Ptarmigan 17 glued lapstrake yawl

[Steve TN 15]

Re: Ptarmigan 17 glued lapstrake yawl

Compliments on your shop!

It's a group thing similar to the "mens shed" setup and was originally the female ablutions block at the Catalina base that occupied the site during WW2. You can see the "Catalina" (Oughtred St Ayles Skiff) in some of the pics as well as an Oughtred Acorn, these were built here by members for members to row which happens twice a week.

[Steve TN 15]

Re: Ptarmigan 17 glued lapstrake yawl

While there is a lot of fiddly stuff going on with the hull some of the guys have moved onto other tasks like laminating cabin top beams. I've opted for a curved top rather than the three flat panel version as drawn. We are raising the cabin sides by 60mm to give a more pleasing arch without sacrificing head room.

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[Johan R]

Re: Ptarmigan 17 glued lapstrake yawl

I have heard of celery top and hoop pine, but not familiar with Australian white woods. Which species are you using for those laminated beams?

[Steve TN 15]

Re: Ptarmigan 17 glued lapstrake yawl

All the soft wood in this will be hoop pine, it's affordable, reasonably straight grained and clear of knots.

[Johan R]

Re: Ptarmigan 17 glued lapstrake yawl

I read Hoop Pine is classed as "non durable", just like Okume. Always seemed odd to me that a "marine grade" plywood is based on the quality of the veneers and the glue used, rather than the life span of the timber species used. $250 Auz for a 12mm sheet of hoop pine marine ply. Epoxy saves the day i suppose, even Baltic Birch plywood has been used in hull construction.

[WI-Tom]

Re: Ptarmigan 17 glued lapstrake yawl

I read Hoop Pine is classed as "non durable", just like Okume. Always seemed odd to me that a "marine grade" plywood is based on the quality of the veneers and the glue used, rather than the life span of the timber species used. $250 Auz for a 12mm sheet of hoop pine marine ply. Epoxy saves the day i suppose, even Baltic Birch plywood has been used in hull construction.

Yes. And radiata pine, too. For a small boat that will live on a trailer in a garage, built with epoxy techniques, I've found that these are perfectly practical choices. My brother's glued-lap 15' boat used baltic birch and is now 12 years old. My strip-planked boat used radiata, 6 years old. I don't think the "non-durable" label means as much with these kinds of boats as it would for a traditionally planked hull. Or for a boat that will live on a mooring, maybe.

Tom

[neil.henderson]

Re: Ptarmigan 17 glued lapstrake yawl

One of our group who isn't around any longer used to build his boats using several layers of 4mm brace play and that the worst timber I have ever used (I use it to make templates). But as far as he was concerned the timber was just a mould which was then encapsulated in fibreglass so the quality of the timber didn't matter. All of the boats he made are still floating and at least one lives permanently on a mooring.
I am making the mast step box in my CY using radiata pine - cut down from another friends garden (big garden). And I use hoop pine for all my keels, keelsons, etc.......

Regards Neil

[Steve TN 15]

Re: Ptarmigan 17 glued lapstrake yawl

[QUOTE=Johan R;6862166 $250 Auz for a 12mm sheet of hoop pine marine ply. [/QUOTE]

The hoop pine ply is beautiful to use, much finer grain than okume and a nice light colour and it's made in Australia so we know it complies with the standards BUT it's too expensive.

The interior of my Tammie Norrie (okume ply) is finished with Deks Olje 1 and it once had sea water laying in it for three days with no discolouration of the wood, meaning the oil prevented the water getting into the wood, that combined with epoxy on the exterior ensures a long life for the boat regardless of timbers used.

[Johan R]

Re: Ptarmigan 17 glued lapstrake yawl

... that combined with epoxy on the exterior ensures a long life for the boat regardless of timbers used.

Oh I agree. Look how many boats have been built with balsa core. A friends boat has Oregon Pine decks from 1947, so i wonder why a boat from the 1990s in the same yard is having its teak deck replaced. Coatings and care can make all the difference.

[Steve TN 15]

Re: Ptarmigan 17 glued lapstrake yawl

Finally the last 'glass is on the hull, now onto the delightful task of fairing and sanding, sanding, sanding...

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[Johan R]

Re: Ptarmigan 17 glued lapstrake yawl

Micro-spheres as the filler in the lands? Aluminium oxide paper works well.

[ADonald]

Re: Ptarmigan 17 glued lapstrake yawl

Steve, I can thoroughly recommend the “Arizona” sandpaper from Boatcraft Pacific. Lasts well and comes in 115 width for orbital sanders, sold by the metre. No connection, just impressed. Oh and it is free of the dreaded release agents so it won’t affect your epoxy.

[Steve TN 15]

Re: Ptarmigan 17 glued lapstrake yawl

Micro-spheres as the filler in the lands? Aluminium oxide paper works well.

The fillets in the lands are thickened epoxy for strength with epoxy filler over them to fair it all together. As for sand paper, see the next post

[Steve TN 15]

Re: Ptarmigan 17 glued lapstrake yawl

Steve, I can thoroughly recommend the “Arizona” sandpaper from Boatcraft Pacific. Lasts well and comes in 115 width for orbital sanders, sold by the metre. No connection, just impressed. Oh and it is free of the dreaded release agents so it won’t affect your epoxy.

Yes I'm using Bote Cote epoxy for the most part so I'm also using the sandpaper recommended by Drive Marine, the NSW affiliate of Boatcraft. It's "Wurth" and while it's a bit expensive it's worth every penny. Everyone is commenting on how well it removes material AND how long it lasts, you can sand for hours with a single piece and, as you said, no waxy release agents.

[Steve TN 15]

Re: Ptarmigan 17 glued lapstrake yawl

The first coat of sealing epoxy is on, still filling and fairing to be done before the next coats and then onto painting and righting

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