Replacing Traditional Wood Masts with Alloy

[chris95040]

Originally Posted by Terra Nova

Replacing with an aluminum mast will almost certainly provide a measurable and noticeable performance improvement, reduce maintenance, and add value to your boat.

+1. I have sitka spruce hollow-box masts on my yawl. The marina broke my spreader putting the mast away this year, and i had given that spreader a reasonable (guess not) inspection last year and thought it was fine. Turns out it was hard on the outside, sponge on the inside. Sobering, so I'm making up a new aluminum main mast this year.

The process: hired Brion Toss to calculate section stiffness required, inout to this process is stuff like the boats righting moment, sail plan, spreader configuration, and in my case, details of the wood construction plus details of an aluminum section the designer specified years ago. This was cheap and made everything a lot less scary having an expert running the numbers.

Then find a section that provides the x and y stiffness required and measure where every damned thing is on your current mast and communicate it to the spar provider.

For me Klacko spars came in at the most cost effective, they are also nice folks to work with.

Regarding weight, most folks say an aluminum mast will come in at about 75% the weight of a comparable spruce mast. This seems to be my experience: When i run the numbers, my spruce section should weigh about 350lbs, the aluminum section, 250lbs. That should have a positive benefit of stiffening up the boat, but the roll will not be as slow anymore.

[roverhi]

Might think about Carbon Fiber mast from NZ. No rot or corrosion issues with careful addition of hardware. Shipping from the Land of the Long White Cloud should be dirt cheap. Carbon fiber isn't inexpensive but the Kiwi's are doing some nice work at prices close to what Aluminum sticks are in the States.

Wood masts on orient built boats are probably fir not spruce. That would make them considerably heavier than Chris95040's estimate for spruce.

[Stumble]

I was gong to suggest carbon fiber as well. prices have come down a lot in recent years, and because shipping costs are stable regardless of the material the total cost difference may not be substantial. At least at this point I would explore the option.

[Schooner Chandlery]

If the fastener holes you have were/are elongated, it is often because of too much or uneven loading. We had this happen with a mast band on our foremast that had been asymmetrically loaded by a previous owner keeping too-tight rigging (in our case a staysail stay load). Older boats like mine don't employ the same high rig tension as post-60's era boats so in our case the particular mast band was never designed for the load a previous owner had subjected it to--the same owner, racing the boat, also broke the mast step in compression with the over-tensioned rig.

In your case it may indicate uneven loading. Don't just automatically add more fasteners as your fix to the loading, and don't automatically add metal plates and tangs. Consider adding a shoulder of wood to the mast to take the load of the problem rigging and asymmetrically loaded collars. If you use a plate, it should be cut into the mast 1/32" to 3/16" depending on the loading and plate. Just bolting a tang or plate onto your mast may LOOK the same but it doesn't perform the same way at all. If you keep the mast and repair it, feel free to PM or open the discussion here of how to do a wood shoulder/cleat to support a load on the wood mast. If the problem for you was with the collared spreaders, it is likely that the rig tension, over a period of time, have been wrong for the boat and created the problem. The spreaders should push against the mast in a compression load with no upward or downward loading that would create that kind of elongation.

It is no big deal to scarf even quite large repairs in a wood mast. You likely don't require very large sections of wood to do this (even 12:1 scarfs) so you can have exactly the correct wood even MAILED to you from another location if you needed to. You are in the Philippines, right? The PI has good logistics for getting things in-and-out of country.

About paint vs varnish--our 84 yr old mast was painted for most of its life. We have many varnished surfaces on the boat and I love the look of varnish but we decided to keep the masts painted for the good of the masts. We use a traditional oil-based paint that is nothing like a modern 2 part marine coating. We worry that if there is a crack in the paint and water intrudes, modern coatings hold the moisture in against the wood rather than letting it dry and rot will then happen. We inspect the masts regularly of course.

Built up wood spars like your boat came with are beautiful, strong, infinitely repairable, and the reason I see people replacing them them with aluminum alloy is because they just don't know what a gem they've got. There are so few wood spars out there, properly maintained, that the majority of modern boat owners no longer understand the benefits of wood spars. When someone hears "rot" they run like Chicken Little rather than just dealing with it because it can be no big deal at all.

Good luck with your inspection and repairs (if needed) of your spars.
Brenda

[reed1v]

Originally Posted by Terra Nova

Replacing with an aluminum mast will almost certainly provide a measurable and noticeable performance improvement, reduce maintenance, and add value to your boat.

One of which will be a more tender boat. It will heal quicker and right itself quicker. You may or may not like the quicker motion to the boat.

Had a Cheoy Lee with spruce masts that were covered in fiberglass, epoxy paint and then poly paint. Lasted years, still doing service 40 years later. Will last as long as aluminium will as long as you take care of them. Plus aluminium corrodes.

[chris95040]

Originally Posted by reed1v

One of which will be a more tender boat. It will heal quicker and right itself quicker. You may or may not like the quicker motion to the boat.

Depends on your definition of tender- with a lighter mast your boats level of heel will decrease, which some call stiffer. You are right that the motion will be quicker though.

[chris95040]

Originally Posted by Schooner Chandlery

.

It is no big deal to scarf even quite large repairs in a wood mast. You likely don't require very large sections of wood to do this (even 12:1 scarfs) so you can have exactly the correct wood even MAILED to you from another location if you needed to. You are in the Philippines, right? The PI has good logistics for getting things in-and-out of country.


Built up wood spars like your boat came with are beautiful, strong, infinitely repairable, and the reason I see people replacing them them with aluminum alloy is because they just don't know what a gem they've got. There are so few wood spars out there, properly maintained, that the majority of modern boat owners no longer understand the benefits of wood spars. When someone hears "rot" they run like Chicken Little rather than just dealing with it because it can be no big deal at all.

Good luck with your inspection and repairs (if needed) of your spars.
Brenda

Theres definitely truth to all that... I'm keeping mine, and some year will split and reglue all the failing seams, make any repairs, strip and start over with the varnish, etc.

But i'm looking forward to the aluminum not /needing/ to be repaired, or scuffed and varnished (or painted, but if painted wtf is the point?) or really, anything! And the boat will stand up straighter.

[Djarraluda]

Delaney refers to the alloy sections available. Reference to the "sharp" corners will often indicate the typical aluminium sections, but these are also the land based alloys. Marine grades of aluminium, in the typical extrusions are normally with rounded corners.
It may be possible to get these reversed, so I would not offer any guarantee, but as a general rule of thumb - sharp cornered aluminium sections do not belong near salt water!
Roger

[Nicholson58]

Originally Posted by Pelagic

My 33 year old traditional schooner rigged Spruce Masts are coming off in early January for inspection and new electronics.

While all the stainless Rigging and Sails have been replaced and are still like new....The only thing I am considering is switching to Alloy Poles, before we get back into full time cruising.

I am not expecting any structural issues... just sloppy issues from showing its age and changes over the years

My thought is.... that with changing all of my mast electronics and possible weight savings aloft, now might be the time to replace while I am finishing the last of my refit.

You can see it is a simple box structure which could lend itself to internal PIPE in each of the 4 corners with flat plate on 4 sides.

Alternately, I could cost an Extrusion to be shipped to the Philippines, but I am guessing this would be expensive!!

Another plus of making them in Subic is we can reuse the Stainless Tangs and Hardware the works so well.

I am thinking that building side by side with the old old mast and hardware as a mock-up, should minimize any positioning mistakes, so that I can reuse all my standing rigging and furling system.

Thanks from any thoughts or advise from some of our Alloy structural gurus on this.

My opinion is that if the existing spars are in good ape I would stick with them. The photo shows the rig to be relatively short so there is not so much to be gained by reducing weight aloft. If you really are set on going Aluminum then locate spars and location and plan your cruising to meet the spars. There is also a high possibility you can locate used spars - same plan.


Note on current spars - I met with a yard mate today who was examining a crack in his mast at the toping lift block. Incredibly thin extrusion begged failure. A stick is not a stick is not a stick. I like the peace of mind of brutally strong stuff.

[reed1v]

Gotta laugh when the kid said aluminum masts would be maintenance free. Good luck. You will need isolating plates on all metal mast fittings otherwise your mast will corrode to dust within a year. The foot of the mast will corrode regardless what you do since salt will be in contact with the base 24/7. And do not forget the slapping noise that will drive others to the point of sinking your boat unless you strap your halyards off.

[chris95040]

Originally Posted by reed1v

Gotta laugh when the kid said aluminum masts would be maintenance free. Good luck. You will need isolating plates on all metal mast fittings otherwise your mast will corrode to dust within a year. The foot of the mast will corrode regardless what you do since salt will be in contact with the base 24/7. And do not forget the slapping noise that will drive others to the point of sinking your boat unless you strap your halyards off.

Nonsense.

[Delancey]

Originally Posted by Djarraluda

Delaney refers to the alloy sections available. Reference to the "sharp" corners will often indicate the typical aluminium sections, but these are also the land based alloys. Marine grades of aluminium, in the typical extrusions are normally with rounded corners.
It may be possible to get these reversed, so I would not offer any guarantee, but as a general rule of thumb - sharp cornered aluminium sections do not belong near salt water!
Roger

Marine grades of aluminum? You mean something in a 5000 series? No one extrudes mast sections in 5000 series. Better corrosion resistance but lacks tensile strength. People just anodize instead.

The "architectural" extrusions I refered to are available in the same 6000 series used by every spar maker. Selden, Hall, Kenyon, Metal Mast, Sparcraft, Isomat, etc.

The OP wants an affordable alternative to his wooden box section masts. He has roller furling units for his mainsails. He wants to use these. He doesn't want to go out and buy a new set of sails. He doesn't want carbon. He doesn't want a typical aluminum mast extrusions.

Hopefully he will scrap some paint and determine there is nothing wrong with his wooden spars.

[Terra Nova]

Originally Posted by reed1v

Gotta laugh when the kid said aluminum masts would be maintenance free. Good luck. You will need isolating plates on all metal mast fittings otherwise your mast will corrode to dust within a year. The foot of the mast will corrode regardless what you do since salt will be in contact with the base 24/7. And do not forget the slapping noise that will drive others to the point of sinking your boat unless you strap your halyards off.

Nonsense.

[ingrid75]

Replace wooden masts with alloy? Sir, you are a Phillistine.

[Jim Cate]

Originally Posted by reed1v

Gotta laugh when the kid said aluminum masts would be maintenance free. Good luck. You will need isolating plates on all metal mast fittings otherwise your mast will corrode to dust within a year. The foot of the mast will corrode regardless what you do since salt will be in contact with the base 24/7. And do not forget the slapping noise that will drive others to the point of sinking your boat unless you strap your halyards off.

Geeze, Reed, be serious!

Had our then 23 year old alloy spar out for a check two years ago.

No corrosion under the step... none.

Small paint bubbles at a couple of s/s fasteners... all of which came out without issue.

The paint was chalky, but polished up fairly well.

The only fault discovered was small cracks developing in the spreader base roots (swept back spreaders which put a lot of load on the bases). Our rigger welded them up and added a bit of reinforcement to the front edge of the bases. Less than an hour's work... after 23 years of long distance sailing, including both the Arctic and Southern oceans.

OH... one other thing found: the manufacturer of the spar had installed the backing plates for the T-ball terminals upside down! Must have been the apprentice sent to do that... but there were no failures involved.

So, reed, I gotta disagree with your careful analysis of the aluminium mast issue.

But I still would have a good look at the timber spars on Pelagic's schooner before replacing them with anything!

Jim