How to balance the boat.

[rubblequeen]

Ok ( you can guess I'm noobie) Just had the last 10' of 50' re-plated. Do I now need to get rid of some ballast? Plus when getting the boat level(?) in the water should it be done with all tanks full or empty?

 

Thanks Tony

[Naughty Cal]

Trimming a boat is a bit of a black art. Still to master it on ours

[furnessvale]

Ok ( you can guess I'm noobie) Just had the last 10' of 50' re-plated. Do I now need to get rid of some ballast? Plus when getting the boat level(?) in the water should it be done with all tanks full or empty?

 

Thanks Tony

 

The choice of trim is very much a personal matter. Has the replating drawn the whole boat down in the water? If so, you may wish to remove a bit of ballast to bring it back where it came from. Then again, you may feel that the new, slightly lower, boat feels better.

 

Tanks full or empty. How do you intend running? Fill tanks to the brim and then run them until nearly dry or will you top up frequently? Any given tank in its full (or conversely empty) state may have a disproportionate effect on trim. Rather than trim with say 50% full tanks for an average, you may have to adjust trim with 25% or 75% in a tank.

 

Sorry I can't be more helpful.

 

George ex nb Alton retired

[nb Innisfree]

I would say fill any front tanks up and run rear tanks down, diesel or otherwise, and ensure boat isn't bow down but ideally slightly bow up.

[rubblequeen]

Thanks guys that has been most helpful. Knowing me i will probably keep all the tanks filled when travelling. So will go for 75% full up front and run the back down.

 

I've been told that the weed hatch base should be 2" under the water as a guide and then look to ensure the bow is up - is this correct?

[nb Innisfree]

Thanks guys that has been most helpful. Knowing me i will probably keep all the tanks filled when travelling. So will go for 75% full up front and run the back down.

 

I've been told that the weed hatch base should be 2" under the water as a guide and then look to ensure the bow is up - is this correct?

 

Sounds ok to me, our counter is about 3" under, depending on front water tank and I have been meaning to take out some ballast.

 

Remember, if you reduce front ballast stern will rise. and vice versa.

[bottle]

Thanks guys that has been most helpful. Knowing me i will probably keep all the tanks filled when travelling. So will go for 75% full up front and run the back down.

 

I've been told that the weed hatch base should be 2" under the water as a guide and then look to ensure the bow is up - is this correct?

 

I am guessing you mean the cavitation plate, the plate that is 'level' with the uxter plate, the flat plate that sits above the propeller, the 2" will vary with the boat, when moored a lot of boats have it just below the water surface but it goes lower as the boat 'sits' in the water under way.

 

Mine actually 'sits' two to three inches.

 

Bow up is the 'normal' attitude, again the amount will vary from boat to boat.

[NB Alnwick]

I prefer to have the counter plate, uxter plate or cavitation plate (call it what you will) about two inches out of the water when my fresh water tank (in the bow) is full or nearly full. Even so, when underway it will sit down in the water and by the time we have used about half of our fresh water, it is sitting in the water all of the time.

[sharpness]

Remember, if you reduce front ballast stern will rise. and vice versa.

 

Have you got that the wrong way round?

 

Steve

[nb Innisfree]

Have you got that the wrong way round?

 

Steve

 

Yeah, got my knicks in a twist

[PhilR]

Ok ( you can guess I'm noobie) Just had the last 10' of 50' re-plated. Do I now need to get rid of some ballast? Plus when getting the boat level(?) in the water should it be done with all tanks full or empty?

 

Thanks Tony

 

Tony

 

Sorry if I haven't read all the replies and might have missed something. Have you had re-plating or over-plating? If you have had over-plating done you will probably want to remove some ballast from the stern. If it is re-plating the weight and trim shouldn't be much different than previously.

 

I always reckon it is a good idea to have a few 28 lb and 56 lb weights on board to trim the boat to even up any listing to port or starboard. They are also handy as mud weights.

 

Phil

[Keeping Up]

Also think about how you actually want the boat to sit. Our first boat had a high bow which was also not very deep in the water. The boat got blown off course by the wind very easily, and pivoted around a point half-way back when steering. Our current boat sits almost level so it is much better in the wind, it steers by pivoting much nearer the front which I find much easier, and things don't roll back along the floor inside.

[rubblequeen]

This is so helpful for me thanks,

 

Remember, if you reduce front ballast stern will rise. and vice versa.

 

wish I had read a bit further down as spent ages trying to figure out why this should happen - was about to fill up the bath and make a model out of a washing up bottle actually might still do that sounds like fun on a rainy day. Oh why am I too old for a Blue Peter badge.

 

Back to reality,

Have you had re-plating or over-plating?

 

It has been over plated, the rear 10' so will I need to find out from the guys who did it how much it weighs and reduce the ballast at the back. Or doyou just look at it and judge?

 

 

the advise here has been really helpful for a complete novice.

 

Thanks Tony

[nb Innisfree]

This is so helpful for me thanks,

 

Remember, if you reduce front ballast stern will rise. and vice versa.

 

wish I had read a bit further down as spent ages trying to figure out why this should happen - was about to fill up the bath and make a model out of a washing up bottle actually might still do that sounds like fun on a rainy day. Oh why am I too old for a Blue Peter badge.

 

Back to reality,

Have you had re-plating or over-plating?

 

It has been over plated, the rear 10' so will I need to find out from the guys who did it how much it weighs and reduce the ballast at the back. Or doyou just look at it and judge?

 

 

the advise here has been really helpful for a complete novice.

 

Thanks Tony

 

Sorry I got the first bit the wrong way round, it should read 'reduce front ballast stern will sink and vice versa'

Reading from The Model Engineers Handbook steel is 0.285 lbs per cubic inch / 7.9 grams per cubic centimetre, so get the calculator warmed up!

[PhilR]

Back to reality,

Have you had re-plating or over-plating?

 

It has been over plated, the rear 10' so will I need to find out from the guys who did it how much it weighs and reduce the ballast at the back. Or doyou just look at it and judge?

 

Thanks Tony

 

Tony

 

Is the boat still out of the water? If so, I suggest you wait until it is re-floated. Most narrowboats have ¾ inch (18mm) plywood floors which are fixed down with no access to the ballast and bottom plate. It is very likely that the boat will sit too low at the stern after the over-plating. I suggest you cut out a section of floor at the rear of the cabin (approx 3 feet x 2 feet) . This should give you enough access to remove ballast as needed - and cut out more if that isn't enough. When you have finished you can fit a new section of removable floor. This also has the advantage of having access for a pump if you ever get a leak in the cabin bilge.

 

Trimming a boat is a bit of *suck and see* + a bit of personal preference/compromise. Personally, I would aim for the uxter plate to be 1 inch in the water with full tanks.

 

HTH

 

Phil

[Guest]

This photo (not a NB obviously)

 

 

Nicely shows how easily a boat can be affected by liquids on board.

 

Note the lean to starboard - it bugged us and got worse as the weeks hire went on.

 

When we took it back we got the explanation - diesel tank is port and toilet holding tank is starboard.

 

As our weeks hol went on the diesel tank emptied and the toilet filled - obvious when you know what it is.

[rubblequeen]

Tony

 

Is the boat still out of the water? If so, I suggest you wait until it is re-floated. Most narrowboats have ¾ inch (18mm) plywood floors which are fixed down with no access to the ballast and bottom plate. It is very likely that the boat will sit too low at the stern after the over-plating. I suggest you cut out a section of floor at the rear of the cabin (approx 3 feet x 2 feet) . This should give you enough access to remove ballast as needed - and cut out more if that isn't enough. When you have finished you can fit a new section of removable floor. This also has the advantage of having access for a pump if you ever get a leak in the cabin bilge.

 

Trimming a boat is a bit of *suck and see* + a bit of personal preference/compromise. Personally, I would aim for the uxter plate to be 1 inch in the water with full tanks.

 

HTH

 

Phil

 

 

It is very likely that the boat will sit too low at the stern after the over-plating. I suggest you cut out a section of floor at the rear of the cabin (approx 3 feet x 2 feet) . This should give you enough access to remove ballast as needed - and cut out more if that isn't enough. When you have finished you can fit a new section of removable floor.

 

Hi, no the boat is back in the water and unfortunately the flooring has been laminated. But have found a couple of bags of sand under one of the bunks at the rear so when all the work is finished and I can "play" I will see what happens when I remove these.

 

But even so sounds like a good idea to make some access into the bilge area.

 

Thanks Tony