Professional Interior finishes: Epoxy/strip plank.

[rustybarge]

Hi All,

Just though i would post some photos of the sort of finishes a commercial custom boatyard can achieve with cedar strip planking.

Spirit only make custom made boats, the style is not to my taste, but take a look at the wood finish!
http://www.spirityachts.com/tablet/spirit-p40.html

a nice change from the plastic Tupperware mass production boats.

I think this method of hull construction is possible as a home build project, and not that expensive to make with cedar strip planking.





Unusual styling...!!!

 

[upchurchmr]

That is beautiful work.
I do have a concern about durability.
I recently made a "shadow box" for a neighbor out of cedar.
Before they were finished there were numerous dents in the cedar that had to be sanded out to get a good final product. That was with extreme care (for me) on a small project.

 

[philSweet]

Strip building is usually considered a time consuming way to get out a hull, but it can be cost effective if you have a supply of cheap labor, students, or you don't count your own time for much. But I wouldn't call that one strip built, anyway.

As done on that boat, it looks to be just carvel planked with edges glued (or perhaps cold molded). I don't see any random butt joints at all. I suspect that all the planks run full length. Also, I think it was built over a fancy mold, the outside skinned, the hull was pulled, and the inside finished before any frames were installed. Strip building tries to eliminate as much of that as possible by building over permanent frames and accepting the nuisance of finishing the interior with all the corners. It's appeal is its ability to produce sound hulls out of cheap and otherwise unsuitable material. Strip built should always be skinned inside and out because of the cheap wood and random butts used in the hull construction, and because of the desire to maximize panel size in order to minimize framing.

So in the case of the boat you pictured, premium materials and a highly labor intensive build, plus the need to produce a sophisticated mold for the construction. I think you could build a stripbuilt version of that hull cheaper than you could do the set up for the build shown. So I don't see the appeal for the home builder. Results like that require a very high level of professional expertise in business, management, and construction. Lovely crotch mahogany veneer work.

 

[rustybarge]

That is beautiful work.
I do have a concern about durability.
I recently made a "shadow box" for a neighbor out of cedar.
Before they were finished there were numerous dents in the cedar that had to be sanded out to get a good final product. That was with extreme care (for me) on a small project.

I have to agree, my only experience with cedar wood is shingles for a roof and they were definitely a soft wood.

Kids kicking the sides of the cabin would permanently damage the finish IMO....

 

[rustybarge]

Strip building is usually considered a time consuming way to get out a hull, but it can be cost effective if you have a supply of cheap labor, students, or you don't count your own time for much. But I wouldn't call that one strip built, anyway.

As done on that boat, it looks to be just carvel planked with edges glued (or perhaps cold molded). I don't see any random butt joints at all. I suspect that all the planks run full length. Also, I think it was built over a fancy mold, the outside skinned, the hull was pulled, and the inside finished before any frames were installed. Strip building tries to eliminate as much of that as possible by building over permanent frames and accepting the nuisance of finishing the interior with all the corners. It's appeal is its ability to produce sound hulls out of cheap and otherwise unsuitable material. Strip built should always be skinned inside and out because of the cheap wood and random butts used in the hull construction, and because of the desire to maximize panel size in order to minimize framing.

So in the case of the boat you pictured, premium materials and a highly labor intensive build, plus the need to produce a sophisticated mold for the construction. I think you could build a stripbuilt version of that hull cheaper than you could do the set up for the build shown. So I don't see the appeal for the home builder. Results like that require a very high level of professional expertise in business, management, and construction. Lovely crotch mahogany veneer work.

They don't say how the hull was made, not sure if this makes it easier to see......seems to be strip planking with long lengths?

 

[rustybarge]

Had another look on the website, no reference to construction techniques, only this photo:

 

[goodwilltoall]

That boat is very good looking. Spirit yachts is famous for their interior woodwork and heard one of their designs was in a 007 movie. Their sailboats are built using cold molded construction and you see the structural wood inside. Check out Langskipp boat for a similar look.

Look at the inside of a Norsea 27 vs Tartan 27 or any other fiberglass lined interior. Its a subjective matter discussing peoples preferences but I'll still venture to say over 90% would prefer the wood look. Both are about the same size. The dark wood looks very good but with smaller boats I would go for lighter colored woods. Hope to eventually add wood strips to my t27.

 

[upchurchmr]

With that quality of work I would not want to deliver the boat.
Just me. Anything I do seems to leave the house fairly quickly and I have nothing myself!

 

[rustybarge]

That boat is very good looking. Spirit yachts is famous for their interior woodwork and heard one of their designs was in a 007 movie. Their sailboats are built using cold molded construction and you see the structural wood inside. Check out Langskipp boat for a similar look.

Look at the inside of a Norsea 27 vs Tartan 27 or any other fiberglass lined interior. Its a subjective matter discussing peoples preferences but I'll still venture to say over 90% would prefer the wood look. Both are about the same size. The dark wood looks very good but with smaller boats I would go for lighter colored woods. Hope to eventually add wood strips to my t27.

The langskipp seems to be constructed in exactly the same way, just strip plank on laminated frames, but is there a layer of veneer on top like a cold moulded hull ?

http://www.langskip.com/Langskip.COM/Gallery/Pages/Valtyr_under_construction_2.html#12

 

[DCockey]

Had another look on the website, no reference to construction techniques, only this photo:

That's cold molding with the inner layer running longitudinally.

 

[DCockey]

I've never seen any "requirement" that a strip planked boat be built over permanent frames. I've seen many strip plank boats which were built over removable molds. Usually joints in the strips are scarf joints, not butt joints. Inside smoothing is much easier without frames in the way.

Francis Lee, aka Sliver, is a Bob Perry designed 62 foot sloop with a cedar strip planked hull which was discussed in the thread: http://www.boatdesign.net/forums/boat-design/francis-lee-sails-50335.html Sliver has cedar strip planking covered inside and out with a single layer of glass, and was built over temporary molds. Construction photos at https://www.flickr.com/photos/nwswb/sets/72157634502626642/

A strip planked hull could be built with short lengths of otherwise unsuitable wood with butt joints over permanent frames. But it doesn't have to be.

 

[rustybarge]

There's one for sale, have a look at the interiors, esp the beautiful cabin floors.
http://www.spirityachts.com/assets/jil_spirit_46_for_sale.pdf

Here's some more details of the construction techniques:

BROKERS COMMENTS
Impressive specification; optimised for racing and cruising. The Spirit 46 has all the answers, if you want an incredibly elegant hull form, very manageable sail plan (JIL can often be seen short tacking with just owner aboard!) and effortless fast cruising. Built 2003, (but lightly used) full carbon rig, an interior to cruise & race in total comfort; perfect sail wardrohe, very comprehensive electronics & navigation package.
CONSTRUCTION
Hull
- Brazilian cedar planking over male mould, 15 mm x 40 mm cover (speed strip), epoxy bonded and bronze fastened.
- Planking cross laminated with 2 x 3 mm Khaya veneers at 45 degrees.
- Hog, keel, stem and stern posts, horn timber, floors, beam shelf constructed from solid or laminated
straight grain Brazilian cedar.
- Lightening holes drilled without compromising strength.
- Hull is stiffened by fitting all the internal furniture in plywood bonded to the hull to form a
monocoque structure.
- Laminated ring frames form the chain plate mounts and mast partners and transmit the loads to hull
and keel bearing floors.
- All plywood used is Brynzeel brand, manufactured to Uoyds specs.
- Hull planking is sheathed with 6oo gsm bi-radial glass/ epoxy, faired with 2 layer epoxy fillers
and spray coated with Awlgrip paint system.
- Hull coated below the waterline with self polishing antifouling paint

 

[SukiSolo]

I've never seen any "requirement" that a strip planked boat be built over permanent frames. I've seen many strip plank boats which were built over removable molds. Usually joints in the strips are scarf joints, not butt joints. Inside smoothing is much easier without frames in the way.

Completely agree, strip planking and cold moulding are much easier over a removeable mould. The interior is so much cleaner to finish off. If you get crafty, the mould can even have slots to allow frames/bulkheads to be shaped into them to get a good fit when taken out. Another useful route is laminating into the moulded strip hull itself.

Likewise cold moulding, there is no definitive grain direction such as it must be at 90 degrees. Nothing wrong with quite a few different angles combined. Depends on lots of factors.

Very nice looking work, on this boat. Good to see the company is UK based.

 

[PAR]

That's strip planking, with an exterior veneer(s). You can work up the scantlings a bunch of ways. Frames permit you to use a lighter planking schedule, though I'd take it one step further and employ ring frames, instead of those laminated things. Saves a lot of labor. Strip planking really is just glued edge carvel, with narrow planks, in it's purest forms, sandwich core composite in it's more modern approach.