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

[SeaSloth]

I had to get my mast repaired with an internal sleeve. It was specifically made for the model of mast. As others have noted it was put together with precision riveting. If you could get a section of the same mast model and a sleeve it you could extend it. I can send you some pictures of my repair.

The sleeve was $1K. My mast is out of production so I had to go to the used market. No idea what yours would be. The labor was about $10K. The rigger had never done one before and really took his time not to ruin my mast and cost the yard to replace the whole thing. Their rough estimate for a new mast was about 20K not counting rigging, sails, etc, which I guess would have run to another 20 to 30K all said and done.

It isn't just the length of the mast you need to be concerned with. When the original mast length was specified by the designer they likely also specified the mast must have a minimum I^4 rating to handle all of the bending forces applied to it. If your lengthened mast doesn't meet that minimum you could suffer a mast failure.

[JBsurfin]

Originally Posted by Chotu

Pretty sure that’s because, like many people here on this forum and in life in general, you’re living in constant fear and self doubt.

Guess what? The people putting in a sleeve are doing the same thing as show on the YouTube videos above. And you know what else? They’re only people like you or I as well. Hell, if you order a new mast these days it comes in sections you put together yourself just like in the videos.

Anyone can do anything at all, if they’re willing to learn.

I can assure you with a A personality that I have, I live my life well on a edge. far further than you will ever do. MOST people are not fabricators.. I come from a boat building family.. And I would still refer to an expert. That's why they have experts to refer to. I didn't say I would have them do the work.. Everyone has choices in life, I've learned very early on in some of the many crazy hazardous adventures I've been on.. know your limitations and you will come back alive. Now crawl back into your cubby cabin. Your safe

[Chotu]

Originally Posted by SeaSloth

It isn't just the length of the mast you need to be concerned with. When the original mast length was specified by the designer they likely also specified the mast must have a minimum I^4 rating to handle all of the bending forces applied to it. If your lengthened mast doesn't meet that minimum you could suffer a mast failure.

Ixx and Iyy already calculated

[SeaSloth]

Originally Posted by Chotu

Ixx and Iyy already calculated

Sounds like a fun project. I can send you the pictures of mine mid-process if you think it would be helpful for you.

Good luck.

[Aethelwulffe]

No mention of it, but I assume this is a deck-stepped mast? Is there some reason why you would not just move the boom position and re-cut the sail as a loose-foot, or move to a wishbone for this kind of application? Is this some sort of in-mast furling?



-Adding 6 fee to the stick where you say the gooseneck needs to be six feet higher than it already is...assuming that it is at least a few feet off the deck or coachroof currently, a gooseneck and boom (assuming not a wishbone) completely out of reach by hand seems...uh...


Considering that will need to change absolutely everything about the boat's rig, and that you will be increasing the moment of mass of the mast greatly (think of the force created by adding 20 pounds of pressure on a 50'+ lever, oscillating moment, then the much higher center of effort of the sails), this is not trivial. The available spreader angle and rig rigidity will be significantly reduced as well. Of course if there was a standard rig option for this boat that was 6' taller, this might be within design parameters, but most of those really tall rig versions tend to get chopped down quick when they head somewhere like the South Texas Coast where they actually have wind.
-In light of the whole project, the cost of a new a new spar section spliced in isn't that big of a deal. You pull off the mast-step, add the section, totally re-calculate all the standing rigging, and add a third or fourth set of lower stays along with stay diamonds and a new set of spreaders...all to get the boom high up out of reach.


The "put it on a box" idea, if they are not talking about building up the keelson and mast-step with some kind of compression member to raise a keel-stepped mast, is nuts. The box on deck would spread the compression onto the deck. The force of the mast step needs to be transmitted directly to the compression post, which is transmitted directly to the keel, and transverse loads from the chainplates need to offset each other with a good deck beam structure. It is easy to find many examples of even very small trailer boats where attempting a "compression arch" or the like resulted in a failed deck, a loose rig, and a junk boat. Your mast does not just sit against the compression post with a fairly constant force that may increase or decrease. It gets *pumped*, shook, and all of that invisible hammering that is going on depends on very direct transmission of the load, and no sort of arch support will have that level of rigidity. It will flex, it will move, it will deform.


Mast tabernacles are awesome. They are also pretty much the domain of keel-stepped masts, at least any that are not hinkey. In no case do you use a tabernacle to INCREASE rig height. Usually you wind up doing the opposite. A simple extension extrusion is much more cost-effective and safer.


-Assuming you can get the rig balanced and rigid, and you can still sail the boat with a boom some 9' + off the deck and some 15+' higher than the waterline, and you have avoided whatever it is you want to avoid (dunno, you want it over a radar arch?) then the use of a typical spliced mast will not in the least be a worry. Long ago, when I was laying out a tapered birds-mouth joint hollow mast some 60' in length, I asked Grandpa about how I should stagger the scarph joints in the ~18' pieces of spruce we had. He replied "If you make the joints right, you don't need to worry about where they are. If you don't make the joints right, it won't matter where they are."

[Chotu]

Originally Posted by SeaSloth

Sounds like a fun project. I can send you the pictures of mine mid-process if you think it would be helpful for you.

Good luck.

Yes, that would be extremely helpful. Thank you!

[Martkimwat]

The mast on my Tradewind 33 which is original as far as I can tell, is built in two halves with a sleeved join about 6 or 7 feet from the base. it is connected with multiple flush rivets over what I guess is a sleeve about 6 feet long. It looks like a professional job and I'm pretty sure would not have been done if there was any doubt about structural integrity. I cannot show pictures because I spray painted it about 8 years back and the rivets, being flush, are not now visible, neither is the join.( I did a very thorough job of the paint spraying)

[robertmfranklin]

Rather simple. Many people have done something similar when the bottom of an aluminum mast sitting on a steel step (crazy) has had substantial corrosion.

You find out who manufactured the mast. You order a 6 foot piece of extrusion. You get a 2 foot peice of extrusion. You take the two foot piece and cut out the sail track. Then take a couple clamps and squeeze the top of the two foot extrusion until it slides one foot into the existing mast. Take the 6 foot extrusion and slide it onto the remaining one foot of the squeezed piece.

Done. You don't need to do anything else except a few neatly installed flat machine screws drilled and tapped into the extrusions to keep them in place. Aluminum screws would be best, but everything else on the mast is probably stainless, so why fuss.

All the pressure is downward the 1 foot intrusion both up and down is probably plenty. The chance of failure at that joint is probably zero. If a shroud breaks, the mast will fracture somewhere else, not there.

This is actually an easy job compared to some of the other solutions that have been proposed.

The hard part is finding who made the mast (maybe not so hard).

You can do everything with hand tools, a circular saw and a small sledge hamnmer to couple the extrusions together.

[Chotu]

Originally Posted by Aethelwulffe

No mention of it, but I assume this is a deck-stepped mast? Is there some reason why you would not just move the boom position and re-cut the sail as a loose-foot, or move to a wishbone for this kind of application? Is this some sort of in-mast furling?



-Adding 6 fee to the stick where you say the gooseneck needs to be six feet higher than it already is...assuming that it is at least a few feet off the deck or coachroof currently, a gooseneck and boom (assuming not a wishbone) completely out of reach by hand seems...uh...


Considering that will need to change absolutely everything about the boat's rig, and that you will be increasing the moment of mass of the mast greatly (think of the force created by adding 20 pounds of pressure on a 50'+ lever, oscillating moment, then the much higher center of effort of the sails), this is not trivial. The available spreader angle and rig rigidity will be significantly reduced as well. Of course if there was a standard rig option for this boat that was 6' taller, this might be within design parameters, but most of those really tall rig versions tend to get chopped down quick when they head somewhere like the South Texas Coast where they actually have wind.
-In light of the whole project, the cost of a new a new spar section spliced in isn't that big of a deal. You pull off the mast-step, add the section, totally re-calculate all the standing rigging, and add a third or fourth set of lower stays along with stay diamonds and a new set of spreaders...all to get the boom high up out of reach.


The "put it on a box" idea, if they are not talking about building up the keelson and mast-step with some kind of compression member to raise a keel-stepped mast, is nuts. The box on deck would spread the compression onto the deck. The force of the mast step needs to be transmitted directly to the compression post, which is transmitted directly to the keel, and transverse loads from the chainplates need to offset each other with a good deck beam structure. It is easy to find many examples of even very small trailer boats where attempting a "compression arch" or the like resulted in a failed deck, a loose rig, and a junk boat. Your mast does not just sit against the compression post with a fairly constant force that may increase or decrease. It gets *pumped*, shook, and all of that invisible hammering that is going on depends on very direct transmission of the load, and no sort of arch support will have that level of rigidity. It will flex, it will move, it will deform.


Mast tabernacles are awesome. They are also pretty much the domain of keel-stepped masts, at least any that are not hinkey. In no case do you use a tabernacle to INCREASE rig height. Usually you wind up doing the opposite. A simple extension extrusion is much more cost-effective and safer.


-Assuming you can get the rig balanced and rigid, and you can still sail the boat with a boom some 9' + off the deck and some 15+' higher than the waterline, and you have avoided whatever it is you want to avoid (dunno, you want it over a radar arch?) then the use of a typical spliced mast will not in the least be a worry. Long ago, when I was laying out a tapered birds-mouth joint hollow mast some 60' in length, I asked Grandpa about how I should stagger the scarph joints in the ~18' pieces of spruce we had. He replied "If you make the joints right, you don't need to worry about where they are. If you don't make the joints right, it won't matter where they are."

Grandpa was a smart man. I agree with him.

Everything else? You need to do a little reading!

You didn’t even read the thread before posting this manifesto of assumptions

[Chotu]

Exactly!

The fear in some of these nervous nellies is just crazy. LOL

It’s a hollow post in column. People are treating this like I’m building Elon Musk’s next rocket, which I could also do with a team and a bunch of ordinary humans did.

It just amazes me how frightened people are of learning how to do something then doing it.

I guess that’s what makes me not like those of you living in fear.

In the end, I’ll probably try to sub it out anyway because I’m trying to get sailing, not building. However, if the quote is outrageous, it’s an easy task now that I found out how to do it properly.

That was the point of the thread.

Not if, but how to do it.

Originally Posted by robertmfranklin

Rather simple. Many people have done something similar when the bottom of an aluminum mast sitting on a steel step (crazy) has had substantial corrosion.

You find out who manufactured the mast. You order a 6 foot piece of extrusion. You get a 2 foot peice of extrusion. You take the two foot piece and cut out the sail track. Then take a couple clamps and squeeze the top of the two foot extrusion until it slides one foot into the existing mast. Take the 6 foot extrusion and slide it onto the remaining one foot of the squeezed piece.

Done. You don't need to do anything else except a few neatly installed flat machine screws drilled and tapped into the extrusions to keep them in place. Aluminum screws would be best, but everything else on the mast is probably stainless, so why fuss.

All the pressure is downward the 1 foot intrusion both up and down is probably plenty. The chance of failure at that joint is probably zero. If a shroud breaks, the mast will fracture somewhere else, not there.

This is actually an easy job compared to some of the other solutions that have been proposed.

The hard part is finding who made the mast (maybe not so hard).

You can do everything with hand tools, a circular saw and a small sledge hamnmer to couple the extrusions together.

[Aethelwulffe]

No assumptions, and I did some significant comprehensive reading. Many of the elements I referred to were separate replies to included assumptions. Perhaps not all of each of the six pages, but certainly the first page and some basic elements elsewhere. Sorry to offend with a "Manifesto". Note that I never post "you should" or "you must". These were my observations, not really advice. Forum of ideas, because we really don't only post here for problem->solution reasons, do we?
-Cheers.

[robertmfranklin]

Only thing I can add is, I too did an extensive grid of machine scres to keep the extrusion and in inned sleeve together. Too late I realized that was ridiculous. All you need is one screw on each side of the mast above and below the connection.

Tell me how that sleeve is ever going to move?

[sailorladd]

You don't say whether it is made of wood or aluminum... I'm assuming it's the latter and I'm wondering if you can obtain some of the original profile aluminum to use as an inner sleeve... you can slice one side and cut out enough to be able to slide it inside the bottom, forming the inner sleeve allowing about twelve inches to stick out and twelve inches to attach (rivets) inside... welding would be logistically challenging... If it's a wooden mast it can be made by scarfing a compound angled scarf with epoxy glue (the dreaded epoxy It's a compression strut remember...

[Chotu]

Originally Posted by Aethelwulffe

No assumptions, and I did some significant comprehensive reading. Many of the elements I referred to were separate replies to included assumptions. Perhaps not all of each of the six pages, but certainly the first page and some basic elements elsewhere. Sorry to offend with a "Manifesto". Note that I never post "you should" or "you must". These were my observations, not really advice. Forum of ideas, because we really don't only post here for problem->solution reasons, do we?
-Cheers.

Cheers.

What gets frustrating is you posting about 9foot boom height, “changing everything on the rigging “, etc etc making wild assumptions when it was already all discussed up thread.

In fact, this thread is closed. Done. Solved. It’s already been figured out.

Why would anyone just come in here, not read the thread and then make wild assumptions about the setup when everything is already in the thread and detail all these imaginary problems that don’t exist?

I’m sorry. I’m not upset with you I’m particular. I start a lot of threads on details to fill in any areas I’m deficient on. To learn.

It’s maddening to see a post like yours not grounded in the reality of the discussion, the specifics of the question, or others simply saying it can’t be done.

ANYTHING can be done and it has thousands and thousands of times over. So all the nervous nellies really get irritating to be honest.

I’ve done a lot I’m my lifetime. Created a lot of things. Some decades ago that are still in space and make the news once in a while.

Did you even gather this is new construction? That I’m not “changing “ anything? Did you notice that in the thread?

Did you see ixx abd iyy are already calculated and I of course have the rig plan for the boat I built?

Did you miss all that?

That’s what I get frustrated with too.

And I apologize. It’s not you I’m particular. It’s all the people who do the same thing. Dragging this thread out of the closed pile just to say it can’t be done.

See my how to move a mast thread for more information on things that “can’t possibly be done”. LOL

It’s stuff like that that’s just building up.

Yes, it’s the internet, I’m supposed to take it. Relax. Not worry about it.

But it polluted my threads which I am using to fill in gaps in my knowledge. And I have to read everything because there might be important information.

Again, not you. Just a general “I wish it wasn’t like this” post.

Maybe I need a break.

[OneBoatman]

Based on the date of your question you've probably already done what you thought is best. I wouldn't think just extending your mast 6ft from either end is such a good move because while you've considered the obvious things you have to change there is no doubt a couple you haven't considered. Since you you want to raise the gooseneck I wouldn't even consider extending from the top as this means you must relocate the gooseneck. Thus sleeving and extending from the bottom is the more logical choice. Don't overlook the extra cost to re-wire any lighting and instruments you have at the masthead, longer halyards and topping lift, clearances for a longer kicker, new stays all around and added sections of furler foil. Are you going to buy a larger jib or simply fly the one you have higher? Remember the raised location of your top swivel effects the lead angle to the turn at the crown and these must be such to prevent halyard wrap. If you go with at bigger jib in a desire to take advantage of the now bigger foretriangle this could result in reducing whatever pointing ability your cat already has and could give you unneeded trouble "getting the bow around" each time you tack. I would contact the builder/designer, if they are still available, and see what they have to say about the change before you play marine architect. Sail on sailor.