[C320-list] Leak in bilge

[Chris Burti]

Murphy, may or may not, have been a sailor...but he was, in fact, an engineer...

http://en.wikipedia.org/wiki/Edward_A._Murphy,_Jr,.



On Sun, Jan 23, 2011 at 10:30 AM, Bruce Heyman <bruceheyman at cox.net> wrote:
> Allan,
> I love that quote and your law.  I've found throught out my life that I've
> done most jobs twice, probably good thing I didn't choose to become a
> surgeon.  I've also found that when I've really screwed something up all I
> have to do is point out that Sailor Murphy is a permenant member of our
> crew.
> Best,
> Bruce
> Somerset 671 SoCal
>
> Bruce Heyman
> (949) 289-8400
> BruceHeyman at cox.net
>
> -----Original message-----
> From: "Allan S. Field" <allan.field at verizon.net>
> To: C320-List at Catalina320.com
> Sent: Sun, Jan 23, 2011 13:42:46 GMT+00:00
> Subject: Re: [C320-list] Leak in bilge
>
> Bruce - To paraphrase Winston Churchill, I can always be counted on to do
> the right thing but only after I have tried everything else.  I call it
> "Field's Law of Doing Stuff": If I have a 50/50 chance of doing something
> right or wrong the first time, 90% of the time I will do it wrong the first
> time!
>
> As for the torque wrench, I could not get the bolts to stop weeping with the
> boat in the water.  Of course it stopped with the boat out of the water
> (grin!) but seriously, my memory is that I could not get the torque wrench
> to "snap" which was telling me that I had not gotten the bolts to the right
> torque.  At the end of the day, thank goodness this only has to be done once
> and is not another opportunity for me to screw (pun intended) it up again! -
> Allan
>
> -----Original Message-----
> From: c320-list-bounces at lists.catalina320.com
> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Bruce Heyman
> Sent: Saturday, January 22, 2011 8:40 PM
> To: C320-List at Catalina320.com
> Subject: Re: [C320-list] Leak in bilge
>
> Alan,
>
> Yikes.  I definitely would not loosen all of the keel bolts while the boat
> is in the water; it will weep as you say.
> While I have deep respect for Gerry Douglas and he is an excellent naval
> architect/engineer I don't understand the reason to be loosening all of the
> nuts at once.
> The reason you loosen them before you tighten them is you want to make sure
> they are able to move freely. Typically when you go to loosen them it may
> actually take more than 235 foot pounds to loosen them because they are
> stuck (just hope they are not galled).  Some people think that after you
> clean them up you should oil them.  If you do oil them conventional wisdom
> is that you should reduce the torque setting by 20% to compensate for the
> reduced friction.
>
> Weather you do this job on the hard in the water I would recommend against
> loosening them all at the same time.  I've had to redo a couple of keel hull
> joints.  They are typically bed with either 5200, epoxy or an epoxy paste.
> The purpose of the bedding is to keep the keel bolts 100% dry as they are
> SS.  SS degrades very rapidly if it is held in trapped water that can't get
> oxygen.  If you only loosen one nut at a time you are less likely to disturb
> the keel's epoxy/5200 "gasket".
>
> As to why you couldn't get to 235 foot lbs when in the water vs. on the hard
> I don't understand what was going on.  235 ft lbs is 235 ft lbs regardless
> of where you are...the torque wrench just knows you got to push on it really
> really hard, it doesn't know if the boat is in the water or on the hard.
> You either have to push 235 lbs on a 1 foot wrench or 117.5 lbs on a 2 foot
> wrench or find a pipe that makes the wrench 4 feet long and then you ONLY
> have to push 59 lbs.  Be glad that Gerry didn't specify 1.5" keel bolts!
>
> Glad you bilge is now dry!
>
> Best,
> Bruce
> Somerset #671 SoCal
>
>
>
> -----Original Message-----
> From: c320-list-bounces at lists.catalina320.com
> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Allan S. Field
> Sent: Friday, January 21, 2011 3:59 PM
> To: C320-List at Catalina320.com
> Subject: Re: [C320-list] Leak in bilge
>
> Bruce - If you aren't a mechanical engineer, your prose below would fool me!
> But I do think that one point is missing.  I remember Gerry telling us to
> loosen all the bolts at one time then torque them down one at a time.  While
> I don't begin to understand the physics of what you describe below (or
> whatever science you are going by!), if I heard Gerry right, I have a hard
> time seeing how one could get the keel bolts tightened to the proper load.
> But if I heard Gerry wrong, then I accept what you say below at face value
> only 'cause I don't understand hardly a word of it!
>
> Now if wisdom is nothing more than what is left over after all the mistakes
> have been made, let me now give you the value of my hard-earned wisdom.  I
> loosened all bolts at one time with the boat in the water (note that I slept
> through most science classes in school and totally failed to think this
> through before starting...).  As hard as I tried with the torque wrench, I
> could not get any bolt to 235 foot pounds.  So now I have all keel bolts
> weeping instead of just the one I started with.  After hauling and blocking
> the boat, getting the proper torque was a piece of cake and not a weep
> since! - Allan
>
> -----Original Message-----
> From: c320-list-bounces at lists.catalina320.com
> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Bruce Heyman
> Sent: Thursday, January 20, 2011 1:28 AM
> To: C320-List at Catalina320.com
> Subject: Re: [C320-list] Leak in bilge
>
> I'm not a mechanical engineer but this problem intrigues me.  I believe it
> does not really matter if you tighten the keel boats in the water or on the
> hard. As my brain at this point can only remember that in some point in the
> distant past I took physics I hope I'm not totally botching the concepts.
> In no particular order:
>
> 1) The keel bolts do hold the weight of the keel, but more importantly they
> compress the area between the keel and the bilge putting the keel trunk in
> compression. 2) The high torque requirement, 235 foot pounds, is to perform
> item one
> above and does so by stretching the stainless steel bolt.  Hard to believe
> that a 1" SS bolt stretches but it does and I believe this would be called
> preload.3) The bolt and nut is a machine that provides significant
> mechanical
> advantage.  Basically the threads form an incline plane making it much
> easier to turn the nut compared to the lateral forces generated along the
> axis of the bolt.  Thank you Archimedes (wonder if he was a boater?).4) The
> torque measurement is not only a measure of the work done in the
> machine (threads) but also the friction on the nut face and the surface of
> the threads.  That is why it is important to take the nut off, clean both
> surfaces and make sure they are dry and free of contaminants.
> 5) If the breaking strength of a 1" - 8 threads per inch bolt is 60,000 lbs
> the clamping or preload would be 14,992 lbs when torqued to 249 ft LBs.
> 6) As our keels only weigh 4400 lb's this means that one bolt when properly
> adjusted would be able to hold the weight of more than three keels.
> 7) As we have multiple keel bolts, all torqued to 235# the preload more than
> swamps out the relatively trivial weight of a single keel.  I don't remember
> how many keel bolts we have but if we have 6 then the total preload is a
> staggering 90,000 lbs.  This is 20 times the weight of our keels.
>
> Maybe I'm all wet (pun intended) but I believe you are free to torque your
> keels in the water.  Furthermore it is safe to remove one nut at a time and
> clean it up before you reinstall it and torque it to 235 ft lbs.
>
> Bruce
> Somerset #671 SoCal
>
> -----Original Message-----
> From: c320-list-bounces at lists.catalina320.com
> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Allan S Field
> Sent: Sunday, January 16, 2011 11:04 AM
> To: C320-List at Catalina320.com
> Subject: Re: [C320-list] Leak in bilge
>
> Bruce - you are correct in that the Association has the torque wrench and
> sockets to tighten the keel bolts. However, the boat must be out of the
> water with at least 70% of it's weight supported by the keel. Think about it
> - if the boat is in the water and the weight of the keel with a gravity
> assist is pulling the keel down, what torque wrench and what sailor have the
> strength to pull that puppy up?! In fact, the bolts first get loosened
> before torquing. And yes, loose bolts do weep and need to be torqued after
> the first year then never again, at least according to Gerry Douglas. -
> Allan
>
> Allan S. Field
> Sent from my iPad
>
> On Jan 16, 2011, at 1:27 PM, "Bruce Heyman"<bruceheyman at cox.net> wrote:
>
>> Can be tightened in the water.  The Association has the equipment you need
>
> to do this job.  I thought the manual said to tighten them after the first
> year and then you were done forever.
>>
>> Bruce
>> Somerset 671 SoCal
>>
>> Bruce Heyman
>> (949) 289-8400
>> BruceHeyman at cox.net
>>
>> -----Original message-----
>> From: Kurt Budelmann <krbmd77 at charter.net>
>> To: "Catalina320.org" <C320-List at Catalina320.com>
>> Sent: Sun, Jan 16, 2011 18:02:06 GMT+00:00
>> Subject: [C320-list] Leak in bilge
>>
>> Hey, I am having a slow leak in the bilge right by the bilge pump.  No
>
> collections of water fore or aft of this location.  Can water leak down from
> top of mast?  Can water leak from the keel bolts?  Also there is a floor
> joist crossing at that location but I can find no evidence of leaks from
> ports.  I don't think keel bolts were ever re- tightened and the boat has
> never been out of the water since original launch.  Can the bolts be
> tightened in the water or does the boat have to be on the hard?
>>
>> Kurt R Budelmann
>>
>
>



-- 
Chris Burti
Farmville, NC