Bilge moisture question

[partingclouds]

A few days ago l was poking around the bilge, inspecting the keel bolts. All looked nearly pristine, except for the pair just aft of the mast. One of them is weeping a very small amount of water. But, not constantly, as yesterday it was dry.

A boat builder pal (as in wooden boats) suggested l should just tighten the nut. I'm wondering if l should, and hoping that it doesn't just worsen the situation. My gut says this would be better done on the hard. But, what do l know...

[boatpoker]

Photo of the suspect bolt may help.

[massnspace]

I have tightened bolts (several times) when the boat was in the water. I don’t think you will hurt anything….

[barnakiel]

The point is however to stop water ingress into that area.


Which is done while the boat is at rest, dry - in the boatyard.


The bolts get tightened at the same time - if you discover they are not tight enough.


You are not likely to make much damage if you try now - but this is not the solution to your challenge.


b.

[GordMay]

You cannot go too far wrong, following boatpoker’s advice.

If you have significantly uneven torque on the various nuts, you might want to tighten the looser one[s], to equal the tightest.


Different manufacturers specify differing torque values, for the same bolt size. This may have something to do with the differing materials, each may use, for their bolts. [I didn’t locate any spec’s, from Pearson.]:

ie: Bolt Diameter = Torque Ft/Lb [O’Day ➛ C&C]
1/2″ = 19.2 ➛ 80 [Ft/Lb]
5/8″ = 48.7
3/4″ = 90 ➛ 95.9 ➛ 250
7/8″ = 140.1 ➛ ?
1" = ? ➛ 350
1-1/4" = ? ➛ 450

[massnspace]

Originally Posted by barnakiel

The point is however to stop water ingress into that area.


Which is done while the boat is at rest, dry - in the boatyard.


The bolts get tightened at the same time - if you discover they are not tight enough.


You are not likely to make much damage if you try now - but this is not the solution to your challenge.


b.

Why not try to tighten them right now? In the water?

It’s a long short, but it is possible to stop a leak by doing this. In my situation I greatly reduced (not 100% stopped, but greatly reduced) water ingress by tightening the bolts while in the water.

I don’t think there is much chance to damage anything….just crank them down, if the nuts are still usable….

[SailingHarmonie]

You can tighten the nuts in the water without serious risk. However, there is a method to it. First, mark all the studs. If any of them turn, even a tiny bit, you’re done. You have a major repair on your hands.

Then tighten in a crosswise pattern using a torque wrench.

Finally, be aware that if there is water between the keel and hull, and your studs are stainless, they are likely corroding.

[GordMay]

Originally Posted by SailingHarmonie

You can tighten the nuts in the water without serious risk. However, there is a method to it. First, mark all the studs. If any of them turn, even a tiny bit, you’re done. You have a major repair on your hands.

Then tighten in a crosswise pattern using a torque wrench.

Finally, be aware that if there is water between the keel and hull, and your studs are stainless, they are likely corroding.

Indeed.

[partingclouds]

Thanks for each of your answers. I appreciate your kind help. I'll post a pic that may shed some light on the situation.

[capt jgw]

If the bolt(s) are leaking, they are wet down where they are buried in the fiberglass. As mentioned above if they are any grade of stainless they could be suffering from crevice corrosion. Bronze not so much, galvanized probably worse. They can look fine on top where you can see them but corroded to near nothing below. Or vice versa. Tightening the bolt may prevent seawater coming into the bilge but it will not prevent it contacting and corroding the shaft of the bolt. Tightening is a temporary fix and the bolt could break off when you do it. Been there done that. The permanent fix is to haul the boat then drop and rebed the hull/keel joint and inspect/replace the bolts as needed.
Another factor is whether the keel itself is lead or iron which determines how the bolts fasten to it. If iron they are just regular bolts tapped into the iron and can easily be unscrewed and replaced. If lead, they are most likely "J" bolts cast into the lead and cannot be removed by any practical means. The only builder I know of that used another method was Columbia, some of their keels were a harder alloy of lead and the bolts were hanger bolts screwed into that. Those are easily replaceable.

[GordMay]

Originally Posted by capt jgw

...
Another factor is whether the keel itself is lead or iron which determines how the bolts fasten to it. If iron they are just regular bolts tapped into the iron and can easily be unscrewed and replaced. If lead, they are most likely "J" bolts cast into the lead and cannot be removed by any practical means...

The Cooper/Martin Doug Peterson 35 [“Ganbare”] had 6,500 lb [2,948 kg] of lead ballast.