Getting a mast on a boat WITHOUT a real crane

[Chotu]

Originally Posted by Auspicious

Naval architect and marine engineer here. I agree with MicHughV. Just not a good idea. Hinging at the base of the mast (assuming deck stepped) is much more achievable. I know of a 60+' ketch that has hinged the main mast to fit under bridges on the ICW. It's a painful process that takes many hours but does not require any outside support.

It’s ok.

I don’t have the time for this extra work anyway. Maybe some year. A crane pull once in a great while isn’t very expensive anyway. $200?

Thanks for the import on that.

Now if I could only find an affordable spot to put the boat to work on it... my other thread is full of tumbleweeds on that. Lol

[wsmurdoch]

If you plan to lower or raise the mast yourself at some point, the clevis hole in at least one of the port and and one of the starboard chainplates should be on an extension line of the pin in the mast hinge so that that those shrouds do no go either tight or loose as the mast is raised or lowered, and they can thus supply stability to the mast. Otherwise, you will have to cob together some method of steadying the mast as it goes up or down.

[MicHughV]

We are on the edge of a lovefest here. *grin* Fully agree. So two professional opinions from people who don't know each other who are on the same page.


Dang...I thought we were onto something here, but Chotu doesn't want to play ball...

[Chotu]

Originally Posted by MicHughV

We are on the edge of a lovefest here. *grin* Fully agree. So two professional opinions from people who don't know each other who are on the same page.


Dang...I thought we were onto something here, but Chotu doesn't want to play ball...

Right?? When do we all agree about things on this forum? Ha ha. It has happened, finally.

But yeah. No extra tasks on the rig for now. I’ve been playing too many innings. I’m at like the 506th inning right now. I got called on account of rain, had to sit out the season on the injured list, you name it. So I gotta reduce the number of innings.

[MicHughV]

Bummer....but...if you could send pics or sketches of your situation, we could could better understand your situation...and modify our suggestions to suit...that way, we can likely draw up sketches or plans or something to aid you...you can send the beer later...

[Chotu]

Originally Posted by MicHughV

Bummer....but...if you could send pics or sketches of your situation, we could could better understand your situation...and modify our suggestions to suit...that way, we can likely draw up sketches or plans or something to aid you...you can send the beer later...

But I don’t want to do a tabernacle or other folding mast.

The thread is about lifting a mast off the ground and loading it on the deck of the boat without a crane.

I think the come alongs and rollers will do that just fine.

The thread has already been solved.

I’ll make a new thread about getting the rig on when the time comes.

[Sand crab]

I know the hinging part has been put to rest but I don't think it's as practical on a cat. It works better on a mono because many masts are keel stepped so you have something stout locking in the base. On a deck stepped mast the lower 6' part of the hinge would require additional mini stays which would be more clutter on the deck. I'd like to see a pic of this on a cat.


Brokers love to specify that the mast on a cat is deck stepped. Well, duh.
Rant over.

[Buzzman]

Nah, phooey. Much harder to self-raise a keel stepped mast. This is the one thing you DO need a crane of some kind for, as the mast needs to drop, slowly, but pretty well near vertically down through the deck.

Whereas a deck-stepped mast can have a simple hinge at the aft end of the base, and be hauled up by an extension to the forestay.

Again, those rollers you're contemplating to get the mast aboard? Keep in mind they might later be useful to roll the mast aft so the base can be then lowered onto the step and the hinge pin attached.

As someone else said up thread, you need one of the chainplate pins on each side to be in the same line and plane as the mastbase hinge pin, so those stays won't go loose or taut as you raise or lower the mast. A gin pole attached at 90 deg to the lower part of the mast, with a pully or roller at the end of it, provides the leverage necessary to lower or raise the mast to/from the deckhead. A big mast like yours a winch to control it would also make sense. Even the boat's own main winch will do.

Look on You Tube for methods used by trailer sailer boaters. There are several versions of this method. Some use the boats own stays to stabilise the mast side to side as it is raised, others used additional temporary fixed stays (how I raise mine) and the gin pole method is the simplest.

The advantage of using your own stays as stabilisers is this method then works equally well for lowering the mast part way so as to motor under low-ish bridges. If necessary you can even lower it completely to get under very low bridges.

Glad you like the 'simple' solution for getting the mast aboard. KISS principle is often the easiest as well.

[Sand crab]

Oops, sorry about that Buzz, I was thinking about hinging the mast from the 6' extension that the OP has to add. It would look sorta like this from a ComPac Suncat which is not a catamaran.

FWIW I have raised and lowered the deck hinged mast several times on a MacGregor 26

[Chotu]

Originally Posted by Sand crab

Oops, sorry about that Buzz, I was thinking about hinging the mast from the 6' extension that the OP has to add. It would look sorta like this from a ComPac Suncat which is not a catamaran.

FWIW I have raised and lowered the deck hinged mast several times on a MacGregor 26

Whoa!!!!!!!!

Now wait a second here.

This, if workable, could solve all my problems (and dreams) at once!!!

I have to add 6ft to the the bottom of the mast anyway. If the mast tipped backward at the 6ft mark, it would lay beautifully on the deckhouse. The forestay could control the whole thing, leaving the shrouds in place for the drop. The shrouds are swept back and would just loosen as you drop. Probably would need a forward facing gin pole to start that lift so the forestay could then crank it up the rest of the way. Couldn’t the forestay be put on a drum winch to just reel it in or out to raise and lower the mast with the use of a gin pole?

I probably wouldn’t even need the exact same mast section for the 6ft base piece since a plate could be installed there to make sure the contact between 2 similar (but possibly slightly different) mast sections would make perfect contact.

Sand crab: this is quite a solution. Kills every bird, plus a couple elephants with one stone.

I need to see where the problems will be with this.

I’m guessing the furler may make things a little tricky. Not clear on how the gin pole would work. You put it in place as you are lowering it, then move it out of the way once the mast is up? Thinking about it interfering with the foresail.
Lateral stability if conditions aren’t perfect when lowering the mast? Could a robust enough hinge be made to account for that? As in... the mast has a pretty good bury into the hinge and the hinge pin is very beefy to withstand side loading if the mast is trying to swing a bit laterally on moving it up or down?

This is really quite a solution.

And... this 6ft piece is very close to the deckhouse anyway, like you see on most cats, so the clutter factor for holding it in place isn’t so bad.

No mast splice needed either!!

I don’t think this idea would take any more time than splicing the mast and finding an exact copy spar section for the 6ft extension. This could possibly save time.

This idea has to be fully explored. It’s a great one.

[Sand crab]

I think that mast stub in the pic is keel stepped. That locks it in to facilitate the mast raising. If you could figure out how to do the same with your new stub then you are part way there. I'm not talking about keel stepping but the issue is the amount of bury. If you have a large space under your mast then you might be able to bury it enough to accomplish your goal. It's similar to the free standing mast also called an unstayed mast on some sailboats like the Freedoms. Eric Sponberg is a member here and he is the go to guy for that.

https://www.ericwsponberg.com/free-s...-mast-designs/

[Chotu]

Originally Posted by Sand crab

I think that mast stub in the pic is keel stepped. That locks it in to facilitate the mast raising. If you could figure out how to do the same with your new stub then you are part way there. I'm not talking about keel stepping but the issue is the amount of bury. If you have a large space under your mast then you might be able to bury it enough to accomplish your goal. It's similar to the free standing mast also called an unstayed mast on some sailboats like the Freedoms. Eric Sponberg is a member here and he is the go to guy for that.

https://www.ericwsponberg.com/free-s...-mast-designs/

I’m very familiar with the unstayed masts on freedoms, Eric Sponberg’s excellent work and have even met with Eric personally about this boat.

The laminations for taking the mast compression load are already baked into the main crossbeam it sits on at deck level. So doing a bury isn’t feasible for this boat. It would add a lot of weight and time, effort and expense.

I looked into this previously to do a rotating unstayed wingmast, but it was just too much of a modification and way too expensive and time consuming for this boat.

However, staying that little stub some other way with cables or boxes to secure it to the deckhouse and deck is totally doable and seems easier than my previous approach.

[Jammer]

Originally Posted by Chotu

The shrouds are swept back and would just loosen as you drop.
[...]
Lateral stability if conditions aren’t perfect when lowering the mast? Could a robust enough hinge be made to account for that? As in... the mast has a pretty good bury into the hinge and the hinge pin is very beefy to withstand side loading if the mast is trying to swing a bit laterally on moving it up or down?

The loads on the hinge pin would be huge as would be the torsional stress on the lower mast segment and the step. If the shrouds are swept back then you will would have to rig a lifting bridle to control lateral movement. The bridle segments would have to terminate at a location in line with the hinge pin but outboard of it as far as is feasible.

Probably would need a forward facing gin pole to start that lift so the forestay could then crank it up the rest of the way. Couldn’t the forestay be put on a drum winch to just reel it in or out to raise and lower the mast with the use of a gin pole?

[...]
I’m guessing the furler may make things a little tricky. Not clear on how the gin pole would work. You put it in place as you are lowering it, then move it out of the way once the mast is up? Thinking about it interfering with the foresail.

Generally the gin pole is placed between the base of the forestay and the mast. It need not be at a 90 degree angle and could slope forward (mast down) / downward (mast up) though this will increase some of the stress particularly the tendency for the gin pole to push upwards where it attaches to the mast. The furler should have no effect. Ordinarily the gin pole is removed and stowed at the conclusion of the mast work.

This is really quite a solution.
[...]
This idea has to be fully explored. It’s a great one.

As alluded to by other posters upthread, you would have to support the mast stub to prevent fore-and-aft and side-to-side motion while sailing since the hinge alone will not provide any fore-and-aft support and will not provide sufficient side-to-side control to support sailing loads. Either shrouds and an auxiliary forestay and backstay or (if keel stepped) structural support at the deck penetration and a stub section chosen to withstand the substantial cantilever loads. You really need a naval architect for this unless you are open to making your mast into a science experiment.

[Chotu]

Responses in between.

Originally Posted by Jammer

The loads on the hinge pin would be huge as would be the torsional stress on the lower mast segment and the step. If the shrouds are swept back then you will would have to rig a lifting bridle to control lateral movement. The bridle segments would have to terminate at a location in line with the hinge pin but outboard of it as far as is feasible.

This is basically what I was picturing. A set of “mini stays” in 4 directions to hold the TOP of the stub firmly in place. It’s nice because it can tie into a lot of stuff where it’s located. Also very easy to put some eyes, stays and big backing plates down through that deck area which is ridiculously reinforced.

Understood about the lifting bridle. I have a 25ft beam so I have a nice spread for the lifting bridle. That’s a nice way to take up the lateral movement. I can easily put in some pad eyes there in line with the hinge pin.






Generally the gin pole is placed between the base of the forestay and the mast. It need not be at a 90 degree angle and could slope forward (mast down) / downward (mast up) though this will increase some of the stress particularly the tendency for the gin pole to push upwards where it attaches to the mast. The furler should have no effect. Ordinarily the gin pole is removed and stowed at the conclusion of the mast work.

I think I’d go with the 90 degree gin pole. No reason not to. I’ll remove and stow it too. I don’t see doing this process all that often, but what a great feature to have access to inland waters.




As alluded to by other posters upthread, you would have to support the mast stub to prevent fore-and-aft and side-to-side motion while sailing since the hinge alone will not provide any fore-and-aft support and will not provide sufficient side-to-side control to support sailing loads. Either shrouds and an auxiliary forestay and backstay or (if keel stepped) structural support at the deck penetration and a stub section chosen to withstand the substantial cantilever loads. You really need a naval architect for this unless you are open to making your mast into a science experiment.


Or.. no cantilever loads on the stub if it’s stayed at the very top in all 4 directions. I’m thinking that’s the more simple way to do it. A sort of collar around the top (which could even be part of the hinge) that is stayed in all 4 directions of motion. That would effectively be the same as moving the mast stand up 6ft since a stub like that, stayed in every direction, is going nowhere.

No naval architect. This is straightforward. I’m a former scientist who loves tinkering with cool things like this so, bring on the experiment!

[Kelkara]

since you're just moving the boat and mast to a new location ... does the mast really need to go on deck? it's an offshore catamaran, can't you just sling the mast under the bridge-deck between the two hulls?

Pull the boat up to a boat ramp bow in. slide the mast underneath still on it's trailer, then hoist it up off the trailer under the bridge deck. motor off to new location on a calm day. reverse the process at the other end and wash the mast down with fresh water.