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Keel Bolts and sump drain box

Getting ready to torque the keel bolts and removed this box in the bilge.  Doesn't appear to be hooked up to anything.  Perhaps it was hooked to a drain in the head for a shower.  Anyone know what was hooked up there.  Perhaps there is a drain from the icebox also in there.  Anyway I am thinking about removing it unless someone can tell me what it does?  Has anyone removed theirs and just had whatever drain in the bilge?  There was a lot of junk (dirt and debris) underneath this box so it would be a lot cleaner if that wasn't there.

I found 8 keel bolts all with 1 1/8" nuts on 3/4" bolts, anyone have anything different.  Mine is a deep keel version so perhaps the bolt pattern is different on the shoal draft boats.

Rod Stright


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That is the sump.  It should be connected to the head sink and the shower drain in the floor of the head.  That way all soap/toothpaste curd is prevented from going into the bilge.  Instead, it goes into the sump which has its own pump controlled by the switch in the sump to remove it.

The ice box drain goes directly into the bilge.  Don't spill a quart of milk or something else in the icebox that will turn nasty!

I believe the bolt pattern for both keels is the same.

Thanks Gerry, I believe the previous owner changed things around when he installed the overboard discharge and the holding tank.

I assumed there were different sized bolts in the keel but all mine were the same.

Just for clarification with respect to the keel bolts.  There are 8 and they are all 3/4" and the nuts are 1 1/8".  Suggested torque is 250 foot pounds.  We torqued ours on Saturday and the most we could get was 235 foot pounds.  They were a bit slack and the nuts moved anywhere between 1/8 and one half turn.



It is my understanding that the keel bolt specs are always given for clean and dry - no lubrication - unless the lubricant is specified. "It doesn’t really matter whether Torque Specifications are “usually” for wet (lubricated) or dry fastenings. What matters is what the specification, to which you are referring, assumes. If it’s a “wet” torque, it should also specify the particular lubricant (they have differing coefficients of friction).I believe that the FAA (for instance) states, "all torque figures, unless otherwise stated, are given with threads clean and dry*."

* Dry Torque usually assumes a coefficient of friction of 0.20, and a dry, unlubricated fastener." The forum goes on to discuss this in more detail than I understand, but my take-away is that the specified torque listed by C&C 99 is dry and that therefore the lubricated torque will be less than 250 ftlb. How much less depends on the lubricant and cleanliness of the bolts.

My husband went back over all the information he acquired over several weeks. This includes information from the C&C class forum.  His take on all the collected items that follow is that 250 ft-lbs is far too much for a 33’ sailboat: that it’s the stretch point for the bolt itself, the limiting torque value if the bolt were being used in an application that’s bolting together two pieces of solid steel, not a lead keel and a plastic, fiberglass, or epoxy boat together. For fear of pulverizing the keelson, he wouldn’t feel comfortable going beyond the 95 ft-lb range; and he not sure that from what he has learned that he would torque it even that far until the keel was no longer supporting the weight of the boat on land (because of any possible off-center pressures from perfectly square alignment). I’m thinking maybe 70-75 (some of them were only 40-50 when I checked the torque with the boat resting on keelblocks and jackstands after Fall haul-out). Then maybe tighten toward 95 (gradually and in an alternating pattern working from the middle toward the ends. Call me conservative, but reading some of these and other references, and having no prior personal experience with this, I’d stop there unless a bona fide expert said otherwise with specific reference to precisely this situation. And of course, this assumes clean and well-lubricated nuts and bolts - which may itself be a bigger project than just socking up some nuts.

Description of bolts and placements are at:

which deals with Canadian-built boats, not 99s and after

Technical Info

Lists 250 ft.lbs for 3/4” keelbolts

From the cnc99class website



Downloadable Documents

Keel Bolt Torque Specs for C&C99

says the same thing, and

April 3, 2018, 8:07 pm

I was able to come up with an answer, Special thanks to the previous owner of Demons Dance!

½” bolts: 45 ft. lbs.

¾” bolts 250 ft. lbs.

1” bolt: 350 ft. lbs.

Customer Service Manager

Tartan, C&C Yachts


from the J/24 class website (but evidently not limited to J/boats):

Checking your keel bolts should be part of your annual maintenance plan. Working one bolt at a time, remove the nut and washer and clean the threads with a small nylon or brass brush or scotch brite. Do not use a steel wire brush, as this can lead to other corrosion issues not covered here! Check for signs of rust. If everything looks good, use a generous coating of anti-galling compound and re-torque the nut. Most J/22 keel bolts are 5/8

Keel Bolt Torque Table

Bolt Diameter Torque Ft/Lb

1/2″ 19.2

5/8″ 48.7

3/4″ 95.9

7/8″ 140.1

This Table is derived from information in Table A7 from ISO/DIS 12215-9.2. These values are for well greased threads. Friction in the screw and under the bolt head makes up approximately 90% of the tightening torque and approximately 10% contributes to prestressing of the bolt. The user is cautioned to use good judgment in applying these values.

Tip- If you can pull in your mainsheet, you probably don’t need a big breaker bar to torque your nuts. Over-torqueing is extremely bad. Particularly on the bolts holding your lifting rig, under-torqueing is equally bad. If the nut is loose enough to allow movement in the bar, the bolt can be loaded unequally, leading to tension stress on one side of the bolt.

Which (95.9) is what he was told by Chris Ranney at Tartan Legacy Yachts, where the 99s were built

    • The above is from my husband. Below is the view of the forward 4 bolts which are below the sump box after first round of cleaning.
No photo description available.
Ed has continued to research the friction co efficient in order to get an accurate torque.  He has also cleaned each bolt, washer and nut and re passivated the stainless steel to prevent any future corrosion.
His more recent estimates are more in the 130 range, but has not found a friction co efficient for the lubricant.
For those of you who have already torqued your bolts according to C&C 99 original documents, no point in backing off.
Hope that this helps.

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