keel ballast?

[yourmomm]

after some effort, i just opened up my bilges on my (10ton!) inherited boat for the first time and found 7 huge steel (?) blocks lying loose in the centre-bilge; they must weigh 30-40kg each and theyre just lying there-loose and rusting. is this normal? i am tempted, at even more effort, to remove them and believe the keel itself is heavy enough to do its job, or am i just stupid...?!

 

[Porthandbuoy]

Only 7?
My Hillyards got a couple of dozen lead toblerones.

It's not uncommon for classic wooden boats to have "trimming" ballast. It's a sort of euphanism for "the designer and/or builder got it wrong and she didn't quite sit to her marks". To be fair, wood tends to a bit variable in density.

 

[neil_s]

1/4 Ton or so in a 10 tonner? That sounds like trimming ballast. Its probably there to balance out some other heavy weight, such as the engine. My Hilliard 8 tonner had lots more than that! It should be chocked in place between the frames and sole bearers to stop it moving in extremis. In practice that is not so easy to achieve. I found that a good coat of bituminous black paint helped, since the blocks of balast then stuck to each other and to anything else they touched.

Cheers! Neil

 

[yourmomm]

eek!! well i thought she sailed like a dog-perhaps she is under-ballasted?....so-if this isnt a stupid question-HOW do you tell how much ballast you need...?!

 

[roly_voya]

Trim ballast is just to get her level, ie if when normally loaded she sits bow up then add balast forward. Wont effect performance much. If she is under-balasted then she will not make speed particularly to windward. A rule of thumb is that you should be able to get 1x square rout of waterline length at about 45deg to apparent wind. The problem is that poor sails or sail trim will have exactly the same effect so I would advise talking to a sailmaker before looking at ballast

 

[William_H]

I will make some comments which may suggest I claim to know about stabilty design in boats which is not so however...as I see it. The balast at the bottom of the keel is most critical in improving the righting moment when the boat goes beyond around 45degrees of heel. The total balst (including keel weight and under floor balast) will improve the stiffness ie the keeping the boat upright at low angles of heel. (This is more pronounced in a hard chined boat as opposed to a round bottom)
So if you have adequate weight in the keel for self righting and can't make the keel any heavier then stiffness can be improved by balast under the floor. This may be why the iron is under the floor.
Actual sailing performance will not be improved by more balast however if the boat heels over a lot and so you get a lot of leeway then overall performance to windward will be poor. (leeway increases as the keel moves from vertical toward horizontal and so presents less resitance to sideways movement of the boat) So more balast may help.
So the boat should not necessarily sail faster with more balast in fact should sail faster when lighter but more balast may permit more sail in a good wind and so give better performance.
One might expect that balast in the bow or stern would be used to improve trim while balast midships would be to improve stiffness.
So try taking out the undder floor balast, it may help or maybe not as the case may be..olewill

 

[yourmomm]

thanks all-very helpful. Yes william H the ballast is all midships-and she DOES heel enormously in a half decent blow....ive always put this down to the travellor not being set-up correctly and have been running forwards (she is a ketch) to adjust that and give it more movement as the wind increases....i will get some more iron and see where that gets me

 

[andy_wilson]

A real seaworthy vessel would have all items and stowage secure in any event. That means inversion!

Sounds like a disaster waiting to happen should you get caught out and suffer a partial knock down. Items of that size could kill, maim or simply penetrate the hull.

You may not be expecting to cross Biscay or oceans for that matter, but a sudden downdraught from a stom cell at the height of summer after a long hot sunny weekend could put your ship on it's side, and the missiles could then put it on the bottom.

They should be secure.

You could change them for bagged gravel which would be slightly less dangerous.

 

[sarabande]

Depleted uranium is denser than gravel, and keeps you warm in winter and stops weed growing on the bottom.

 

[yourmomm]

errr......i have ALREADY crossed biscay and the channel in some pretty rough conditions and all was fineexcept for the excessive heel and leeway...i have tried lifting these behemoths and they seem pretty reluctant to budge even slightly with all the force i could muster-they are jammed in super-tight-i dont reckon they would be moving anytime soon....but just in case....anyone know where i can lay my hands on depleted uranium without having to go iraq or the lebanon...?

 

[William_H]

Some (older) boats are designed and expected to heel fairly easily to a point where they stiffen up. The shape of the bottom is the key. Wider more pronounced chines (flat bottom) giving that initial stiffness. (a catamaran is the extreme example) While a deep vee shape with little width at the chines will initially tip easily until the keel starts to be forced by gravity to stop any more heel (like a pendulum). So more balast may or may not help.

Sail condition and management will help. Too much jib and too much camber on main mizzen and jib will be a cause for excessive heeling in medium winds. It can be amazing what new sails can do. However before you go spending, make sure the main and mizzen are as flat as possible with outhaul very tight ,halyard tight, and if possible some mast bend. (inner forestay tight). And yes you should aleviate the pressure with the traveller dropped down to leeward.
(early reefing will help)
The jib is another story. It is essential to have the sheeting poinnt correct and the size of sail correct.
I am a sticker with individual jibs and find the boat much better with any wind with a smaller jib correctly tensioned and sheeted.
Anyway persevere there is no easy answer but keep trying and experimenting. olewill