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removing a cockpit sole :: replacing rotten wood

8K views 23 replies 11 participants last post by  asdf38 
#1 ·
I know I'm following a time honored path for owning a boat and boat repair - Start a project and it expands into something all together different that challenges your skills, patience, cash flow and domestic harmony.

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I'm on the verge of venturing into an area of carpentry and boat repair I'm not totally comfortable with. I think I have to pull off the cockpit sole of my 18 foot Marshall and replace the structural supports that are either saturated or rotten. I'll need to then put it all back together.

Spec: 1976 Marshall Sanderling (18') w a Westerbeke 7 diesel (removed).

It began with an electrical fire
(http://www.sailnet.com/forums/diesel/209817-remove-old-inboard-keep.html).

I've had the engine pulled and have been cleaning the engine box
(http://www.sailnet.com/forums/gear-maintenance/229225-advice-cleaning-engine-box-bilge.html).

Over the course of scrapping paint and inspecting I've found that the wood that is the engine box was not encapsulated with epoxy and is now saturated wet or rotten. The tabbing has separated from the wood in several places. The wood behind the tabbing is some of the most rotten where the water has gotten in and sat. This is more pronounced on the starboard side.

The struts for the motor mounts look like they haven't been affected, which is good news to me.

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So, I'm looking at a boat I really love; considering starting something I don't know how to approach and if I'll have the where-with-all of time, money and skills to complete. I'd like some thoughts from the group.

As a first step, I've been taking lots of photos. I'm also beginning to make a schematic drawing of the cockpit with the engine box and other cavities to get a better idea of the structure under the sole. A materials list is in there somewhere too. I figure I should make cardboard templates of all the pieces I will replace - as I go. This way I can get the slope/angle and size of pieces.

What else? Any cautionary tales, words of wisdom and success stories would be welcome.
 
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#2 ·
Just a suggestion but on smaller Boats under 20 for sure an OB will push it just fine. I am a big fan of IB motors even on small boats but I'm not a fan of Motors in the cockpit floor. The access is horrible to everything unless there are lots of removable covers inside. Can your floor be braced up (sisters) on the bracing below? I would consider using as storage with an OB motor you still need to clean it.

Now here's a Motor you can work on..

http://www.sailnet.com/forums/attachment.php?attachmentid=62065&stc=1&d=1450620165
 

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#4 · (Edited)
My boat, an O'day 35, had the cockpit sole core replaced by the PO. The old plywood core was cut out from the bottom (leaving the cockpit sole intact), and it was replaced with a sheet of 5/8" aluminum, which was bonded to the sole with a dense foam adhesive.


It has held up fine (and I consider it vastly superior to the original design) for over 11 years.
 
#5 ·
Interesting eherlihy.

Here's a few shots of what I'm facing.

Photo 1: an overhead shot of the forward starboard side of the cockpit. The sole is glassed plywood. I've started to mark lines of where the elements are below.

Photo 2: Shot of the cavity forward of the engine box.

Photo 3: Inside the engine box showing removed rotten wood w/ light from cavity in photo 2.

Photo 4: Moving aft in the engine box showing rotten wood

Photo 5: Farther aft showing saturated wood w/ seacock and vent.
 

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#8 ·
Some epoxies are designed to work on damp wood, what can't be replaced can be renewed. Not trying to divert your plans or discourage you. This IS a big job, find a good working spot some marinas are more accepting to people working on Boats. I will tell you its easier in the water, you might not think so at first but I would do the land side stuff then go afloat or make a nice set of temporary stairs. But this is probably a trailer boat at this size.
 
#10 ·
Well that changes everything. Boy I wish I could do that, I'm a cabinet and case work guy and have to drive back and forth to the boat to do things is the hardest part and its just 10 minutes away.

I have done a million detail items on my boat in the last year and have a million more on the list. The list is so long because I can do these things.
You need some tools, the new multi tool is nice for cutting things out and an inexpensive miter saw or at least a miter box will cut most of what you need. I like the idea of leaving the fiberglass in place and fixing the floor under that. The rest will come to you as you cut the bad stuff out. Some white oak would be best pressure treated pine deck wood is OK but I would dry it real good first.
 
#14 ·
More pics. Plywood core after removal. Plywood was still wet after sitting in heated and dry building for 4 months. Interesting in that even though wet the FG top and bottom layers did not have any cracks. The symptom was that the deck flexed when you leaned on the pedestal. Not a problem anymore. Second picture is a cutout piece used as a template for drilling holes in new solid glass are. Third picture was the first cut which is the deepest/
 

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#15 ·
Hi Brentonw! I would contact Marshall, and ask if they have the original wire schematic for the engine. If not ask on the Marshall site if some one could draw up a copy of their wiring for the same motor.
As for the rotten bulkheads in the engine compartment, you should be able to take care of that yourself. I would take your cell phone, and take pics, up under the deck, of your pic 2 & 3 to see how the panels are attached. Your 1st pic shows the panels only touching the under side of the deck. From your pics it looks like you, or previous owner had serious water problems before to cause that amount of damage. You just need to take measurements of the panels before you start, and pics. You can use a 4" angle3 grinder, to cut the tabbing, holding the ply in place. After you get it out grind down what is left. Mock up the new panels, even if you have to do them in sections, then coat them with penetrating epoxy, install, then glass back against hull, and deck where you can.
The other alternative, is to take out the old panels, then bound wood cleats to the under side, and back side areas where the panels would go, and make new 1 from star board, 5200, and screw them in place, to the cleats.
 
#16 ·
On removing a portion of the cockpit sole I'm finding the closed cavities under deck are filled with foam.

My main question is...

How necessary is the foam if I remove it and rebuild sections - and maybe not other sections? I don't really want to remove the entire sole.
Do I need to replace the removed foam?
Does the foam serve a required purpose?

My initial thought is to not replace the foam I take out and create air passages through all the areas I rebuild. This would facilitate drying.
 

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#19 ·
The foam could serve one of three purposes and possibly more than one at a time.

Insulation to reduce condensation.

Insulation to reduce transmitted engine noise.

Structural foam to increase strength.

The first two would be low density foam and the third would be high density foam similar to what is used to build foam filled rudders.

That's all I can think of right now and am sure others will chime in with better ideas.

Keep up the good work! Your making progress.

EDIT: Also could be for flotation but it looked like such a small area that I doubt it.


Sent from my iPad using Tapatalk
 
#20 ·
The foam could serve one of three purposes and possibly more than one at a time.

Insulation to reduce condensation.

Insulation to reduce transmitted engine noise.

Structural foam to increase strength.

The first two would be low density foam and the third would be high density foam similar to what is used to build foam filled rudders...

... Also could be for flotation but it looked like such a small area that I doubt it.
Makes perfect sense. In particular for noise reduction and structural support.

Up until now I haven't been thinking about the reduction (or increased) engine noise. Likely removing the foam will increase it. I'll need to figure out how to preserve reducing noise into the repaired sections.

(Attached is a detail of a piece of foam.)
 

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#22 ·
On many boats, one can simply build the cockpit well on a work bench and install it after it is finished. You can buy fiberglass sheet from a roll, leave the smooth side out. tack it to a framework and build up the other side until you have adequate thickness. You can even insulate it with foam sheet before installing it. Saves a lot of grinding.
 
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#24 ·
I'm familiar with the Sanderling because I strongly considered buying one and the Marshall factory is right here in Ma.

It's a great looking boat but I have to say I wasn't impressed with the construction choices. Perhaps the workmanship was fantastic (and older boats still had good looking gelcoat and certainly held their value) but the cockpit is just pure painted plywood. That was a big turnoff to me.

The newer boats are all fiberglass so that's good. They can retrofit the new fiberglass cockpit for only about $10k!

Anyways good luck. Do trying calling Marshall and see how much help they'll give you. Many older sanderlings have had this job done, either by marshall or their owners so if you look hard enough you should be able to find some help from someone who's done this.
 
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