[Rhodes22-list] Re: HELP!! CB trunk has delaminated!
Lou Rosenberg
lsr3 at MAIL.nyu.edu
Tue Dec 7 10:29:18 EST 2004
Roger,
I like your idea and already have the cutter blades for my dremel
tool. I always wear goggles as much as I hate them since I also wear
glasses and a full respirator mask esp when working around epoxies
and sanding FRP. Thanks for the warning anyway.
But first I was hoping to show you my board pics but my drive at hm
froze so iam going to try to upload from my work computers at NYU.
The board has some flaking of extra layers of paint near the top
where the SS mounts for the two sheaves reside. I am going to
scrape and sand all that excess away. I remeasured the width last
night and believe I may have made incorrect measurements last week
which could mean the board will fit back in easier now that the small
amounts of barnacles have been removed and the front end of the trunk
has been sanded down effectively.
If the board does go in smoothly I will patch up the delaminated
section that exists and not cut out any more of the bulge this
season. If the board does not go in and out smoothly, then I will
have to cut out ONE side of the bulging cement. I don't believe the
bulging cement is that bad that it must be removed on both sides as
I said the board did come out with only one person pulling it up once
it was unstuck below. This could have been due to growth on the
trunk compounded by the swollen cement intrusion.
I will make inquiries into the list of surveyors who i solicited
originally and see what their prices are for doing the ultra sound
test you recommended. As a related item, when I was underneath the
cabin/ companionway section of the hull Sunday, I did some knocking
on the hull and found disparate sounds coming from my port side as
compared to my stb side, in the same horizontal plane. When I took
notice of where this correlated back to upsides, I found it to be the
region where I have noticed some of my cement ballast eaten away by
water damage. This pic is online but the damage seemed localized
and I have no idea how far back the cement ballast continues past the
companionway. But an ultrasound test would help determine the state
of the lamination if I understand your post correctly.
thanks for all your help!
peace
Lou
> Lou,
>
>Could you get into your centerboard trunk with a small circular saw blade
>chucked up in the flex drive on the Dremel Multitool? I have a fine tooth
>circular saw blade for my Dremel Multitool with a 1 inch OD. With the close
>clearances inside the centerboard trunk & a bare spinning blade, I think I'd
>wear a HD glove (preferably Kevlar or chain mail!) on the hand that was
>holding the flex drive & you'd definitely want eye protection. If there is
>sufficient room & you think you can do it safely, you could cut thru the FRP
>laminate all around the bad area. Once you have the FRP laminate cut, you
>should be able to get behind the laminate with a chisel & peel it away from
>the cement. Once the FRP skin is removed, you will probably be able to
>quickly remove the extra bulging cement with the chisel as well.
>
>If it was my boat, before I started cutting, I would try to do some
>nondestructive testing to see if there are any other bad areas in the
>centerboard trunk. Look in the Yellow Pages under "Laboratories-Testing"
>and also under "Surveyors-Marine". You are looking for someone that can do
>nondestructive ultrasound. If I were doing this testing, I wouldn't need
>anything fancier than a signal generator, the handheld ultrasound transducer
>& an oscilloscope. What you are doing is really just a thickness test.
>Good FRP laminate will give a nice clean echo pulse off the FRP/cement
>interface at the centerboard well skin & also at the FRP/cement interface on
>the outer shoal draft keel skin. But, you will also get echo pulses off any
>delaminations, voids or porosity (either air or water filled), regions of
>high density in lead/cement filler, & regions of low resin saturation in the
>FRP laminate. The overall echo pattern on the oscilloscope screen will
>probably be very complex. But, you don't need to explain every little blip
>on the oscilloscope screen. You are really just interested in comparisons
>of good/bad areas in the FRP laminate - i.e. areas where the short return
>time echo pattern is significantly different than the echo pattern in other
>areas of the centerboard well. An hour of time scanning the interior
>surface of the centerboard well could be very revealing, showing areas of
>thin FRP laminate, delamination, water intrusion, porosity, & poor resin
>saturation. Then, you could confidently cut out all the bad areas & fix
>them. Around here, there are outfits where I could rent this equipment for
>a couple of hours. Actually, I'd just borrow it from the SVSU materials
>testing lab!
>
>Unless an inspection of the centerboard reveals it has some bulges, cracks,
>or other flaws, I wouldn't start modifying it.
>
>Roger Pihlaja
>S/V Dynamic Equilibrium
>
>
>----- Original Message -----
>From: "Lou Rosenberg" <lsr3 at MAIL.nyu.edu>
>To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
>Sent: Monday, December 06, 2004 1:46 PM
>Subject: Re: [Rhodes22-list] Re: HELP!! CB trunk has delaminated!
>
>
>> Roger,
>> I soon realized that I would never want to use a Sawsall on the
>> trunk! A drill to pierce the thin layer of FRP that has bulged
>> outward and then a few taps w a strong wood chisel would do .. The
>> manufacturer didnt lay up any glass mat there .
>>
>> Lou
>>
>>
>>
>>
>> > I now realize that a sawsall on just one side of the trunk might
>> >give me enough room and then all I have to do is re seal and re
>> >glass the trunk but that is still alot of work compared to doing
>> >just the board.
>> > My initial measurements on the trunk told me that I only needed
>> >about 1/16" more clearance total to make the board move freely.
>> > I have also thought about adding a emergency release on the top of
>> >the cap . Basically a spring loaded rod attached with a rubber
>> >piece that contacted the back of the board that would help it
>> >release if it got stuck during the season. What do you think of that
>> >idea?
>> >
>> >more info later,
>> >Lou
>> >
>> >>GBI did not build the early Rhodes 22's in-house. Instead, the
>construction
>> >>was out-sourced to a number of contract boatyards. The quality of
>> >>construction at some of these boatyards was not of a very high standard,
>> >>which is why Stan eventually started building his own boats in-house.
>This
>> >>is also why GBI will not recycle & warranty Rhodes 22's from this era.
>My
>> >>fearless hypothesis regarding the problem with your centerboard trunk is
>> >>that the FRP laminate was too thin &/or of poor quality. Water has
>leaked
>> >>into the cement thru this questionable FRP laminate. Over time, this
>water
>> >>has reacted with the residual Portlant cement & expanded to give you the
>> >>bulge we observe today.
>> >>
>> >>My initial reaction is that you are going to have to grind away the bad
>FRP
>> >>laminate in the centerboard well + some cement. Then, you are going to
>have
>> >>to rebuild the walls of the centerboard well with new FRP laminate.
>Ugh!
>> >>
>> >>Let me think about this problem a little more?
>> >>
>> >>Roger Pihlaja
>> >>S/V Dynamic Equilbrium
>> >>
>> >>
>> >>----- Original Message -----
>> >>From: <steadilsr at verizon.net>
>> >>To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
>> >>Sent: Sunday, December 05, 2004 9:11 PM
>> >>Subject: [Rhodes22-list] Re: HELP!! CB trunk has delaminated!
>> >>
>> >>> Roger, Todd , Peter T and all Rhodies:
>> >>> Need advice on pics being posted.
>> >>>
>> >>> After pulling out the stuck CB last week I decided to use my dremel
>tool
>> >>> attached to a flex shaft & 120grit sand minidrum to shave about 1/16
>" of
>> >>the
>> >>> fibreglass away which is bulging out into the upper trunk.
>> >>> During the wk I carefully measured the CB thickness using two
>straight
>> >>edges
>> >>> for references I meas the distance btw the edges along the length of
>the
>> >>> board.
>> >>> i then cut strips of plywood conforming to those depths as test
>sticks.
>> >>I
>> >>> used those depth sticks today to measure how much glass i was
>trimming
>> >>away
>> >>> with the dremel.
>> >>> Its diff to photograph but my trunk as it has 2 apparent sections
>of
>> >>depth.
>> >>> The upper trunk where the lip is sealed with the neoprene and the
>lower
>> >>> section which opens to the sea. My lower section is not bulging and
>there
>> >>is
>> >>> plenty of room, but the upper is too tight.
>> >>> After sanding the head of the board down I was able to drop the
>depth
>> >>stick
>> >>> in and moved on to the middle of the board. The section to the rear
>of my
>> >>> pivot was tighter and soon I foung my wall had cracked and the glass
>> >>crumbled
>> >>> away revealing the dry cement. I know how to patch the hole with
>epoxy,
>> >>but
>> >>> now I cannot sand the walls with out risking similar problems.
>> >>> I am posting my pics for reference and will have more next week.
>> >>> Any advice welcomed.
>> >>>
>> >>> note: Even if a surveyor had told me not to buy this boat due to a
>stuck
>> >>cb,
>> >>> i think i would have gone agains his advice due to the condition of
>the
>> >>hull
>> >>> and other parts. I am still convinced my boat will sail this summer!
>> >>> Lou
>> >>>
>> >>
>> >>
>>
>>>--------------------------------------------------------------------------
>--
>> >>----
>> >>
>> >>> Name: 16 w ruler CU..jpg Type: image/jpeg Size: 135840 bytes Desc:
>not
>> >>available
>> >>> Url:
>>
>>>http://www.rhodes22.org/pipermail/rhodes22-list/attch/200412/05/16wrulerCU
>..
>> >>jpg
>> >>>
>> >>
>> >>
>>
>>>--------------------------------------------------------------------------
>--
>> >>----
>> >>
>> >>> Name: Str down trunk no dam vi.jpg Type: image/jpeg Size: 134960
>bytes
>> >>Desc: not available
>> >>> Url:
>>
>>>http://www.rhodes22.org/pipermail/rhodes22-list/attch/200412/05/Strdowntru
>nk
>> >>nodamvi.jpg
>> >>>
>> >>
>> >>
>>
>>>--------------------------------------------------------------------------
>--
>> >>----
>> >>
>> >>> Name: MCU galley flr.jpg.jpg Type: image/jpeg Size: 138460 bytes
>Desc:
>> >>not available
>> >>> Url:
>>
>>>http://www.rhodes22.org/pipermail/rhodes22-list/attch/200412/05/MCUgalleyf
>lr
>> >>.jpg.jpg
>> >>>
>> >>
>> >>
>>
>>>--------------------------------------------------------------------------
>--
>> >>----
>> >>
>> >>> __________________________________________________
>> >>> Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
>> >>
>> >>
>> >>__________________________________________________
>> >>Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
>> >
>> >__________________________________________________
>> >Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
>>
>> __________________________________________________
>> Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
>>
>
>
>__________________________________________________
>Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
More information about the Rhodes22-list
mailing list