60ft oak on oak restoration project

[wolfaroo]

Hi, I hope you're all well & having fun.

It's been a little while since I posted, progress is being made, albeit a little slower than hoped in terms of the deck. This project is not for the impatient! A couple of developments led to a decision to tackle the deck whilst afloat, which meant moving her from the original mooring to somewhere more suitable/accessible. Not straight forward though of course, resulting in a change in the order of planned works.

The new priority became the engine/running gear. It took a few weeks just to get unrestricted access to the engine (previous owner had blocked it in and built various structures around it, including a wet room complete with a full size bath) and once there, I drained the sump to discover it contained... >27 litres of water. The raw water seacock had been left open, the makeshift swan neck had dropped several inches and with the bilges full of water the boat sat an inch or two lower, the swan neck dipped just below the now raised waterline and water siphoned into the exhaust manifold, through the valve guides into the sump and from there around the entire engine lubrication system, displacing the oil into the bilge. No-one knows for certain when it was last run, but it was likely full of water for at least 3 years!

Luckily though, the engine is a Gardner and the water wasn’t the salty type. It took a few weeks, several oil & filter changes, rewiring and servicing of the starter motor, repairs to the governor, flushing/bleeding of cooling & fuel systems, some new hoses, lots of turning over manually and incredibly, with a puff of smoke, she fired back into life! As the old advert went "any engine will get you to sea, but a Gardner will always get you home". Quite remarkable really. There is a video of her running for the first time here: https://youtu.be/sRX0f10Ojx0

In late June the boat was moved up the tidal estuary under her own steam to a town Quay. It took two sets of spring tides to get her fully alongside and she is now comfortably in the mud (‘London caulking’), and I can now, finally, refocus on the deck.

Per advice on this thread and elsewhere, I’ve opted for a ply (BS1088) subdeck sheathed with cloth/epoxy. I’ll then be gluing an additional layer of ply atop the sealed subdeck, with shallow grooves routed & filled with black seam compound to give the appearance of planking, as a sacrificial wooden deck to give a more traditional look/feel.

So, to the questions! (The answers I’m currently leaning towards are in brackets after each question, but I’m open to other recommendations and very happy to hear your experiences/opinions!).

1> How would you recommend I fix the ply subdeck to the oak deck beams? (screws + marine sealant)
2> What fixings and/or adhesive/sealant would you recommend I use between deck & beams? (silicon bronze full body wood screws + sikaflex 291 or similar)
3> Should I treat the beam top surfaces prior and if so, with what? (metallic wood primer or red lead primer)
4> Should I treat/paint the underside of the deck prior to laying and if so, with what? (metallic primer)
5> What type of cloth? (2 x layers 300gsm woven roving)
6> What adhesive should I use to secure the sacrificial deck atop the subdeck? (epoxy, although it’s also been recommended I use a more flexible sealant such as sikaflex)

Finally, I promised some photos and although I’m yet to upload them (hopefully next week sometime) there is one attached of her in the mud a couple of tides prior to reaching the quay wall. Others to follow in due course and I will post more often, if anyone is interested.

Cheers and fair winds.

[Pete7]

If you have used epoxy on top of the ply deck then use the same again underneath and particularly around the edges before you seal it down.

Not sure what advantage you gain from using Sikaflex between the ply and the beams. The deck is going to be solid and dry the beams presumably exposed and may swell and shrink as the temperature and water content changes, or have then been heavily painted over the years?

The volume of Sikaflex you are proposing for the sacrificial deck is going to cost a fortune, find something cheaper from Screwfix / tool station etc. These will be cheaper:

Trade Sealants Ltd marinemastics.com

[wolfaroo]

Thanks for the link Pete, anything a little easier on the wallet is welcome!

Beams have been heavily painted but will be taken back to wood & treated for the most part.

As promised, here is a link to more photos, viewing not recommended for the faint of heart though https://www.flickr.com/photos/142945623@N08/albums

I've started ripping the rotten deck up now and will add some updated photos within the next couple of weeks.

Further comments/recommendations/opinions re the below are invited/encouraged

1> How would you recommend I fix the ply subdeck to the oak deck beams? (screws + marine sealant)
2> What fixings and/or adhesive/sealant would you recommend I use between deck & beams? (silicon bronze full body wood screws + sikaflex 291 or similar)
3> Should I treat the beam top surfaces prior and if so, with what? (metallic wood primer or red lead primer)
4> Should I treat/paint the underside of the deck prior to laying and if so, with what? (metallic primer)
5> What type of cloth? (2 x layers 300gsm woven roving)
6> What adhesive should I use to secure the sacrificial deck atop the subdeck? (epoxy, although it’s also been recommended I use a more flexible sealant such as sikaflex)

[Schooner Chandlery]

Hi Wolfaroo, I enjoy seeing your project boat and wish you well in completing the project. My husband and I re-did a smaller boat (54' on deck) in a complete rebuild 2007-2009 timeframe. You can see some boat pics here and some projects in our older blog posts here.

We used a splined Alaskan Yellow Cedar structural overhead 3/4" thick and then two 3/4" layers of BS1088 atop the deck beams. Very stiff which is great for a sailboat.

Our oak deckbeams had enough rot in them (from iron fasteners the white oak was ruined) that we decided to re-do all the deckbeams. This link has a lot of deck beam pics.

The overhead going down here

The last look at the overhead before putting on subdeck here.

The BS 1088 ply can be seen here

Ah, a better pic of the BS1088 ply here

We used an elastomeric roofing system (Metacrylic) to waterproof the deck and that could have been the final finish but we added canvas for grippyness and traditional look. We could always epoxy down a thin (teak decking systems type 3/8" teak) over the Metacrylic if we wanted that yachty look but it doesn't really appeal to us. The Metacrylic can be seen in that pic above showing the 1088 ply. Before painting, the canvas stapled to the edges can be seen in this pic.



1> How would you recommend I fix the ply subdeck to the oak deck beams? (screws + marine sealant)

Skip the word "marine" We used something called PL Premium which is a construction adhesive. There are a couple different versions to this adhesive but it was the waterproof one that we used. I see with google that the company is now owned by Locktite, so not sure if you can speak with their engineering staff (as I did) anymore.

We used bronze screws from the AYC overhead into the deck beams. We then used a Raptor nailgun with plastic Raptor nails (no corrosion) to nail the first layer of BS1088 to the AYC and of course, lots of PL Premium construction adhesive. Then the next layer of plywood laid perpendicular to the first, plenty of PL Premium between the two and plastic nails holding it together.

On top of that, the waterproof and flexible elastomeric and on top of that the anti-skid of traditional painted canvas.

2> What fixings and/or adhesive/sealant would you recommend I use between deck & beams? (silicon bronze full body wood screws + sikaflex 291 or similar)

Described above

3> Should I treat the beam top surfaces prior and if so, with what? (metallic wood primer or red lead primer)

We use white lead paste stirred into a white primer or red lead primer on mating surfaces, yes. However, the deck beams were sanded of all primer so they could be adhered nicely to the AYC overhead.

4> Should I treat/paint the underside of the deck prior to laying and if so, with what? (metallic primer)

If painted, yes that is easiest but you have to not paint the mating surfaces where the deck beams are if you're going to be using any adhesive. Othewise you're just gluing paint to paint.


5> What type of cloth? (2 x layers 300gsm woven roving)

I would not use epoxy in this application. As stated, we used a paint on elastomeric and it had a polyester scrim that goes down first. The end result is a sold sheet of rubber that won't crack (as resins can) or leak.

If you do go with a epoxy, choose one that is more flexible than WestSystem and try to use something like Dynel (polyester) rather than glass. This is not structrual for you, it is simply water proofing. Your structure is in the ply.

6> What adhesive should I use to secure the sacrificial deck atop the subdeck? (epoxy, although it’s also been recommended I use a more flexible sealant such as sikaflex)

As mentioned, we used PL Premium construction adhesive as the best product for gluing.

I think it's kind of hinky to do as you plan with the grooved wood deck--If I were you I'd just put down a straight laid (but thin essentially a veneer) wood deck of white oak, AYC, fir, or another material you can PAINT for a workboat deck. If you do a veneer type wood deck, you may be stuck using an epoxy adhesive with it and you may be stuck using fasteners that will penetrate your plywood. That is largely why I wouldn't do it.

I typically don't like it when people veer away from traditional methods and materials for wood boats. Especially when using layers of resin/epoxy to prevent water ingress to hull and/or deck. Think carefully about it. Traditional methods work well, are repairable, and maintainable.

Our deck, canvas painted completed looks like this



All just my opinions. Enjoy your project! If you should need (US based) materials please feel free to contact me via the Schooner Chandlery or PM. We have a seller in the Chandlery who has great pricing on the larger diameter silicon bronze screws and bolts for example and he will ship abroad just charging actual shipping. After we used the Metacrylic successfully on our boat for some years, we've contacted the company to distribute the product. We're not advertising it (yet) because they don't offer the smaller quantities that most boats would need and we're working with them on that as well as a few other matters. We just purchased a large quantity ourselves and then gave the left-overs to a fellow who was needing some roofing materials for his house and wanted to use Metacrylic.

[Schooner Chandlery]

PS--the two BS1088 plywood layers added up to 3/4" total. Not 3/4" each. Our total deck thickness was 1-1/2" thick.

We replaced a teak deck, straight laid 1-3/8" thick as built back in 1931.

[Roebear]

I have a 1932 motorsailer that is planked in just that method: 3/8 in. planks diagonally and glue and canvas, then longitudinal planking 3/8 in. thick, all of Port Orford cedar.
best success!