Lead shot inside doubled truck tire inner tubes cut into 14" pieces, then cable tie the ends. Each one ends up weighing 40# or so, and they can be nestled into odd shaped spaces.
It wasn't my idea, but is sure works great. We used robust cable ties, one put on first to close the ends, then doubled the tail over and attached a second one to reduce the length and double seal it. What is nice is that they conform to pretty much whatever shape you have to work with. I stuffed around 1,000# under the generator stand, feeding them through the small opening available.And, if new lead shot is too spendy, you can go to your local scrap metal yard and buy lead pigs, or you can scrounge the lead from plumbers, tire shops (wheel weights), indoor firing ranges, battery recyclers, and so on... your creativity is the limit. Y ou can easily melt it and pour it into a wooden box form or a coffee can. Put those in your bilge as they are clean, odor free, dry, and very easy to carry and stow. If you are really obsessed, you can make molds that fit between your frames just so, and each pig will fit perfectly.
Lead shot in inner tubes (I love that idea, Delfin) or lead pigs are also easy to adjust, and easy to remove when you want to clean or paint the bilges.
In a Grand Banks, knock-downs, broaching and pitch-poling are remote possibilities, so attaching the ballast, or pouring it in place are probably not going to be required.
A final thought, perhaps the design team at Grand Banks or the Grand Banks Owners Forum could provide more specific information.
As you say, it is always a good idea to visualize your boat rolling through 360 degrees to imagine what shifts or goes flying when it happens.
Or picture the Ekones chairs in a Nordhavn flying through the windows when a major roll occurs, say 69 degrees in an Australia bar crossing locale.
Personally I wouldn't be adding any ballast without consulting a naval architect, better yet the one who designed the boat. And yes, ancora, that would be correct, there's always some compromise involved.
If the vessel is made to sit on her design waterline with the addition and the ballast is added below that waterline, any naval architect I can think of would likely say "why not?" wouldn't they? How does lowering the center of gravity present a problem? I asking, not arguing, by the way.Personally I wouldn't be adding any ballast without consulting a naval architect, better yet the one who designed the boat. And yes, ancora, that would be correct, there's always some compromise involved.
Probably not much of an issue with a Grand Banks. Quite a few of them around. The Altair sank because crab pots were loaded on until the vessel was at an erroneously painted higher water line. This was not adding ballast as the OP suggests he is doing but adding significant weight above the center of gravity. Apples and oranges. Even if the waterline were too high on this vessel, adding weight in the bilges is only going to increase, not decrease stability. It may slow the vessel down, but it won't make it less stable.Didn't the Alaskan crab boat, Altair, sink in 1983 because somebody inadvertantly raised the bootstripe? The boat apperantly got loaded to its usual level (as indicated by the waterline) and sank because of instability issues.
That story would make me want to confirm that previous owners hadn't raised the bootstripe before adding significant ballast.
Probably not much of an issue with a Grand Banks. Quite a few of them around. .......
If the vessel is made to sit on her design waterline with the addition and the ballast is added below that waterline, any naval architect I can think of would likely say "why not?" wouldn't they? How does lowering the center of gravity present a problem? I asking, not arguing, by the way.
for the same reason people add stabilization to boats that are never sold with them.....
I am thinking of adding some ballast to my port quarter- stern. Reason being is 300' of chain in the forward locker and the slight tendency to sit starboard a little. I think the starboard slight list is because the aft head, the galley, and the lower helm are all on starboard side. I have had two people stand on the port side of the swim platform and it sits completely level so maybe 450 lbs or so would do it. Not trying to change the original dynamics, just offsetting added on items that threw it slightly off. I am still way good on waterline, stability, etc.
Jeff
I am thinking of adding some ballast to my port quarter- stern. Reason being is 300' of chain in the forward locker and the slight tendency to sit starboard a little. I think the starboard slight list is because the aft head, the galley, and the lower helm are all on starboard side. I have had two people stand on the port side of the swim platform and it sits completely level so maybe 450 lbs or so would do it. Not trying to change the original dynamics, just offsetting added on items that threw it slightly off. I am still way good on waterline, stability, etc.
Jeff
I don't know. When I bought her, she was stripped empty, although the P.O., who was a naval architect, placed a few tons in the compartment forward of the 600 gallon potable water tank, below the sole in the forward cabin. After filling her back up again, I needed to add another couple tons on the starboard side in the ER for trim.It is not just stability and trim that need to be considered when adding / removing ballast-it is where you place it low of course is better but as mentioned above placing weight on one end to counter a weight on the other may create some major back breaking problems. The center of buoyancy and gravity will be altered. Imagine the longitudinal forces at work when the wave distances lift both the bow and stern at the same time and the forces trying to break the boat in half or the other way around where the top of wave is in the middle of the boat and you have too much weight in the bow and stern. All the calculations that the NA would perform can be found in "Stability and Trim For the Ships Officer" by John Ladge. Great reference.
Delfin: On this subject was the original lead ballast on the Delfin placed in the Grey Water Tank? I found it there on her sister.
If you have the same compartment forward I have, it is ideal for ballast.I found about a ton and a half in the grey water tank (lead ingots) will probably have to add more since I took the crows nest/mast down. Glad the lead was not placed in the fresh water tank.