84 ft yacht

[BrettM]

Hi all,

I promised some of you pics of a project I am working on. Have a look and feel free to ask me questions. I will try to answer as much as I can but don't expect me to answer very specific questions - Some answers I need to hold close....

These pics are several months old now. The 3d model is a basic model only. The real thing is much more curvaceous.

Length (hull) 25.6m
Beam 6.60 m
Draft 2.4 m

Now ask me some questions or make comments.

[BrettM]

Ok, maybe I scared a few of you off. When I said don't expect me to answer very specific questions I meant things like "What is the exact hull laminate" I would however, be more than happy to discuss things in a general nature. Design, Software, construction, etc etc etc. It's all here. Just ask.

Brett

[Tad]

Brett;

Not scared, just slow. More info on the boat please; weight, power, SA, ballast, tankage, equipment.

The things that are interesting to me about these large wooden sailing yachts is the point loads and how they are handled. Especially the rudder/steering gear, chainplates, ballast attachment, sheet loads, mast steps, etc. Does the boat have a centerboard? Are you using "potted" fastenings and/or load pins? Any "zebrawood"? (uni glass in wood laminations to provide cross-grain structure)


All the best, and thanks, Tad

[BrettM]

Tad,
I don't think of this project as a timber yacht because it is essentially composite. Whilst a significant amount of timber has been used in the primary structure and planking, all the frames are foam/db/uni laminates and the deck pilot house are glass/balsa sandwhich. No Zebrawood in this boat. Had considered it initially when the frames were to be laminated.

No centreboard - gentlemen don't go to windward.

Tankage - An relative large fuel load is carried to facilitate long distance cruising. The majority is contained in two wing tanks located in the engine room. The advantage of the wing tanks is that in a half full condition approximately 2.5 tonnes of fuel can be pumped to the windward side. Primary power is a 350 hp diesel - conventional shaft drive with a feathering prop.

Keel is steel with internal ballast. Keel is more than 10 metres in length (33 ft) and is a boat in itself. Flat base for ease of construction and a good spot to sit the hull on. Ballast subject to the final displacement. (Boat to be floated as part of the process)

Keep em coming.
Brett

[BrettM]

Thought that this might have developed a stronger response. Guess that not many people here are interested in design and construction.....

(Scratches head, walks away to find christmas beer)

[jprev]

Maybe they're all dumbfounded by the genius of the design!

I personally think it rocks, even though I don't give a whit about a wind powered boat....

Did you find a extra beer?

[Chris Krumm]

Nice boat, Brett.

If I remember from your posts on another thread in the Materials forum, you were strip planking the hull on male moulds and glassing exterior and interior with triaxial glass.

Care to comment on the viability of planking a boat this size in female moulds? Also, what was your method for bogging and fairing the hull interior and exterior? Must be an onerous task no matter how you approach it...bet you drank more than one Christmas beer in the process.

Chris

[BrettM]

Hi Chris,

This particular boat was built upside down on its bulkheads and temporary cnc cut mdf frames then glassed on the ouside and rough faired. I say rough faired because the epoxy needs time/postcuring before final fairing. Boat was then turned over with the fraomes in place and then laminated again in sections with the temporay frames removed as construction went on.

For the record the only interior surface that was faired is the engine room. No need for the rest as it is all covered up.

Please keep in mind that I am not the builder - just a designer/NA. but I believe that doing this yacht in the female sense with strip plank construction would be difficult. It would also be far easier to wrap planks around a jig than pull them into it. Access to the hull from the outside with scaffolds would also be easier whilst the hull is upside down.

On the other hand if this were a sandwich boat with a foam/balsa etc core then a temporary female mould could be the go. I believe mirabella was built in a temporary female mould. Of course fairing would be a little simpler in this case as the glass overlaps are then on the inside. I do not know if mirrabella's hull was refinnished after the mould was removed. I would suspect that it probably was completed with 2 pak.




Brett

[Bill the Cat]

Brett

Nothing personal, but that project is so beyond even my wildest boat dreams - that I'm overwhelmed by the scope of it.

1. What's the Captain's intended usage?

2. How long to get to this point?

3. What's the hull composition - what are the layers?

4. Can the owners adopt me?

Dave

[BrettM]

Dave,
Nothing personal either. I am proud and amazed that I am tied so deeply into such a project at this stage of my career.

Intended Usage is long distance cruising and charter work. Not talking backpackers though - yet.

I've been involved in this project from the beginning which is about 2.5 years at this point. Expected launch date is later this year. Currently the boat is sitting with its engines and a significant amount of internal timber work well on its way. Internal finnish is mostly cherry wood with some australian timbers else where. Pilothouse is built and being fitted beside the hull. It will not be fitted until the boat is transported to a location nearer to the water. (It won't fit under powerlines to get there)

Hull Composition - Kauri strip planked core with Triaxial Skins. All resin thoughout is epoxy. (Exact laminate is tied to commercial confidence). Approximate completed hull thickness is 40mm. Probably could have increased this thickness somewhat and reduced some of the hull framing but timber availability was the driving force behind it.

Can the owners adopt you? I can ask if you likeand get you put on the list.

Brett