Titanium Chain Plates and Mast Fittings

[F10]

I am in the process of replacing all my chain plates (and bolts) and my mast hardware with Grade 5 Titanium. Have all the parts in hand and will be installing during next few weeks. Boat is located in harsh tropical environment thus the choice for the Ti Gr5.

Does anyone have any real life experience with Ti that they can share any things to look out for or avoid? I am replacing the mast tang bolts with Gr 5 Ti and have heard shear strength for Ti is less than 316 ss however that is not what I find on publish literature.

[Jim Cate]

You might try PM to CF member "Stumble". He has experience with Ti applications.

Jim

[F10]

Originally Posted by Jim Cate

You might try PM to CF member "Stumble". He has experience with Ti applications.

Jim

Thanks, I'll give it a try.

[Cheechako]

Titanium threads can gall quite easily, so just be careful about that. realistically, common bolt threads are usually loose enough fit that it wont likely be a problem. Mast thru bolts for tangs are usually pretty big.. not sure you'd ever shear that off? But Ti can be crack prone if the manufacturing process is not controlled well. so these are probably 6AL4V ti I guess? What do those cost now days?

[Lojanica]

I made and installed titanium chainplates. I used titanium bolts. I used thread lubricant liberally during install to avoid galling and lock washers. Copper based anti-seize grease from Loc-Tite C5A for example.

Titanium as the more noble metal will scavenge electrons from aluminum so on the mast you should protect the aluminum to avoid electrolysis. I found thin plastic sheet and tefgel to be helpful in isolating the titanium from the aluminum. Just keep the metals isolated by either making a plastic sleeve or shrink wrapping the titanium where it would normally touch the less noble metals.

Titanium is difficult to work with. You'll need to minimize any refitting if possible as the stuff will eat your standard tools at a rapid clip.

[F10]

Originally Posted by Cheechako

Titanium threads can gall quite easily, so just be careful about that. realistically, common bolt threads are usually loose enough fit that it wont likely be a problem. Mast thru bolts for tangs are usually pretty big.. not sure you'd ever shear that off? But Ti can be crack prone if the manufacturing process is not controlled well. so these are probably 6AL4V ti I guess? What do those cost now days?

The mast tang bolt is 1/2 inch diameter. I had it made from bar stock and made sure there were no threads in the bolt shear plane. Thanks for information.

[Stumble]

F10,

With few exceptions I am convinced that Ti should replace stainless everywhere on boats. It's stronger, lighter, more corrosion resistant, lasts for ever, etc...

The one major problem I am aware of is with ti threads. Not for something like chainplate bolts that are tightened down once then ignored for decades but in applications like turnbuckles on race boats that are adjusted daily. For deck fittings and the like ti is my preference by a long shot.

For a mast tang so long as you isolate the aluminium and Ti from each other you are fine. You need to do this with stainless (there is a real debate about which is worse ti-aluminium or stainless-aluminium btw). In this application the shear strength of ti should be more than sufficient but tangs are generally in compression, not shear anyway.

As always note that I am an attorney NOT an engineer and if you need specific advice I would suggest speaking with one, or calling Brion Toss for his input. He has a lot of experience installing ti mast fittings and rigging hardware, and I would consider his opinion close to definitive.

[sailon46]

Originally Posted by Stumble

F10,

With few exceptions I am convinced that Ti should replace stainless everywhere on boats. It's stronger, lighter, more corrosion resistant, lasts for ever, etc...

The one major problem I am aware of is with ti threads. Not for something like chainplate bolts that are tightened down once then ignored for decades but in applications like turnbuckles on race boats that are adjusted daily. For deck fittings and the like ti is my preference by a long shot.

For a mast tang so long as you isolate the aluminium and Ti from each other you are fine. You need to do this with stainless (there is a real debate about which is worse ti-aluminium or stainless-aluminium btw). In this application the shear strength of ti should be more than sufficient but tangs are generally in compression, not shear anyway.

As always note that I am an attorney NOT an engineer and if you need specific advice I would suggest speaking with one, or calling Brion Toss for his input. He has a lot of experience installing ti mast fittings and rigging hardware, and I would consider his opinion close to definitive.

Hey stumble, I share your excitement about titanium vs, ss but as far as weight check the chemistry periodic table and titanium is as heavy as lead ss is 4 times lighter almost. So where is the weight gain you are talking about.
Its good for stink boaters they got the engines to carry the load.
For what is worth
Ernie on the Mary Jane

[reed1v]

Originally Posted by F10

I am in the process of replacing all my chain plates (and bolts) and my mast hardware with Grade 5 Titanium. Have all the parts in hand and will be installing during next few weeks. Boat is located in harsh tropical environment thus the choice for the Ti Gr5.

Does anyone have any real life experience with Ti that they can share any things to look out for or avoid? I am replacing the mast tang bolts with Gr 5 Ti and have heard shear strength for Ti is less than 316 ss however that is not what I find on publish literature.

The best fittings are bronze or monel. Strong, non corrosive, and will normally not react with other metals to any appreciable degree. Way way better than stainless and less brittle than titanium. Who sold you on titanium?

[bsurvey]

I might suggest a thing sheet of G 10 for isolation material between the tangs and the mast

[Dockhead]

Originally Posted by sailon46

Hey stumble, I share your excitement about titanium vs, ss but as far as weight check the chemistry periodic table and titanium is as heavy as lead ss is 4 times lighter almost. So where is the weight gain you are talking about.
Its good for stink boaters they got the engines to carry the load.
For what is worth
Ernie on the Mary Jane

Ti weighs 4.43g/cc
and 316 stainless is 8g/cc -- almost double.
Lead is 11.3 -- nearly triple.

Since the ultimate tensile strength of Ti is nearly double that of 316, the specific strength -- strength per unit of weight -- is nearly quadruple. And that's just plain old titanium -- aerospace alloys are far stronger still.

For the record. I think you're reading your tables backwards.

Titanium is light and strong, but that's not the main attraction for us -- it's impervious to sea water corrosion and does not suffer from crevice corrosion. I agree with Stumble -- it's a killer app for sailing despite a few challenges. I hope its use becomes more widespread.

[Stumble]

Originally Posted by reed1v

The best fittings are bronze or monel. Strong, non corrosive, and will normally not react with other metals to any appreciable degree. Way way better than stainless and less brittle than titanium. Who sold you on titanium?

Lord not his again... Titanium is not brittle in the sense than most people use the term. In engineering brittle refers to a material with a small difference between its UYS and UTS expressed as a percentage the total UTS.

So for G5 titanium it comes out to be about 7% which from an engineering standpoint is a relatively brittle materials....

When you look at the actual numbers however....

Alloy....................UYS........UTS .....delta.......brittleness
G5 Ti..................128ksi....138ksi.....10ksi.... ...7%
6061 aluminium...8ksi........18ksi....10ksi.......55%

Keep in mind that ti deforms under load relatively easily, without crossing its UYS so it returns to its original shape. This is why titanium framed glasses can be tied into knots without being permanently distorted.

As for who sold me on titanium... First it was the maxi sled program I was part of, then the titanium fab company I worked for, then my own personal use of it on multiple boats, then the engineers I worked with and spoke too.

Once you get past its there are few places on a boat where titanium wouldn't be the prefered metal over stainless from an engineering standpoint.

[estarzinger]

I had quite a bit of experience with Ti, when I did 6 sigma at ge aircraft engines.

I agree it has nice properties.

But it creates engineering challenges . . . . And high level yachting has struggles with those challenges. Just for example . . . . There were a whole bunch of tI ram failures in both Volvo and imoca, and a snapped off tI keel after only 10 days use (Marc Guillemot's ) keel that simply broke off. Most "forming" processes are difficult - welds are not good under load.

Frankly in aerospace, composites have replaced quite a bit of the Ti

[Cheechako]

Originally Posted by sailon46

Hey stumble, I share your excitement about titanium vs, ss but as far as weight check the chemistry periodic table and titanium is as heavy as lead ss is 4 times lighter almost. So where is the weight gain you are talking about.
Its good for stink boaters they got the engines to carry the load.
For what is worth
Ernie on the Mary Jane

You got your numbers wrong somehow. Ti is heavier than Aluminum but much lighter than steel or SS.
Other:
Ti is very resistant to corrosion, but it can be very crack prone also.... especially if anything in the manufacturing process is not done properly. I worked with it for many years stamping, welding, superplastic forming, cold forming , machining etc.
Ti can ignite and burn from machining too aggressively. Normal fire extinguishers will not put the fire out.
I replaced the bilge tank in the boat in my avatar with 6AL4V tank. That was a great place to use it! The SS corroded thru in 7 years from new in that damp wet environment.

[Wind River]

Does anyone know a good source for titanium fasteners?

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