Forums > Sailing General

Keel bolt length in keel

Reply
Created by saltiest1 A week ago, 7 Aug 2019
saltiest1
NSW, 2055 posts
7 Aug 2019 11:16PM
Thumbs Up

Hi guys.
Someone in the list of previous owners of my s&s 39 thought it wise to add a new and extended keel to 2.4 metres draft.
Lately ive been toying with the idea of shortening this keel to the original design but I'd need to find out the length of the bolts inside.

Any ideas how?

Craig66
NSW, 1736 posts
8 Aug 2019 12:02AM
Thumbs Up

Xray

stud finder

drill a pilot hole down the centre of a bolt

drill small holes in the keel down along the line of the bolt until the drill passes below

southace
QLD, 4073 posts
8 Aug 2019 1:06AM
Thumbs Up

If it's lead wouldn't it be easier to cut it off the bottom? Can shape it with electric plane and add the offcut to each side and fair to create a bolb.

boty
QLD, 508 posts
8 Aug 2019 8:00AM
Thumbs Up

Select to expand quote
southace said..
If it's lead wouldn't it be easier to cut it off the bottom? Can shape it with electric plane and add the offcut to each side and fair to create a bolb.


sounds good to me

Yara
NSW, 866 posts
8 Aug 2019 10:05AM
Thumbs Up

It would be important to try to find out how the previous owner did it. Did they add more lead in the bottom? Did they replace the whole keel?
Why do you want to cut it back? Are there signs of failure?

Andrew68
VIC, 256 posts
8 Aug 2019 10:37AM
Thumbs Up

Out of interest which S&S 39 do you have ?

I would have thought that most likely, the previous owner kept the same ballast weight, but moved it lower when they extended the keel. The second option is that they used less the ballast. Either way just cutting 0.5m of the bottom is probably going to make the S&S 39 quite tender compared the original design.

A

Yara
NSW, 866 posts
8 Aug 2019 10:45AM
Thumbs Up

Adding a longer keel not only increases the load on the keel bolts, it increases the load on the hull joint. This could be more of a worry.

saltiest1
NSW, 2055 posts
8 Aug 2019 4:08PM
Thumbs Up

It's a different keel from the original with very solid hull connection and seal. Was originally 2.1 meters and now 2.4 but for cruising would like it back to 2.1 or 2. It has also thrown weight forward with about 40mm deeper in bow than on stern. Sails so nicely but would like easier access to cruising grounds. Compromise again.

boatbroke
NSW, 5 posts
9 Aug 2019 7:10PM
Thumbs Up

Hi Saltiest,

Keel bolts will attach to keels in a few different ways. Sometimes they wind in (with various attachment systems) and sometimes they are set in permanently. It is not how far the bolts go in lead for a deeper or a heavier keel, but more the gauge/number of bolts used at higher loads. Normally bolts will be set in 100mm-200mm.

See example here sailboatdata.com/sailboat/ss-34 (the 39 didn't show it)

And specs for the 39 here sailboatdata.com/sailboat/ss-39

From the site there was a number of different set ups that came out. Assuming that the framing/structure has been strengthened to take the extra loads if it has survived all this time.

Sometimes there is a "dead wood' section that is sandwiched between the hull and the lead too. This is normally made from a solid piece of timber (Oregon usually) and is glassed over. A tap test will show this from the outside will show where the lead starts and looking at the sump depth compared to the top of the lead from the outside will show if there is a deadwood sump section. If this is the case, there will be very long bolts from the inside of the hull/sump, through the dead wood and the standard 100mm-200mm into the lead.

If it is a deeper keel set up there invariably will be a bigger rig set up to balance it/justify the change. Assuming they were looking for better race speed/rating at the time???

I'd make super sure of the set up. A small amount of lead (100kg-300kg) removed or depth taken off makes a huge difference on the feel/balance/righting moment of a boat.

I know it is a compromise whilst cruising, but if it sails well that is the main thing. If it ain't broke don't fix it.

Great boat by the way mate, good all rounder.

Best of luck!

Adam

saltiest1
NSW, 2055 posts
10 Aug 2019 6:09PM
Thumbs Up

Thank so much for that info.
Shes done 2 Hobarts hence the lengthened keel and sails so nicely. Still wouldn't mind shaving a little off though.
I'll chase up more history of the keel and boat before I move forward. The change to a cutter rig is first but the keel a close second.

sirgallivant
NSW, 1433 posts
Thursday , 15 Aug 2019 7:42AM
Thumbs Up

Reduceing it back from 8 feet to 7 feet? Hmmm.
If one would think about making it a shoal draught - crazy as it sounds - may be - but getting into all that trouble for virtually no gain...?
Hmmm. Ughh.

Yara
NSW, 866 posts
Thursday , 15 Aug 2019 9:23AM
Thumbs Up

Select to expand quote
sirgallivant said..
Reduceing it back from 8 feet to 7 feet? Hmmm.
If one would think about making it a shoal draught - crazy as it sounds - may be - but getting into all that trouble for virtually no gain...?
Hmmm. Ughh.



+1



Subscribe
Reply

Forums > Sailing General


"Keel bolt length in keel" started by saltiest1