I have to have a pedestal made - why not a tabernacle?

[Chotu]

Originally Posted by Corvidae

I did the tiny version of this on a dingy. Scaling up has a few differences. I got away with keeping steel rigging. At cruising cat size, Dyneema is going to be the only option. The stainless rigging on a cat would be a nightmare to handle. You're also going to have to deal with tensioning the rig after raising it, which can be a big chore on a cat, no matter the material.

Once big design flaw I made, that should be avoided. Make your hinge point higher than your head. And for your use case, make sure that total height from the water is 14' or less. That gives you full access to the great loop canal passages.

Thank you for the 14’ controlling height data on the great loop. I was completely unaware of that. I’ll double check everything. I think I’m at 12ft.

[Chotu]

Originally Posted by MicHughV

Chotu,

My advice and recommendation is simple.....hire a crane service. Sorry, I know you don't want to hear this.

You know I always appreciate your input, even if it’s bad news.

But I think we have new information provided by Buzzman that makes this not only possible, but almost easy.

Take a look at the video he posted. It’s amazing. Solves all the problems.

[MicHughV]

Chotu,

There is a very big, big difference between that tiny mast in the video and your 60' stick. Did I say big, I mean BIG!!!

Do yourself a favor, a BIG favor, and hire a crane service. You will be glad you did, once you see the effort it will require to install your mast for the first time, you'll be thinking..." glad I didn't try this on my own"....

[Chotu]

Originally Posted by MicHughV

Chotu,

There is a very big, big difference between that tiny mast in the video and your 60' stick. Did I say big, I mean BIG!!!

Do yourself a favor, a BIG favor, and hire a crane service. You will be glad you did, once you see the effort it will require to install your mast for the first time, you'll be thinking..." glad I didn't try this on my own"....

What?

There is literally NO DIFFERENCE between my mast and that one. Name any difference other than the scale of the components involved in the operation.

I’ve stepped my mast alone multiple times in a 47 foot monohull with a gin pole “crane.” I attached a pic of the crane I used. Single handed.

A remote control toy car and a full size car do the exact same things at different scales. Planes too. We use larger winches and larger running rigging on larger boats. Why do larger versions of things get you so riled up?

[rslifkin]

Originally Posted by Chotu

Thank you for the 14’ controlling height data on the great loop. I was completely unaware of that. I’ll double check everything. I think I’m at 12ft.

On the height thing, assuming you never want to pass under a bridge with less than a foot of clearance, 14 feet is a good target. Being able to clear 15 foot bridges saves you some openings on the ICW and may open a few side trips in places. Realistically, you can go 6 inches higher (14'6" height, 15'6" bridge) and still do the entire Erie Canal.


For the same reason, when I hard top my boat at some point and add a few things like radar, the target is to be no more than 14'6" (preferably closer to 14') with the big VHF antennas lowered.

[Chotu]

Originally Posted by rslifkin

On the height thing, assuming you never want to pass under a bridge with less than a foot of clearance, 14 feet is a good target. Being able to clear 15 foot bridges saves you some openings on the ICW and may open a few side trips in places. Realistically, you can go 6 inches higher (14'6" height, 15'6" bridge) and still do the entire Erie Canal.


For the same reason, when I hard top my boat at some point and add a few things like radar, the target is to be no more than 14'6" (preferably closer to 14') with the big VHF antennas lowered.

That’s exciting stuff! Being able to go on inland trips opens up such an enormous area of cruising, traveling and special relaxing places.

I can even think of several places on the coast that would open up. Great protection against hurricanes, independence from marinas, etc.

I think I can easily keep under the 14’ limit. If I recall, I’m at about 12.

[rslifkin]

Originally Posted by Chotu

That’s exciting stuff! Being able to go on inland trips opens up such an enormous area of cruising, traveling and special relaxing places.

I can even think of several places on the coast that would open up. Great protection against hurricanes, independence from marinas, etc.

I think I can easily keep under the 14’ limit. If I recall, I’m at about 12.

As another thought, for planning significant inland cruising, you'll want to give some thought to things like radar, VHF antennas, etc. Wouldn't want to lose use of those with the mast down.

[Chotu]

Originally Posted by rslifkin

As another thought, for planning significant inland cruising, you'll want to give some thought to things like radar, VHF antennas, etc. Wouldn't want to lose use of those with the mast down.

Good point.

[Corvidae]

The main issue with scaling up is probably going to be mounting hard points. That trapezoid system is going to need 4 mounting points that can handle nearly the same load as the mast step. Put those pivots into a random place on the deck and you're just going to put a hole in your deck. Have to remember when applying leverage that the fulcrum point can be holding several times the actual load, and there's always some **shole that will decide to wake your boat while you're doing it. So lateral stability might be a bigger issue than expected.

[Chotu]

Originally Posted by Corvidae

The main issue with scaling up is probably going to be mounting hard points. That trapezoid system is going to need 4 mounting points that can handle nearly the same load as the mast step. Put those pivots into a random place on the deck and you're just going to put a hole in your deck. Have to remember when applying leverage that the fulcrum point can be holding several times the actual load, and there's always some **shole that will decide to wake your boat while you're doing it. So lateral stability might be a bigger issue than expected.

I don’t doubt that for a minute. I’ve already been thinking up where my reinforcements need to be on deck for the system in the YouTube.

One good thing about this method is i can put it off. It just requires the regular pedestal. I’ll can tinker with this in my “spare time” later

[Patrick of M]

I read this whole thread with as I am also interested in tabernacles. At one point I was considering a deck stepped boat, and looked around alot for information/pictures. In this 60' mast scenario the "secret" seems to be in Australia. Apparently there is an offshore racing community that is bridge bound at 35-40" and many of the boats with 50'+ masts have tabernacles other systems to lower the mast. Finding a picture/information on these boats is another story. I looked around, searched yacht club photos in the area, no one thought to post pictures of their system. I ended up not getting that boat, but imagine if you contact racing clubs the information is out their.
I did contact an engineering company known to design folding mast and associated systems, but they were reasonably reticent to say anything more than "We can do it" without being paid. They seemed quite confident, though would not sign off on old aluminum masts, just new aluminum or composite.
So to the naysayers, it is definitely done, and done underway, just hard to get the info.
P.s. as long as a support with rollers can be positioned close to balance point of the lowered mast, it should be possible to wrangle it into some kind of cruising position.

[Buzzman]

Originally Posted by rslifkin

As another thought, for planning significant inland cruising, you'll want to give some thought to things like radar, VHF antennas, etc. Wouldn't want to lose use of those with the mast down.

An option is to mount them on a targa bar or on the pushpit rail, but they'd still maybe be too high in some places, so having a spring-loaded, rotatable fixture for them - like those trailer manufacturers provide for the jockey wheels on trailers - so it can be pulled out agains the spring, and rotated 90 deg then popped back in again. This would enable you to 'fold' antennas and aerials quickly, but they'd probably still work. Of course, would have to get it made in S/S, or hot-dip galvanised....but...it's a thought...



Also, another point about the canals...what is the narrowest point...??? Never mind the 14' min height, Chotu is building a big, wide, catamaran. What's the maximum width that can get through the narrowest arch, say on the Erie Canal...??

[Buzzman]

Originally Posted by Patrick of M

I read this whole thread with as I am also interested in tabernacles. At one point I was considering a deck stepped boat, and looked around alot for information/pictures. In this 60' mast scenario the "secret" seems to be in Australia. Apparently there is an offshore racing community that is bridge bound at 35-40" and many of the boats with 50'+ masts have tabernacles other systems to lower the mast. Finding a picture/information on these boats is another story. I looked around, searched yacht club photos in the area, no one thought to post pictures of their system. I ended up not getting that boat, but imagine if you contact racing clubs the information is out their.
I did contact an engineering company known to design folding mast and associated systems, but they were reasonably reticent to say anything more than "We can do it" without being paid. They seemed quite confident, though would not sign off on old aluminum masts, just new aluminum or composite.
So to the naysayers, it is definitely done, and done underway, just hard to get the info.
P.s. as long as a support with rollers can be positioned close to balance point of the lowered mast, it should be possible to wrangle it into some kind of cruising position.

I suspect Patrick is referring to Perth, Western Australia, where a road bridge blocks passage for tall masts just before the Perth basin. Probably Royal Perth Yacht Club, South of Perth Yacht Club in Applecross, or Royal Freshwater Bay Yacht Club might be able to assist, if asked.

[rslifkin]

Originally Posted by Buzzman

Also, another point about the canals...what is the narrowest point...??? Never mind the 14' min height, Chotu is building a big, wide, catamaran. What's the maximum width that can get through the narrowest arch, say on the Erie Canal...??

Erie canal beam is limited by the locks, not bridges. If memory serves, max beam is about 42 feet. Even the narrow ditch sections of canal aren't as tiny as some of the European or Canadian canals.

[Buzzman]

Originally Posted by rslifkin

Erie canal beam is limited by the locks, not bridges. If memory serves, max beam is about 42 feet. Even the narrow ditch sections of canal aren't as tiny as some of the European or Canadian canals.

Yes of course, the locks would be the limiting factor. For a shallow draft cat. I know depth is an issue for large monos also.


But 42' ought to be wide enough. How wide is Chotu's catamaran?