Ways to Add 6ft to the BOTTOM of a mast?

[bsurvey]

the problem is finding an extrusion like the one you have along with an inner sleeve if you install an inner sleeve between the two sections it will make it super strong and can be held together with pop rivets of tapped and bolted

[Searles]

If adding 6ft to the lower section of the existing spar the geometry of the spreaders and the D2and D3 will change how the spar will react under sail,add to the spar is the least of the problem,especially in a performance yacht . Just the way it is .⚓️👎🏼⛲️

[Dsanduril]

I apologize for the quality of the photo, have never taken one for this specific purpose. Our mast was delivered from the factory 20 years ago with ~5' splice at the bottom. Same for every one of our sisterships I've been aboard. There's an internal sleeve. You can see the join where the extrusion changes color and the fasteners running up and down the face of the mast into the sleeve. Only real difference, in our case the gooseneck is attached to the sleeved section of the mast - don't know how much difference that makes.

I suspect the difficulty for you, with a used mast, would be finding the section of extrusion and sleeve to match the existing mast.

[Chotu]

Here’s a picture of the exact same type of rig.

See how it’s on a catamaran with a really low deckhouse?

My deckhouse is really high. So I want to bring up the boom to the deckhouse height it needs to be and in the price lengthen there mast by 10%.

What’s the best way to accomplish this, throwing my original parameters out the window?

[Chotu]

Originally Posted by Dsanduril

I apologize for the quality of the photo, have never taken one for this specific purpose. Our mast was delivered from the factory 20 years ago with ~5' splice at the bottom. Same for every one of our sisterships I've been aboard. There's an internal sleeve. You can see the join where the extrusion changes color and the fasteners running up and down the face of the mast into the sleeve. Only real difference, in our case the gooseneck is attached to the sleeved section of the mast - don't know how much difference that makes.

I suspect the difficulty for you, with a used mast, would be finding the section of extrusion and sleeve to match the existing mast.


Attachment 231568

Wow! Thanks for this picture.

Yes, finding the piece to add would be the most difficult part, I think based on all the input so far.

[billgewater]

Check out the second hand masts on the web. The range is unbelievable and the prices seem (to me) to be bargains. OK there may be transport issues but the cost of many of these masts seems to be very low compared to the fabrication costs of a base column or platform.
If you did build a base remember that the shrouds, fore-stays, internal wiring etc. and also the position and angles of the spreaders may need to be changed to provide the strength features the original rigger/designer stipulated. If the mast goes up by 6 ft then you may have to reposition the chain plates for the lowers as the angles involved would change.
A broken or collapsed mast is not a happy event, particularly if the surveyor would not pass the rigging for your insurance policy.

Mast sections are measured in lateral and for and aft inertial factors and the rigging is designed to match these factors and the loadings expected for the particular boat. In other words, its a fairly complex matter. I would try contacting the boat designer/company and getting their input.

Also, ask yourself what a base would look like. Agricultural? It may look completely out of place on an otherwise elegant boat.

[Chotu]

Originally Posted by billgewater

Check out the second hand masts on the web. The range is unbelievable and the prices seem (to me) to be bargains. OK there may be transport issues but the cost of many of these masts seems to be very low compared to the fabrication costs of a base column or platform.
If you did build a base remember that the shrouds, fore-stays, internal wiring etc. and also the position and angles of the spreaders may need to be changed to provide the strength features the original rigger/designer stipulated. If the mast goes up by 6 ft then you may have to reposition the chain plates for the lowers as the angles involved would change.
A broken or collapsed mast is not a happy event, particularly if the surveyor would not pass the rigging for your insurance policy.

Mast sections are measured in lateral and for and aft inertial factors and the rigging is designed to match these factors and the loadings expected for the particular boat. In other words, its a fairly complex matter. I would try contacting the boat designer/company and getting their input.

Also, ask yourself what a base would look like. Agricultural? It may look completely out of place on an otherwise elegant boat.

This IS the second hand mast I bought.

I AM the original rigger.

There is NO NEED for me to contact the designer as I have the rig plans right here in front of me. I bought this mast SPECIFICALLY due to the fact that it’s the right one for this boat.

I paid $1000 to a naval architect too to make sure it’ll work.

I’m just trying to put 10% more length and get the boom in the right spot.

I don’t have chain plates.

I already have to buy the new standing rigging. Why not? I can do that before the mast goes on and have a ready to go boat.

I agree about it looking agricultural though. Looks like the internal splice is the best bet to avoid any comparison to farming equipment. It’s a really simple oval section so I’m hoping I can find a piece somewhere.

Not to you, bilgewater, but..

Why do I get so annoyed at these threads sometimes? You have to repeat your story over and over and over and over.

For those who haven’t seen all the other threads:

1) this IS the used mast I bought

2) I DID move it myself 100 miles with a pickup truck

3) it WAS all calculated by a naval architect I paid $1000 to to do the inspection and ixx, iyy, mass, etc

4) I don’t want any more naysayers. I didn’t ask if I can do this. I asked what’s the best way to do it. If I listened to all the naysayers in boating my whole life I’d be sitting in the old armchair typing away on my computer doing nothing and going nowhere.


Thank you very much for all the good posts here, and there are quite a few, but correcting all the naysayers or people who think I’m keel stepping a monohull mast, doubling its length with 500lbs of steel is exhausting.

[thunderhoof]

Originally Posted by Lake-Effect

If you don't mind my asking, roughly how much did the repair cost?

Repair was over 20 years ago so I doubt any number I remember would be valid. I remember it being 20% of replacing the mast with new and re-rigging. Check with the best riggers in your area.

[Chotu]

Originally Posted by thunderhoof

Repair was over 20 years ago so I doubt any number I remember would be valid. I remember it being 20% of replacing the mast with new and re-rigging. Check with the best riggers in your area.

And you paid to have that done, right?

Didn’t drill and screw your own like in the YouTube Os2Dude posted?

[Montanan]

Construct an internal or external sleeve. See if you can purchase a bottom length section of a similar mast and then combine your long mast to the stub end.

References:

https://www.youtube.com/watch?v=ogZm_ghmkY0

https://www.youtube.com/watch?v=8dhp-7g2j68

If you do any welding of attachments one likely should reheat treat the mast to strength around the weld which is a major task finding an oven long enough or at least around the welded section.

[thunderhoof]

Just wanted to add one thing-
There is a good set of dimensioned spar cross sections at:
https://www.rigrite.com/A-Main/spar_M.php
Once you identify the section you can more easily locate a matching piece.

[Lionshooter]

I've done it.
In 1980, a Catalina 27 got hit by another boat and the mast broke a foot above the spreaders. I had a rigging business so it fell on me. I had never done this before, but hey, show me the $$. There was no Google or Cruisers Forum back then. I had to get creative and invent something. So...
1. Went to Alvin's boatyard, which is a 5-acre retirement community for abandoned boats, and found an identical mast extrusion.
2. Removed the spreaders and brackets
3. Cut 3' out of the original mast to get past any deformities from the collision.
3. Cut a 3' splice to replace what I had removed.
4. Cut a 6' piece to slide inside, but had to remove the sail track in order to compress it enough to fit.
5. Replaced the spreaders.
6. A boatload of rivets later, the boat was sailing again.
It wasn't real pretty but if you were sailing past at 5 knots, you wouldn't have noticed.
It wasn't difficult, just time-consuming. Took up the whole day.

[AKA-None]

You don’t need an oven to stress relieve a section of mast you need heat blankets. Used them often in ship building for large parts

[Uncle G]

Chotu said:


"There is NO NEED for me to contact the designer as I have the rig plans right here in front of me. I bought this mast SPECIFICALLY due to the fact that it’s the right one for this boat.

I paid $1000 to a naval architect too to make sure it’ll work.

I’m just trying to put 10% more length and get the boom in the right spot. "



So you bought the right mast, checked it with a naval architect - and now it's far too short?

[Chotu]

Originally Posted by Uncle G

Chotu said:


"There is NO NEED for me to contact the designer as I have the rig plans right here in front of me. I bought this mast SPECIFICALLY due to the fact that it’s the right one for this boat.

I paid $1000 to a naval architect too to make sure it’ll work.

I’m just trying to put 10% more length and get the boom in the right spot. "





So you bought the right mast, checked it with a naval architect - and now it's far too short?

Uncle DipS: It needed a 10% lengthening. Any mast can be lengthened. What is wrong with you?