She's Splitting Down the Middle!

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dancrosswis
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Joined: 6/6/19
Posts: 14
She's Splitting Down the Middle!

This is a call for understanding and advice.  I don't understand what's happening or how to fix it.

What's Happening
My cabin sole is developing cracks.  The following photos are from locations 1 and 2.

Photo 1.  This is a top down view at Location 1.  I purchased Hiatus 4 years ago.  Then, this crack was limited to the recessed lip for the bilge board cover.  It was unopened.  The crack has developed up the vertical wall of the settee.  The crack opens when Hiatus is on the hard, as she is in this photo.  It closes when she is afloat.

Photo 2. This photo is from the same location, and shows a newly developed crack at the top of the settee.  I first noticed this during last fall's decommissioning.

Photo 3.  This photo is a top down look at Location 2, behind the mast.  I first noticed the cracks during last season's sailing season.  The large crack opened up when Hiatus went on the hard.

Photo 4.  This is a top down view at Location 2, but in front of the mast.  I first noticed this crack during fall decommissioning.

Photo 5.  This is a photo of the floor under the settee at Location 1.  I searched for damage below the cabin sole, as far as I could see with eyes and iPhone.  This is all I found.  I won't say my search was exhaustive.

Additional Background.  We've put a lot of miles on Hiatus in 4 years.  A semi-trailer trip from Wisconsin to Florida.  A winter in the Bahamas.  A return cruise to Wisconsin along the Great Loop.  Summer cruises in the North Channel.  I recall three bumps or groundings.  A soft grounding on Bahamian sands that a lifting tide cured.  A sharp bump and over on a granite boulder in the North Channel.  A thud, probably against a submerged log, along the Trent Severn.  None left any marks on the keel.  I first noticed the original crack (Photo 1) growing and opening when Hiatus wintered on sandy soil in a North Carolina yard 2 winters ago.

Can anyone help?

Dan Cross
sv Hiatus
Sailing from Menominee, MI
1995 C36 MKII TR/SK M-35A(C)

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Haro
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Joined: 11/7/14
Posts: 415

If I had to guess,  I would check the standing rigging. They may be too tight.

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Sojourn
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Joined: 7/14/08
Posts: 168

I would recommend have a surveyor come out and look at the damage.  He might offer a cause and remedy.  If Haro is corect, check the chain plates and their anchors.

Lou Bruska
Sojourn
1985 C-36 Mk-I TR #495
Eldean Shipyard
Lake Macatawa (Holland, MI) Lake Michigan
Rallyback@comcast.net

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pkeyser
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Joined: 5/18/13
Posts: 663

Have you tried adjusting the pressure exerted on the hull by loosening/tightening the jack stands and seeing if that makes a difference in the crack size?

Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B

dancrosswis
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Joined: 6/6/19
Posts: 14

Gentlemen,
Thanks for your comments.

Standing Rigging and Chainplates
I removed my mast and pulled my chainplate assemblies last winter.  The assemblies were showing a shade of rust from our travels in salt water and the bulkhead chainplates were leaking a bit.  I found no structural damage in the assemblies or their attachments to the hull and hull liner and, as I best I could, I reinstalled the assemblies to the tensions they had at disassembly.  It's possible I was off--or far off--the mark there.

I don't suspect that my rigging is over-tensioned.  Using a Loos tension gauge, I first tension the wires to their recommendations: 15% of breaking strength for stays and ~10% for shrouds.  This leaves minor slackness in the shrouds, which I take up when sailing.

I will say that the number and size of the cracks increased last summer, following my work on the chainplates.  Coincidence or cause/effect?

BTW, I used Practical Sailors DIY Formula Using Citric Acid for removing rust and passivating stainless.  It worked incredibly well.

Jack Stands
Hiatus slept through her winters on her cradle until I took her to Florida.  Since then, she's only had jackstands. I first noticed that the original crack was getting bigger when the boat was on the "hard" on sandy soil in North Carolina.  I had been away from the boat for about 6 months and, when I returned, I found myself taking up slack in the stands each of the first few days.  I don't remember that tightening the stands closed the crack any.  I haven't otherwise experimented with loosening/tightening the stands.  But, the cracks widen when she is removed from the water and the water pressure on the hull is removed.

Surveyor
Good call.  The original, small crack was noticed by the surveyor when I purchased Hiatus.  But, no investigation of its cause was made (or asked for by me).

I have never contacted Catalina to discuss boat issues.  Should I be pursuing that avenue for info?
 

Dan Cross
sv Hiatus
Sailing from Menominee, MI
1995 C36 MKII TR/SK M-35A(C)

dhickmanii
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Joined: 7/27/18
Posts: 31

There is a block of wood between the butt of the mast and the keel.  It rots. Once it does, this sort of damage occurs.  I'd check that out. If it were solid, I don't think your standing rigging could force you mast to crack your sole. 

David
Mobile, AL
S/V Beach Belle
1983 Catalina 36 Mk I #154

Std. Rig, Fin Keel, M25

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GaryB
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Joined: 10/26/08
Posts: 575

The mast step was a condition I had thought of but I have similar crazing cracks on my boat, no where near the magnitude of yours. I'm thinking that you may store the boat with the mast in, would that be correct? I have often thought that a boat on the hard with the mast in would vibrate and move as the wind changes occur. Couple that with incorrect hull support may exacerbate the flexing causing the crazing and in your case cracking.

Gary Bain
S/V "Gone With The Wind"
Catalina 36', Hull #: 1056, Year: 1990, Engine: M-35
Standard Rig
Moored: Boothbay Harbor, Maine
Home: Auburn, Maine

dancrosswis
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Joined: 6/6/19
Posts: 14

Gentlemen,
Thanks, again, for your comments.

Catalina
I contacted Catalina and they have been helpful.  I'm working with Warren Pandy.  He's reviewed this post, we've spoken by phone and corresponded.  This is a problem of first impression for Warren (and he's been around Catalinas a long time).  He's not sure, but suspects a knock to the keel in the past.  He plans to work up a fix schedule that should take care of the existing cracks and keep them from spreading.  I'll post updates to this thread.

Mast Step
I'll ask Warren about this.  I had an early C34 with the wood insert and I know they got rid of that within a few years.  Does anyone know whether my 1995 C36 MKII would have a wood block encapsulated in the fiberglass mast step?  I'll take a closer look, but I don't recall see any fractures in the mast step (which may be impossible to see in any event).

Mast Up Winter Storage
Yep, Hiatus is normally stored outside with her mast up.  And, the Wisconsin winter winds will blow.  That's normal.  My cracks aren't normal.  So, I wouldn't expect the former to lead to the latter.  All that sophistry said, I'll ask Warren about this, too.

Again, thanks for the ideas.

Dan Cross
sv Hiatus
Sailing from Menominee, MI
1995 C36 MKII TR/SK M-35A(C)

dhickmanii
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Joined: 7/27/18
Posts: 31

I've spoken to Warren, and he is very good, but I can promise you that Catalina 36's had wooden blocks to act as support between the mast step and keel. 

David
Mobile, AL
S/V Beach Belle
1983 Catalina 36 Mk I #154

Std. Rig, Fin Keel, M25

Attachments
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Image icon Step after wood removed. 1.84 MB
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