Heresy in the Form of Titanium....

[ElBeethoven]

I hope I'm not burned at the stake for this, but has anyone tried or considered titanium hardware?

Before the traditionalists start building the pyre, the idea of a through-hull that is completely resistant to electrolysis or any other type of corrosion is MIGHTY appealing. The strength-weight ratio it offers ain't bad either. Plus, it's 40% stronger than stainless (depending on the exact grade) and 80% LIGHTER than bronze. And rather than shopping endlessly for pure 316 SS hose clamps, titanium offers a great alernative with prices that aren't prohibitive especially when you consider the expected life of the fitting. (A one-inch through hull is $60.) And titanium halyard shackles would save weight aloft which is ALWAYS a good thing.

In my defense, these are all "hidden" upgrades. It's not like I'd be putting kevlar, tri-radial sails on her.

Fair winds,

Jeremy

[ebb]

Below the waterline even a non-traditionalist might use a seacock on the thruhull. The problem would be finding a 316L seacock (bronze seacocks have too much zinc in the alloy IMCO) and a matching titanium thruhull. Above the waterline and on deck you could use 316 or any of the bronzes (silicone being the most common) for fastners.

Why not be the first to mix these metals in a submerged saltwater application and give us a report on any galvanic corrosion. In the mean time Marelon is a pretty good alternative.

There are Marelon folding mast climbing steps available now.

[Mike Goodwin]

I have pulled 30 year old Willcox/Crittenton silicone bronze seacocks that were in good working order after spending their life in Chesapeake Bay , Bermuda and the waters between . If you use bronze , just make sure it is a quality casting from someone like WC .

[ebb]

They made winches and stuff out of Marinium (an aluminum alloy) which is associated with the A/Cs, isn't it? Maybe not. Aluminum can be alloyed to be completely corrosion proof these days - and maybe we'll see an 'answer' to the titanium stuff coming on the market with tweaked Almag.

Wilcox-Critenden name is still around but it was bought by the Brit portapotti people. Why would they DO that? [Maybe because euros associate W-C with water closet, a separate small room containing only the head. Why don't Americans DO that?] W-C was around since yachting began and made just about anything, or everything out of bronze for sailboats. But it died 20 year ago.

We can assume the seacock AND the tailpiece were perfectly matched, with no other metals in the valve, and were alloyed, obviously, with long service in mind.

Hey Mike, how do you know the W-C seacocks were SILICON BRONZE?
And why did you have to pull them out?

Imagine what a titanium seacock would cost !!!

[Mike Goodwin]

Ebb,
Their catalog from the era listed them as SB ( the old boatbuilder I worked with saved all the old catalogs from the 30's and 40's, I wish I had them ) .
The boat was having some planking repaired and frames were being sistered or replaced , plus the old guy wanted everything stripped down and inspected , reinstalled and re-bedded . We also replaced half the keel bolts and a new transom . We stripped the mast , re-varnished and end for ended the rigging . We re-canvased the deck and made a new tiller and teak toe rail . Varnished the interior and installed a new watertank .

BTW,
Yesterday I was getting 5.6 knts with my Nissan 6hp 4 stroke ,on a very foul bottom ( haven't hauled in nearly 3 years) and that was at just over half throttle.

[Bill]

Yesterday I was getting 5.6 knts with my Nissan 6hp 4 stroke ,on a very foul bottom ( haven't hauled in nearly 3 years) and that was at just over half throttle.

Makes me want to trade in our low mileage 5hp 2-stroke Merc!!

[ElBeethoven]

Ebb, I'm a little down on my galvanic chemistry. Would bronze and titanium react? That is, is there an issue with a bronze seacock paired with a titanium thru-hull?

J.

[Bill]

Titanium is not subject to galvanic corrosion in seawater, however, it may accelerate the corrosion of the other member of the galvanic couple

Titanium also features excellent corrosion resistance, which stems from a thin oxide surface film which protects it from atmospheric and ocean conditions as well as a wide variety of chemicals.

Titanium is rather difficult to fabricate because of its susceptibility to oxygen, nitrogen, and hydrogen impurities which cause the titanium to become more brittle.

Because of its excellent corrosion resistance, titanium is also used for chemical processing, desalination, power generation equipment, valve and pump parts, marine hardware, and prosthetic devices.

Q: Can submersible vessel with copper/titanium interface be improved by plating?

A-1: CP titanium is the answer for sea water.

A-2: (from Russia) The dissimilar metal corrosion will take place - cupper will be suffered but the level of the phenomenon is dependent on the square rates. The best way is to made all of the items of titanium. If that is impossible I would recommend you to shield titanium by local oxidation procedure. The method is known and we use it many times including for a highly demandable apparatuses for sea water.

From the first note and answer A-2, I would assume that combining a titanium seacock with a bronze through hull is not advisable.

[ebb]

The metallurgists have a convenient voltage separation table called the Anodic Index in which metals are roughly listed in the same order as their 'nobility'. The closer two different metals are the less likely they will react.

Salt marine environments have the closest voltage separation: .I5v, ie different metals THAT close on the scale are less likely for one to become anodic. Gold and silver are close enough to leave one another alone. Titanium and silver are next to each other on the list. (Now it starts getting funny...) Monel and high nickel copper alloys - brasses and bronzes all fall somewhere in the same .15V protection zone, with silver and titanium.

However, seacocks these days are made from copper alloys with high levels of zinc in them, often way above the metalurgical safe level for an alloy not to self leach. Zinc is down there between aluminum and magnesium! We went into this in some earlier posts. Intuitively, I think adding another metal to the mix is asking for trouble. Do we know how inert titanium is? It may be just the voltage, just the cathode that sucks the zinc out of the valve. I've heard that T, is used for the thruhulls on aluminum boats and those two are at opposites ends of the galvanic table. But I don't know. Certainly would mean it don't wanna be a battery. If true.

But if it truly dosen't react with salt water, maybe it will work with a seacock, if you use a seacock you need nontapering matching threads on the thruhull. BUT, my friend, they do put titanium in the ANODIC index (but not graphite.) Let us know how it works out

(Just had a look at Bill's post above. The Russian is saying, like we know, that like belongs with like. It doesn't sound like he really knows what your application would be. If it were available, the very best hole in a boat would be a matched pair of thruhull and seacock in SILICON BRONZE. There just isn't a better alloy than that for seawater. IMCO, Marelon is next. IMHO, after that... there is nothing else! Nothing.)

[c_amos]

Titanium....


Titanium....


TITANIUM!!! Oh my!



Are not Bronze and Stainless expensive enough already!?!?