mast material?

[darlian]

newbie here from Indonesia..

me and my team is building 38m phinisi, right now we still making the centerline structure.
this boat will have two mast. the lower main mast will be abt 400mm diameter and 30m high from the keelson.
and the top mast 300mm and 15 m.
what will be the best material to make these masts, wood (red meranti or Oregone pine or?),galv steel pipe?alu?

thanks.

[alan white]

http://www.kastenmarine.com/phinisi_vs_klm.htm (what a phinisi looks like, it turns out).
I think most would use wood for low cost and aluminum for low maintainance.

[darlian]

thanks for the reply mr. White
we dont have marine grade alu in Indonesia so it has to be imported.. and i am also not familiar with alu mast construction..where can i learn about this?do you know any web site?

the owner wants this boat to have traditonal rig, as far as i know,many traditonal european sailing boats have mast made from steel or wood and modern rig usually have alu mast.....is it possible to mix traditional and modern rig? thanks in advance.

[alan white]

You can, like many people have done, use an aluminum mast on a wooden boat. I suggest you look up a mast fabricator and ask about the type of alloy that would be used.
Unlike a typical sailboat mast, a gaff rig needs no special extrusion of course. A simple round pipe will do, with an upper section that's either tapered or smaller diameter. Both steel and aluminum are simple to weld parts to, and modifications are very simple. Wood would require parts to be bolted on, although most of those can be shop-made from steel and galvanized.
Use any one of the three choices. Each has advantages and disadvantages. I like the idea of aluminum because it machines easily, especially the parts welded or attached to it, which can be machined on woodworking equipment. They can even be made by a good carpenter.
Steel has the advantage of retaining 100% of its strength when welded. Aluminum welds are never as strong as the base metal, and really good welds require a high level of expertise.
Any of the metals can be painted to look like wood if desired. I think you'll find that aluminum is the most expensive choice, but maybe the cheapest over time due to lower maintainance..

[BATAAN]

Wood is cheapest if you can go cut down the right kind of tree. It gets expensive if you glue a big one up. I learned as an apprentice 40 years ago to make a 60 foot mast from a 3' diameter log with a broadax and adze in about 50 hours, which was the expected industry standard. For your vessel a straight steel lower mast of pipe, stepped through to the keel, can double as the engine exhaust or a ventilator if you wish. The topmast should be wood, doug fir or spruce, something springy and light, and rigged in the trad way to house or come down on deck through the cap and crosstrees. If you go to sea much you will lose the occasional topmast to leeward through carrying sail so design accordingly. See Pete Culler for some drawings and details. Light is always better, and the very thin and light Chesapeake methods of housing their topmasts on the Pungys and smaller schooners is worth close study. The rig design must complement and balance the hull design or any good boat can turn into a dangerous dog.

[Stumble]

Darlian,

I know it is a little nuts, but you may way to see if there are any old maxi rigs available, particularly in California. The 30m rig would work out to about the same height we had on an Andrews 70' I worked on, and when the boat was totled we wound up selling the carbon fiber rig for almost nothing just to get it out of the yard.

Beyond that, I tend to lean against wood masts, particularly of this size for a couple of reasons...
1) they weight involved in substantial.
2) Poor craftsmanship of a rig this tall could result in the whole mass falling onto the deck. Since I assume that the mast would have to be a laminate of some type I would only use a very skilled carpenter, which would likely offset any material savings cost.
3) Aluminium is almost maintenance free, and not having to worry about inspecting work done that high up on a wooden mast would be worth something to me as well.


Note: I come from a racing background and am not as familure with wooden construction as a lot of people here, so take my advice here with a grain of salt.

[Brent Swain]

For my designs over 36 feet , most owners go for steel masts. They come out slightly lighter than wood box sections and tangs are easily attached by welding, making the lightest and most structurally reliable rig possible. They are also very inexpensive, and you can do the work yourself. They cost a fraction the price of aluminium , and are much cheaper than many wood masts.

[BATAAN]

For a 38 m boat with gaff rig, I agree that steel is best.

[darlian]

thanks for the reply guys....

i think my first choice will be steel for the lower mast and wood for the top mast, there will be 8 crews onboard that can inspect and paint the mast regularly..

i think for 16 inch dia mast, steel is lighter than wood

[darlian]

the owner of this phinisi boat have decided and agreed to use steel pipe for lower masts and wood (local dark red meranti wood) for the upper masts and booms.

can anyone suggest me what kind of standard steel pipe should i use?
ASTM, AWWA, API 5L Spec, BS, JIS, DIN?

thanks in advance!

[Perm Stress]

Originally Posted by darlian

the owner of this phinisi boat have decided and agreed to use steel pipe for lower masts and wood (local dark red meranti wood) for the upper masts and booms.

can anyone suggest me what kind of standard steel pipe should i use?
ASTM, AWWA, API 5L Spec, BS, JIS, DIN?

thanks in advance!

Any standard You could get locally and which contain the tube size You want.

More important is RELIABLE QUALITY of production you are buying.
high strength (H36 ) steel is much preferrable, because steel is very stiff material and any transverse loads (like from the gaff, or a result of slight mast sag to leeward when sailing) easily translate to bending moments in the tube.

Quality certificate, acceptable to well recognized classification society (eg, Lloyd, Germ. Lloyd, Det Norske Veritas) could not be overvalued - it will ensure you are getting REAL THING, not waste water pipe or something.

Certified welders will ensure (to a degree) they do a REAL JOB (with 100% X-ray control of all welds).

I speak from experience -masts to my design are stepped today on 34m schooner. Germanisher Lloyd survey was a great help in quality of final product!

Good luck!

Originally Posted by Brent Swain

For my designs over 36 feet , most owners go for steel masts. .

That does´nt mean much Brent. May I quote you?:

Originally Posted by Brent Swain

I've never designed anything over 40 feet.

That steel wood combination seems to be a sensible compromise. At least where Al. is´nt that easy to get.

Regards
Richard

[dskira]

Originally Posted by Stumble

Darlian,

I know it is a little nuts, but you may way to see if there are any old maxi rigs available, particularly in California. The 30m rig would work out to about the same height we had on an Andrews 70' I worked on, and when the boat was totled we wound up selling the carbon fiber rig for almost nothing just to get it out of the yard.

Beyond that, I tend to lean against wood masts, particularly of this size for a couple of reasons...
1) they weight involved in substantial.
2) Poor craftsmanship of a rig this tall could result in the whole mass falling onto the deck. Since I assume that the mast would have to be a laminate of some type I would only use a very skilled carpenter, which would likely offset any material savings cost.
3) Aluminium is almost maintenance free, and not having to worry about inspecting work done that high up on a wooden mast would be worth something to me as well.


Note: I come from a racing background and am not as familure with wooden construction as a lot of people here, so take my advice here with a grain of salt.

If the gaff and boom as a throat they will eat the alu mast in no time.
Wood is the most easier for all the attachment and the slinging of the shrouds.
And the alu, will not go well with this type of vessel.
Stumble, don't sue me
Daniel

[Stumble]

Originally Posted by dskira

Stumble, don't sue me
Daniel

The lawsuit is already filed... paperwork is in the mail.

[dskira]

Gasp