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Old 07-12-2015, 16:47   #16
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Re: Sailboat without rigging.

Something else to think about is that 'sail boats' by nature are not very manourverable. We compromise the manouverablity in order to have free fuel to travel with.

A true motor boat or hybrid would make a lot more sense simply from a practical perspective. And cheap ones are common too.
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Old 08-12-2015, 03:07   #17
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Re: Sailboat without rigging.

Quote:
Originally Posted by Pelagic View Post
Trying to understand what you mean by that?

Without the weight of the mast, sails and rigging aloft, the same sailboat would have a much lower centre of gravity and considerably less windage.

That would make them more difficult to roll..... Unless you meant that they sat broadside in a storm swell with no propulsion?
A sailboat without a mast has a higher static stability, yes. AKA it'll do better in an Inclining Moment test. And in theory, to some degree is more resistant to being rolled. However, the weight of the mast & rigging slows the rolling moment of the boat Greatly. So that without it's spar, a boat hit by a wave has a much more violent motion, & will roll further & faster than if she had her rigging. Thus, when hit by a series of waves, especially if the waves hit the boat with the right frequency, the motion which they set up is amplified by the next wave, until the boat does a 360.

It has to do with various centers of gravity, moments of inertia, & some high dollar engineering terms, which at this hour of the morning, would cause my brain to melt, in trying to recall & explain them.
But basically, it boils down to Polar Moment of Inertia.
- Picture or try spinning a bar with a pair of weights on it close to it's center, & then do the same thing, but with the weights at the bar's ends.
In the latter case, it's much harder to both get it spinning, & to stop it, even though the weight of everything is the same.
And a sailboat without it's rig is akin to the bar with the weights at it's center, vs. a boat with it's rig being like a bar with the weights at the ends.

Or for a different example. Picture 2 cars of the same weight & length, but one being mid-engined, with it's battery near the car's center, & very little body work out towards it's ends.
While care #2 has it's engine & battery way out front, it's fuel tank aft of the rear wheels, & lots of body work (weight) in it's ends.
Car #1 will be quicker to manuver, but also a lot more twitchy. And tougher for an inexperienced driver to control during extreme manuvers. Where as car #2 will be a lot easier to control, but less inherently manuverable.

Try hoisting a heavy anchor, or a couple of full jerry jugs up the rig sometime, & see what it does to your boat's motion. Almost invariably, it slows the speed of your rolling down.

Once, when delivering an 80' schooner, I went up one of the spars to fix something gone awry. And the guys on deck commented on how noticably the rolling of the boat slowed.
This was only with me, 100kg, vs. 50+ tons of boat, with a pair of Massive spars, yardarms, square's, & Lots & lots of rigging... So to lose a rig on a small, round bilged vessel would be Huge by comparison.

Just visually compare the motion of a traditionally rigged tall ship (of size) to that of a racing boat. The spar on the racer will look like a wildly waving fly rod as compared to the spars on the old school vessel... For the reasons sited above. And lacking that weight up high to dampen a boat's rolling, she's more vulnerable to being rolled, when close to her stability limit.
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Old 08-12-2015, 03:54   #18
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Re: Sailboat without rigging.

PS: Put in the simplest terms; picture/experience the motion when onboard a light weight racer, with most of her weight in the keel, vs. the motion in a cruising boat of the same weight, but with a lot of that weight being carried much higher: In the form of; a stouter rig, heavier hull & deck construction, chain in one end, & a dinghy in davits, hung from the stern etc.

Which one has a gentler motion? Both on calm days, & when it's stormy:
Obviously, the latter boat, even though the racer likely has a higher angle of vanishing stability (capsize resistance). But that said, the cruiser would likely be more comfortable in heavy weather, & perhaps even be more resistant to being rolled (ultimately) due to the above explanations.
Look at some of the Westsail's which have survived horrific storms, even after being abandoned by their crews. Such as the one in The Perfect Storm for example.
While a light weight racer's more violent motion isdue to her heavy keel acting as an enhanced pendulum. With there being much less to counter balance it.
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Old 08-12-2015, 05:07   #19
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Re: Sailboat without rigging.

Go for it... Had a neighbor on Tybee Island who pulled the stick on his 33, hung a 15 Honda 4 stroke on an O/B bracket to replace the blown diesel and had a blast. Couldn't get under the local bridge (35') to his preferred local weekend spots and was happy as could be.

Off shore in a beam swell, would be nice to have the canvas up, but the Bristol 26 has a 2400# keel with a 46% ballast/displacement ratio, so in my humble opinion it would probably be at least (if not more so) stable than a displacement trawler hull.

You will need to plan for the inevitable questions, and funny looks though.
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Old 08-12-2015, 05:10   #20
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Re: Sailboat without rigging.

Greetings and welcome aboard the CF, montyp.
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Old 08-12-2015, 05:14   #21
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Re: Sailboat without rigging.

Thanks for trying to explain Uncivilized....
I do have a master mariners license, so I understand a little about stability.

Mono hulled Sailboats already have a lot of reserve stability to compensate for the inclining lever of sails and rig aloft.

So that Metacentric height KM (usually measured from a fixed point on the Keel) is high and roll action without compensating sails is already stiff and fast.

(However a full keel below offers a good dampening feature when rolling)

I agree the same sailboat without the rig, will be stiffer and quicker to snap back from an incline as its metacentric height or reserve stability is even greater as we have lost that weight of rigging aloft.

However dynamic stability above 10 ° of incline is all about hull form and vanishing stability as the centre of gravity rises till it is above the KM and we have negative stability and a good chance to capsize.

Since the hull form is the same, we are now just considering wave period and any other factors that will inhibit righting moments.

There are always a critical synchronicity in beam waves that can enhance a roll, but in a sailboat, they would have to be so close together as to be extremely unlikely.

However, in real survival conditions, sailboats often recover from a knockdown with their masts and rigging in or even under the water. (So heel angle can be greater than 90 to 100°)

In this real scenario condition it is not momentum but "righting resistance" that is the key factor in recovery.

I would suggest that the resistance and weight of the mast and rig below the keel, would have a greater chance of inhibiting and slowing down the recovery, before the next wave completed the roll.

Without the mast, the only inhibiting righting factor is the weight of the water on the Lee side and cockpit.....but that would be the same as with the mast.

Hope this makes sense.
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Old 08-12-2015, 05:59   #22
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Re: Sailboat without rigging.

Consider also resale value. When the time comes that you decide to sell it, no one who wants a sailboat is going to give you much for it, because they'll have to add all of the rigging. And no one who wants a motor boat is going to give you much for it, because... well, a purpose-designed motor boat will be what they're looking for. So, you are either going to have to go to the expense of adding rigging in order to sell it (for which you will probably NOT get your money back), or you are going to have to practically give it away.

Not that that should stop you, if this is what you want. Just something to consider.

Personally, when the time comes that I no longer want to sail, I would probably just get a trawler.
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Old 08-12-2015, 08:58   #23
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Re: Sailboat without rigging.

Quote:
Originally Posted by Pelagic View Post
Thanks for trying to explain Uncivilized....
I do have a master mariners license, so I understand a little about stability.

Mono hulled Sailboats already have a lot of reserve stability to compensate for the inclining lever of sails and rig aloft.

So that Metacentric height KM (usually measured from a fixed point on the Keel) is high and roll action without compensating sails is already stiff and fast.

(However a full keel below offers a good dampening feature when rolling)

I agree the same sailboat without the rig, will be stiffer and quicker to snap back from an incline as its metacentric height or reserve stability is even greater as we have lost that weight of rigging aloft.

However dynamic stability above 10 ° of incline is all about hull form and vanishing stability as the centre of gravity rises till it is above the KM and we have negative stability and a good chance to capsize.

Since the hull form is the same, we are now just considering wave period and any other factors that will inhibit righting moments.

There are always a critical synchronicity in beam waves that can enhance a roll, but in a sailboat, they would have to be so close together as to be extremely unlikely.

However, in real survival conditions, sailboats often recover from a knockdown with their masts and rigging in or even under the water. (So heel angle can be greater than 90 to 100°)

In this real scenario condition it is not momentum but "righting resistance" that is the key factor in recovery.

I would suggest that the resistance and weight of the mast and rig below the keel, would have a greater chance of inhibiting and slowing down the recovery, before the next wave completed the roll.

Without the mast, the only inhibiting righting factor is the weight of the water on the Lee side and cockpit.....but that would be the same as with the mast.

Hope this makes sense.
Yes, what you're saying makes sense. I didn't want to get into using terms like metacentric height, & all of the other ones which go with it. As most likely, less than 1 in 20 members on here have studied that kind of thing. And it's a reach, even for me, as I learned the stuff over 2 decades ago.

Anyway, you should read Fastnet, Force 10 as a lot on the subject of not having a mast, & what happens then, is covered in there (IIRC). It's been a Long time since I read it, but it's a good read. In addition, of course, to being informative.

Having been through a good number of knockdowns to 90 degrees & further, us coming back up was never a real concern. The primary one was to get the boat back onto her feet, & moving smartly along again. Preferably @ a faster speed, so that we had the ability to avoid more situations which might cause us to get knocked over like that again.
Reducing sail was rarely considered, as you need the power & manuverability in order to have a degree of control over things, as opposed to being at the mercy of the waves.
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Old 08-12-2015, 09:14   #24
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Re: Sailboat without rigging.

There is a liveaboard "sailboat" in our marina without any rigging - none. No stanchions/lifelines even. I don't know the owner so can't comment on exactly what is going on but he does motor it over to the pumpout station once in awhile so it does have an engine. It is really not very esthetically pleasing to my eye and does not have many portlights and does not have a raised salon. It must be pretty dark down below. But it must be a relatively cheap apartment. I have never seen it out of the marina but it is probably capable of that. I don't remember an anchor though so probably not something he/she does.
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Old 08-12-2015, 16:54   #25
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Re: Sailboat without rigging.

Let's go back to the OP's question (eventho the OP hasn't been back yet ):

Quote:
Originally Posted by Roadlesstravel View Post
All my water time is in protected waters for the most part.
/
Thoughts on using a solid sailboat as a cruiser and dispensing with the rigging all together? There is are a couple of Bristols - a 26 and a 27 for sale on craigslist.
He's not wanting to cross oceans with it.

I have sailed my current boat w/out mast etc, not an issue at all. Didn't notice her rolling any more than usual. Used to own a 22' way back when, and she was sans rigging for over a year. Not a problem, and no real noticeable difference.

I wouldn't take a sailboat w/out rigging to sea, but even that is not a major issue it seems. Every year, for the big boat shows, we see UK boats coming in sans rigging. With their interior still wrapped in plastic and a tired delivery crew they've managed some pretty choppy crossings to the Netherlands.

Granted, they're usually slightly over 26' but still. And again, not what the OP has in mind.
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Old 11-12-2015, 10:15   #26
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Re: Sailboat without rigging.

Once again; perhaps its just me, but it seems as though many people respond to a post but seemingly have not bothered to read it! I thought the author of the original post made it quite clear that they spent their time in protected waters! they might dash out to fish once in a while, and here I assume, when weather permits. Anyhow I have delivered mastless sailboats on rare occasions and while a bit tender in big wakes etc. they were very manageable. Not roomy enough for me, but "to each his own".
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