Core rot under the Sampson Post

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cruiserpete
Posts: 133
Joined: Tue Feb 05, 2013 5:20 pm

Core rot under the Sampson Post

Post by cruiserpete »

Hi all,

My refurbishment was going as planned and on track until I went to install a new Sampson post and when I was tightening it down the bow deck area was compressing. Thinking to myself... Hmmm, that's not a good sign I promptly undid the Sampson post, grabbed a hammer and unfortunately, I got a dull thud instead of a nice ping when tapping the area.

This is something I would not have felt comfortable working on but after spending the last 7 months refurbishing my Investigator 563 I'm pretty confident to now tackle most if not all jobs.

I mapped out the differential in noise as much as I could using a hammer and then proceeded to cut out the top layer of glass to get at the rot. My newly acquired 'multitool' was simply fantastic as it cut through the top layer of glass but not through the bottom layer.
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The next photos say it all.... rotten to the core

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Some cleaning with the multitool and some more digging got me to dry wood, thank goodness it was only a few cm from my initial cutout. The area was cleaned up to get me back to glass on the base and top.
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I force filled the small gaps between the bottom and top layer of fiberglass that I did not cut out but gouged out with an epoxy/filler mix via a large syringe.
I then cut out a new 4mm marine ply core piece, did a dry fit and fine tuned its shape. I wet the ply down with unfilled epoxy mix and bonded the ply to the bottom layer of decking fiberglass with a lightly mixed epoxy/filler combination. Then once the new core was in, I mixed a heavier but still 'fluid' epoxy/filler mix and poured that down to fill the seams.

Once the seams were thoroughly filled with the epoxy/filler fluid mix I epoxied the top fiberglass piece back on top. To hold the fibreglass top piece in place I screwed a scrap piece of wood to the deck, wedges a firm piece of rubber underneath the wood and used it as a fulcrum to press the top layer to the marine ply to the bottom layer.
Once the mix has cured, I'll add a little bit of fairing, some primer and a quick 2 pack paint touch up and I'll be able to reassemble my Sampson Post again
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Feeling confident that my work should reap rewards but I'll soon know tomorrow when I take the fulcrum off to check. So far so good (I think)

UPDATE 2:

Part 2 of the rotten deck refurbishment was to glass over the refurbished rot area on the bow simply to give the refurbished rot area more strength.
Had to Feathered out the edges to allow the glass to be layered up.
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I'll start layering the glass/epoxy tomorrow only because I ran out of epoxy today lol

UPDATE 3:
Rot refurbishment area now covered with 3 progressive layers of fiberglass ( using polyester resin because the local West epoxy dealer only orders in and does, not stock it yet he is a dealer). The polyester resin will be ok because I ground back to the original polyester resin/fiberglass to give me a good working surface. Would have preferred epoxy but feel confident this will be sufficient.

I'll sand down to give be the required finish, fair it off and whack on a lick of 2 component primer and then paint. Then reattach the Sampson post. I feel confident that this fix will help me sleep well at anchor although, I'll not actually sleep well at anchor lol

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Cheers, Pete
Last edited by cruiserpete on Sun Sep 24, 2017 3:38 pm, edited 5 times in total.
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Andrew
Posts: 541
Joined: Sun Aug 18, 2013 11:33 am
Investigator Boat Name: Teria
Location: Townsville, Qld
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Re: Core rot under the Sampson Post

Post by Andrew »

Hi Pete,

Thanks for the post. Now i finally know what the deck core is made of! - plywood.

My decks have some spongy spots..been putting up with it.

Although this may not work under a compression fitting, (?) i spotted a product called "injecta-deck" a hard foam filler applied through small drillholes in the deck.. it costs a few hundred $ from the states..

Cheers

Andrew
Andrew

Investigator #9 Teria
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Ozzie
Posts: 1621
Joined: Wed May 27, 2009 1:07 pm
Investigator Boat Name: Spritzig II
Location: Lake Macquarie
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Re: Core rot under the Sampson Post

Post by Ozzie »

This is a mildly terrifying thread considering the age of all our boats . It's good to see that it can be tackled albeit with considerable work . I guess monitoring is the key . Which reminds me I have not checked the foredeck for a few years and as I'm moored it's rather important. Threads like this need a bump occasionally :shock: .
Ozzie
Investigator #143 "SPRITZIG II"

The Mariner - “It’s too strange here. It doesn’t move right." ...
Enola - “Helen said that it’s only land sickness."
Waterworld (1995)
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Ozzie
Posts: 1621
Joined: Wed May 27, 2009 1:07 pm
Investigator Boat Name: Spritzig II
Location: Lake Macquarie
Contact:

Re: Core rot under the Sampson Post

Post by Ozzie »

I assume it's the same for all viewing this thread but Petes original photos now come up only as a message from photo bucket? This is an issue with old photos and a warning to make a copy of anything you want to keep as a record particularly with instructional stuff.

One of the really annoying things about the www is how offsite photos on forums disappear as the hosting site has a sunset period but look up a council event like the nye fireworks and you get confused by ads going back to 16 BC :shock: if only they cleared out the chaff and left the stuff you want :(
Ozzie
Investigator #143 "SPRITZIG II"

The Mariner - “It’s too strange here. It doesn’t move right." ...
Enola - “Helen said that it’s only land sickness."
Waterworld (1995)
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