Broken mast - Splicing

[the dude abides]

Hi All,

I suffered a fractured chain plate while 30NM off shore. My yacht is a Slocum 43, very similar to a 42 Tayana. Broke my mast. It fractured by the first spreader and has peeled down about 200mm. It is an aluminum Isamat mast. Anybody out there spliced a similar mast or have a firm opinion on this. I would like to get an expert opinion from somebody that may carry weight with the insurance company in case we have a disagreement as well, if possible. I am in Thailand Phuket by the way. Thanks in advance. Cheers

[GordMay]

You might contact Sparcraft, or one of their distributors:
SPARCRAFT - USA [ex CHARLESTON SPAR, INC.]
3901 Pine Grove Circle
CHARLOTTE NC 28206 USA
Phone: 704 597 1502
Fax: 704 597 0961
Email: sales-us@sparcraft.com

➥ Charleston-Spar - Mast - Boom - Riggings - Fitting - Vangs

Local Distributors ➥ Distributor localization -Charleston-Spar

[the dude abides]

Thank you. Much appreciated.

[skipmac]

Due mainly to shipping restrictions many sailboat masts (including mine) are two pieces joined with a sleeve. Done properly you need a bit that is an exact fit for your mast that inserts into both ends and is then drilled, tapped and machince screwed together.

As I recall the insert in my mast is about 4' long so 2' on each side of the joint. In your case you might need a longer insert to extend beyond the damaged and bent sections.

If an exact fit sleeve isn't available from commercial sources perhaps a good local machine shop could build one.

[tkeithlu]

You could make up for an imperfect fit of the splint by packing it with epoxy as well. The goal is even distribution of the stress.

You brought back a memory for 1962 of my skipper shipping a new 56' mast from California to Florida by air. It disappeared at the Chicago airport. Never found it.

[Manateeman]

I think you ought to look at your chain plate situation first. There is a lot on the web about this.
Prior advice is correct. If you cannot find a section of the original extrusion, a good fabrication shop can bend and weld up a splice section and then you can fill up the difference. Lots of info on the web as how to splice masts.
This is not a huge spar so consider finding an entire replacement even if you have to motor somewhere to get it. Please post photos of your existing chainplates.
Happy trails to you.
Mark and sleeping manatee crew.

[skipmac]

Originally Posted by tkeithlu

You could make up for an imperfect fit of the splint by packing it with epoxy as well. The goal is even distribution of the stress.

Exactly.

Originally Posted by tkeithlu

You brought back a memory for 1962 of my skipper shipping a new 56' mast from California to Florida by air. It disappeared at the Chicago airport. Never found it.

An entire 56' mast? How could you not notice a 56' mast laying around somewhere? And what would some random crook want with such a thing if it had been stolen?

I am astonished. I have had shipments misdirected and even lost before. The railroad once misplaced a car loaded with several thousand gallons of extremely toxic chemicals my company was shipping from Houston to OK.
Finally showed up in Utah 2 1/2 weeks later but losing a 56' mast? That almost defies belief.

[Scorpius]

Scorpius's mast was salvaged from one that broke in a previous boat and it has lasted well for just about 40 years. However it is larger in cross-section than would be necessary for Scorpius and was shortened considerably in the repair process (the previous boat was quite a bit bigger - with a much bigger mast). It also helped that the repair was carried out by an absolutely fabulous metal worker and welder (who also built Scorpius). Done well you should have no problem with the repair.

However the earlier comment about the chainplates should also be carefully considered. You don't want to spend a lot of money fixing the mast when another chainplate could let go and bring the mast down again. Imbedded stainless chainplates are disasters waiting to happen.

[Jack C]

I have spliced a mast on a smaller boat and the local boatyard recently spliced a large catamaran mast that broke a few feet off the deck. From your pictures the break appears to be at the spreader, same as with my mast crack. The bolt going through the mast attaching the spreaders was loose resulting in an oval hole and stress cracks. Luckily we found the problem before the mast broke.

If you have a fractional rig then a splice at the spreader is not good. A bend in the mast of a fractional rig at the spreader does not go well with a splice.

If you have a full rig then splicing may work. You will need to unstep the mast. Then trim the broken ends so that they are 90 degrees to the mast section. Measure how much length you have lost. Then you will have to make an insert or have one made. Pieces of broken mast can sometimes be adapted to make an insert. If its the same profile as your mast, take a 4' piece, remove or slit inner sections and replace the track section with a slot. Then squeeze the piece using serious clamps so that you can insert it in one side of the mast. You will have to remove any inner sections in the mast for 2' in either direction. Then add thin epoxy to the outside of one half of the insert. Insert in a mast section and rivet in place using monel or stainless rivets (not aluminium rivets). Add an isolator such as tefgel and find a heavy duty pop riveter. Add tefgel to the end of the rivet as a glue to prevent the rivet rod from sliding around. Also preferably rivet from under rather than over the mast. Gravity helps the rod to drop down between riveter squeezes.
Once one side of the mast is done, push the insert into the other side of the mast. Make sure that the slot is aligned. Again use epoxy as glue and then rivet.

Make sure that the spreader attachment is sound and that it will not cause another break. If the attachment uses a through bolt create a sleeve with length being the mast diameter at the hole, for the bolt, so that tightening the bolt does not distort the mast.

The lost mast length due to trimming needs to be made up. This can be done by not fully inserting the sleeve and adding a band to strengthen the insert. This may already be needed to create a new spreader attachment.

Alternatively if the lost length is small, the stay turnbuckles may be able to take up the space as long as there is enough space between the sail head plate and shive when the sail is hoisted. You may have to move the gooseneck down.

Adding a spacer under the mast could help if there is not enough stay turnbuckle adjustment but this will not solve the problem of the sail being too long.

So think of the ramifications of mast shortening due to trimming the ends. Find the cause of the mast break and inspect the mast carefully before starting. If there was one weakness, there maybe others.

I am not a professional rigger and this advice should be carefully considered. The decision and responsibility is yours.

[CF32907]

CaptVR here,
I'll make this short and not so sweet. It may be able to be repair with a small section and internal sleeve. Well and good if a rigging shop does the repair. They have the expertise and a healthy insurance policy if something fails.
You try to do it yourself and it fails, your insurance will not cover the future damage. Not to say if someone is injured or killed by a failure in the future, you will be responsible. Possibly criminally if it's found you used improper epoxy, nuts, bolts, etc. Not to say how crappy you would feel if that were to happen. I have done spar failure on wood spars for 55 years, I have repaired a couple aluminum spars with factory sleeves, with directions from the manufacturer, I had a licensed shop and surveying credentials, and still was hinky about the liability end.
All these fellow sailors telling you to make sleeves, epoxy fill, you really don't want to do that. There is engineering of flexture in aluminum masts, repairs can't be to rigid nor to flexible, can't have hard spots nor pressure points in the spar.
Like I said, it can no doubt be fixed, but in the case of a mast, bite the bullet and have a pro shop due it. You will be surprised how much better youl sleep......
Happy sailing all... Capt. Vince Rakstis, Ret. MS St.Petersburg, Fl.

[Boatguy30]

Let us know how it works out. Chainplates on those boats are notoriously bad and I’m unsure why you’d be able to get insurance without prior chainplate replacement. Perhaps should be in the “marine insurance cartel thread”

[CF32907]

CaptVR here again;
You did not mention why the chain plate failure. Are these internal chain plates. If so are the encased if frp and sealed. Are the enter and exit points through the deck sealed on both sides. If so, you probably have some oxygenation to the SS, totally destroys the integrity of the chain plates. REGARDLESS, PULL AND INSPECT ALL DECK PASSAGE AREAS OF ALL THE CHAIN PLATES. Never seal the bottom sides of any deck passage hardware, just the tops at top deck level. You want to insure air (oxygen) is getting to that hardware and is not in a damp oxygen starved crevice. Often called crevice corrosion.
Hope this gives all some insight on stainless steel not being so impervious to elements.
Happy sailing all... Capt. Vince Rakstis, Ret. MS St.Petersburg, Fl.

[Boatguy30]

Those boats chainplates are glasses in behind the then teak lined hull. Come thru the deck inboard of the cap rail. Close to impossible to replace, but relatively easy to ad external teardrop shaped to bolt outside original.

Are insurers ignorant of these issues?

[iann]

Splicing is easy as explained above often the problem is that sections will be slightly bowed near break and impossible to get straight to tune out .

[floydmiami1]

Not too difficult,I spliced mine on a 44 csy that had toppled over during Irma and unfortunately the mast broke.Used a 4 1/2 foot sleeve,cut a slot up the sleeve compressed it with ratchet belts ,banged in one side with a block of wood and sledge hammer and used a come along to pull the other side in as I released the ratchets.Drilled and tapped 1/4 20 screws on both sides would have preferred to use rivets but had to use what’s available Just because a welder was right there where I was working on the mast I ground out a vee where it mated and welded a nice bead around it. Hope that helps