.

We purchased a sail away narrow boat it is now fitted out and in the water.

We intend to live aboard consequently it has loads of “stuff” aboard, to get the boat about level I have had to remove about 12 concrete blocks from the ballast at the back end.

Will this have any detrimental effect on a river?

 

If the way you have it ballasted means the bottom of the counter sits at the water level or just under with the boat stationary, you should have no problems as the boat will pull down when under way, only with the counter out of the water when moving are you likely to get cavitation

[system 4-50]

Hi, All.

We purchased a sail away narrow boat it is now fitted out and in the water.

We intend to live aboard consequently it has loads of "stuff" aboard, to get the boat about level I have had to remove about 12 concrete blocks from the ballast at the back end.

Will this have any detrimental effect on a river?

Depends on how deep the river is where you have put the blocks.

{Coat}

[bottle]

Trebby

 

I can beat your 12, I removed 14 but I had replaced my batteries with some much heavier ones.

 

The boat always sat to deep in the water anyway, I know mine is about right now by the bands around the stern, the uxter plate is still about 3" under water when moored.

[Dorman]

Hi, All.

We purchased a sail away narrow boat it is now fitted out and in the water.

We intend to live aboard consequently it has loads of “stuff” aboard, to get the boat about level I have had to remove about 12 concrete blocks from the ballast at the back end.

Will this have any detrimental effect on a river?

 

I removed steel and concrete because of dragging the bottom and putting in tool boxes and batteries etc. I first filled the water tank at the front and made sure there was still about 1-1 1/2 inch above the counter just below the bottom red painted band rubbing band to stop cavitation and the boat handles great--much better to swing out the back when steering. The swim is long on our boat however. Occasionally on the river if someone passes at speed it might slurp but the engine doesnt rev up.

The prop to counter is about 3" so probably about 4" min below the water line.

 

Simon

[blackrose]

Hi, All.

We purchased a sail away narrow boat it is now fitted out and in the water.

We intend to live aboard consequently it has loads of “stuff” aboard, to get the boat about level I have had to remove about 12 concrete blocks from the ballast at the back end.

Will this have any detrimental effect on a river?

 

Could you clarify please? Your statement in bold is rather ambiguous. Do you mean you've taken ballast out to compensate for all the stuff you've put into the boat?

 

Firstly, are you sure that the weight of what you've taken out is roughly the same as what you put in? Secondly, the ballast you took out sat very low in the hull providing the boat with a low centre of gravity/metacentric height. The ballst was also restricted in its movements by the floorboards above. Can you say the same about the stuff you put in? I think what you've actually done is to raise the CoG and the metacentric height of your boat.

 

Personally I wouldn't have taken any ballst out until I had seen what was going on. I'd have put a few small marker pen lines just above the waterline around the back of the boat (or just measured the height of a rubbing strake in relation to the waterline), then I'd have loaded the boat with all the stuff and checked to see how it had affected the boat. Then, if necessary I'd have taken some ballast out.

Edited February 8, 2012 by blackrose

[trebby91]

I have removed the 4 leisure batteries and replaced them with 6 X 2 volt traction batteries giving 525 AH.

There is also a portable inverter generator on the back end sitting at floor height all the other weight is fixed, wardrobe, bed and copboards.

It is still sitting a little low at the back, the bottom of the boat at the back is about 4 inches below the surface, the fuel tank will take about another 60 litres.

The front end at the highest point (roof) stands 67 inches above the water line with the water tank full but I only have about 2 inches clearance for the gas locker drains above the water.

I still have ballast under the floor at about 7 feet from the back bulk head.

 

Dare I remove more?

Regards,Brian.

[Tony Brooks]

I have removed the 4 leisure batteries and replaced them with 6 X 2 volt traction batteries giving 525 AH.

There is also a portable inverter generator on the back end sitting at floor height all the other weight is fixed, wardrobe, bed and copboards.

It is still sitting a little low at the back, the bottom of the boat at the back is about 4 inches below the surface, the fuel tank will take about another 60 litres.

The front end at the highest point (roof) stands 67 inches above the water line with the water tank full but I only have about 2 inches clearance for the gas locker drains above the water.

I still have ballast under the floor at about 7 feet from the back bulk head.

 

Dare I remove more?

Regards,Brian.

 

 

I do not understand why you feel that you want to. I suppose the RCD calculations might be put out by an increased draft but unless you intend to boat in exceptionally shallow waters the draft on a TYPICAL modern boat will have little real effect. However as said raising the C of G will. However even then on a flat bottomed boat I doubt you would notice the increase in roll on any inland waterway.

 

Many gas lockers have two sets of "drains". low ones that allow water to flood in and then the actual drain above the waterline. The BSS book illustrates this. You do need to watch the height of things like drain openings above the waterline (the BSS book gives minimum height) but even then using metal pipe inside the boat can easily take care of this. That only leaves the height of self draining cockpit vents (if fitted) and external engine breather ports.

 

Too little draft will allow the prop to ventilate but I can not see a problem with too much except for the vent issue.

 

 

 

Altering the fore-aft trim will alter the point around which the boat pivots but as it seems to be a new boat you will get used to the pivot point wherver it ends up.

[keble]

 

 

Dare I remove more?

Regards,Brian.

One thing to be careful of (mentioned by blackrose) is if you inadvertently make your centre of gravity too high.

Then you are in danger of tilting if everyone on board is on the same side. I had that on my boat when it was new;it's alarming and potentially dangerous!

[Hattie]

Sorry to tag on to the end of an old thread, but I thought it made more sense than starting a whole new one! An additional question about ballast - any help most appreciated.

When we had our boat surveyed, the surveyor mentioned that she sat quiote low in the water and it would be a good idea to remove some ballast from the engine room. However, the previous owner said he had only added the extra ballast because she lists slightly. However, having cruised about for the weekend, she is still listing but is also low in the water - would it be foolish to remove some ballast on the side she is listing, or would this fix two problems at once (provided I wasn't too gung ho about taking out the ballast)...

 

Thanks in advance

 

H

[john6767]

If you have access to get the ballast out, you can do any harm, take some out and see what the effect is, you cna always put it back. Don't forget the state of the water and diesel tanks will probably have a significant impact on how the boat sits.

[ditchcrawler]

Do you have a pump out toilet tank on one side?

[Hattie]

We do indeed - I thought this may be why she was listing but have just had a pump out and although it had made a little bit of difference, there is still a definite tilt to one side. I may try taking some out then if it can't do any harm (just didn't want to unbalance it - had visions of the boat rolling over in the canal)...

[Kae]

Take a bit out and see how the list changes. You won't do any harm by doing this and if you do it methodically you can always put it back again.

The only damage you're likely to do is to your back!

 

I'd always take heed of Tony's advice first and foremost.

Edited September 10, 2013 by Kae

[bottle]

Before you take it out, move it from the low side to the high side, you will have to move half as much as removing it.

 

See how she sits if still to deep then remove equally from both sides.