Mast hinge at the base?

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Mast hinge at the base?

Postby hahn8 » Mon Jul 09, 2012 9:46 pm

New Daysailer 2 owner. Please forgive me if some of my terminology is inaccurate - I just learned how to sail a month ago. My (non-hinged) mast recently got a dent in it and a slight bend when a gust of wind blew it off the boat as I was unlashing it. It was also a major pain to step even with a buddy helping me. It's still sailable, but I'm looking into ways to repair, or simply get a new mast. But that's another topic. So anyhow, I've been trying to figure out a better way to step without having to cut the mast and installing a tabernacle.

I got an idea and thought I'd get some feedback on it. I was thinking that I could build a hinged plank of plywood with the step casting attached to it. Then fasten the hinge to the keel. Essentially it would be a hinged keel mount step. Next, cut a slot the width of the mast on the cuddy roof from the mast hole to the cuddy opening. Then mount another plank of plywood to the underside of the cuddy roof with a cutout to fit the mast. And finally attach some kind of hardware mount (like a U-bolt) to the plywood that could hold the mast in place.

So if you managed to follow my description, I'm imagining that I could then raise the mast using just the forestay. Once it's into the slot in the cuddy roof, it would pretty easily slide into place. I don't ever plan on sailing in inclement weather, so I'm not all that concerned about waterproofing the cuddy roof, but it'd be easy enough to come up with some way to cover up the slot once the mast was stepped. It seems like this would be the easiest (and cheapest) way to be able to step the mast by myself, which is my goal.

Any thoughts? Am I overlooking something that makes this idea completely ridiculous?
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Postby jdoorly » Tue Jul 10, 2012 12:03 am

I've seen mast slots, similar to your description, on open boats but not cabin or cuddy boats. So, yes the idea has been successfully implemented on some sailboats. There would be questions about retaining structural integrity when cutting a slot in the cuddy roof- well used DS hulls can flex pretty good and cutting a long slot in the deck would certainly promote more flex.

However, there are many people using deck level hinges that are satisfied with their ability to raise the mast singlehanded. I would certainly try that route before cutting fiberglass. Breaking Wind (Scott) has proven it is not hard to repair a cut mast with a sleeve if you change your mind.
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Postby GreenLake » Tue Jul 10, 2012 12:46 am

A deck level hinge conforms to class rules, while I doubt that cutting a slot would be permissible. However, just for the sake of speculation, cutting a slot in the deck is an interesting solution.

My take is, it would require some means of closing it after the mast has been raised. If some kind of overlapping "hatch" could be used that is very firmly clamped to the deck when closed, I wonder whether that might not retain most of the stiffness. So that, in conjunction with some form of under-deck stiffeners it might not be possible to realize such a solution without giving up on sailing characteristics.

It would take a lot of design experience (or trial and error) to get that right.

My boat came with an interesting contraption designed by some previous owner, of which I've made a brief description. [link].
My take is that it gives the best of both worlds. It secures the base of the mast while it's being tilted, so that one person can do it, yet it lets the mast slide down in the vertical position, so that it actually is keel-stepped and loses nothing of its sailing qualities.
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Postby K.C. Walker » Tue Jul 10, 2012 8:38 am

I don't have a DS 2 but a DS 1, however I wonder if the DS 2 also has the rebar reinforcement at the edge of the cuddy? It may be that the DS 2 simply uses the bulkhead at the aft end of the cuddy for stiffness. Regardless, as jdoorly mentioned, this cut would take a considerable amount of stiffness out of the boat and I can't envision a practical way to make up for that. The area you propose to cut out is actually a major structural component. This area resists compression from the shrouds load. The racing guys beef up this area with additional reinforcement to help stiffen the boat.

If you're looking for the cheap way out and you think the hinged tabernacle is expensive, I would reconsider. The tabernacle is a simple installation and works easily. What you propose, unless done extremely well, is likely to ruin the boat and would be considerably more difficult.

By the way, I don't think that your question is ridiculous at all. Asking questions here will almost always get you some feedback and help to think about problems and improvements to your boat.

Welcome to the forum!
KC Walker, DS 1 #7002
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Postby Alan » Tue Jul 10, 2012 1:38 pm

KC,

My 1980 DSII doesn't have any reinforcement material (such as rebar) in the top edge of the cuddy bulkhead. It's thickened in the underside center, but it looks like filler, or filler over glass.

The centerboard downhaul blocks are located in the top center of the bulkhead lip. I just checked Roger Conrad's book; his 1974 DSII has the same rigging as mine.

hahn8,

If your centerboard downhaul blocks are located in the top center of the bulkhead like mine, you would need to cut that mounting point away to make your slot. I'm not sure what you could do to get the downhaul blocks back into a useable position with reliable strength after raising the mast.

On another subject, you mention stepping the mast on the keel. The DSII masts I know about are stepped on the cuddy floor. There's a glassed-in compression post between the cuddy floor and keel. If you actually wanted to step the mast on the keel, you'd have to pass it through the cuddy floor as well as the cuddy roof.

I have a hinged mast, and it works fine. I'm able to raise it single-handed without much trouble, and let's just say I'm not Charles Atlas.:)
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Postby jeadstx » Tue Jul 10, 2012 2:28 pm

I would think that the standard mast hinge available from D&R Marine would be the easiest way to go unless that dent in the mast is high above the deck.
Image
I have no problem putting my mast up by myself using this hinge. I'm also putting the same hinge on my Rhodes 19 since both the DS2 and the R19 have the same mast cross sectional dimensions.

John
1976 Day Sailer II, #8075 - Completed the 2011, 2012, and 2013 Texas 200
1952 Beetle Boat Swan Catboat
Early Rhodes 19
1973 Mariner 2+2, #2607 - Completed 2014, 2015 and 2016 Texas 200
1969 Day Sailer I, #3229
Fleet 135; Canyon Lake, Texas
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Postby hahn8 » Tue Jul 10, 2012 9:39 pm

Wow, I'm floored. Thanks for all the helpful info guys!

jeadstx, thanks for the pic - I haven't seen a fully setup tabernacle hinged mast yet. Is there a lot of play in the mast? That's something that bothers me about my setup - that the mast is pretty loose going into the hole. Was thinking of wedging something in there or creating a plywood mast partner.

KC Walker, I probably overstated the importance of the cost. I'm not really all that concerned about the cost - I view it as part of my learning curve. I just wanted an elegant solution to the stepping problem. The tabernacle looks okay, but it just seems inherently less stable than a one piece mast. Then again, I'm sailing around with a dented mast right now. While there's a bit of play, it seems fine in the 3-5 kt wind speeds I've been practicing in. I guess the tabernacle solution solves several problems for me - I can cut off the dented section which is @ 24" from the base. And it should be relatively less expensive than other solutions - I'd imagine a short 30" section of mast should cost less (unless you have to pay for the stock mast price), esp the shipping.

Alan, I probably used the wrong term. I said "keel-stepped" because that's the term I've heard used for boats with the mast going down to the keel, but I guess it would be more accurate to call it floor-stepped.

GreenLake and jdoorly, regarding the stiffness issue of a cuddy slot, I was thinking that a large piece of plywood bolted to the underside (or topside though asthetically less pleasing) would help in keeping the deck stiff. And I do like GreenLake's hinge. I had thought about something like that also, but then thought maybe it would be easier having the hinge at the floor so that the slot could act as a guide as I raised the mast and it gets more clumsy to handle (esp with a stiff breeze). But this seems to be the best setup if I don't want to cut the mast. I guess I hadn't given much thought to the difficulty of cutting fiberglass. From my Google searching, it's not exactly easy.

While we're on the topic of modifications, has anyone ever attached the forestay higher up to add a larger jib (ie basically turn it into a masthead rig sloop)? I don't know if mine is a standard setup or not, but it's rigged as a fractional sloop. Was there some design reason for the forestay to be attached so low?
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Postby K.C. Walker » Tue Jul 10, 2012 10:28 pm

The main advantage to a keel stepped mast is mast bend control. If you're not taking advantage of this by using an adjustable mast step that pre-bends the mast for sailing conditions, I doubt there's much performance difference between the cut tabernacle and the full-length mast. I have a cut tabernacle mast and I can get a fair amount of bend by using rig tension and a slightly tilted base. I also use a powerful vang at 20:1.

Yes, I have a little bit of slop at the partner but it's never bothered me. The only time I've ever noticed it is when I'm working on the boat, never when I'm sailing. I think a lot of people including myself have sailed in some pretty heavy weather with this setup. After all, it's the shrouds that hold the mast up.

A fractional rig like the DaySailer is a very common dingy set up. I think most centerboard boats are setup this way and keel boats more commonly have mastheads jibs. However, I just added a much bigger jib (gennaker) to my boat. It's actually bigger than the mainsail. It's great for light air but I get overpowered pretty quickly as the wind picks up. I just put up some pictures towards the end of this page http://forum.daysailer.org/forum/viewtopic.ph ... c&start=60 .
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Postby ChrisB » Wed Jul 11, 2012 12:32 pm

hahn8,

I also have a DSII with a "floor stepped" mast and I have always raised the mast by myself. The trick for me has always been to try and point the boat/trailer into the wind when setting up to eliminate side load on the mast while raising. As I get older I've found myself looking at Greenlake's device as a solution for when I'm no longer physically able to lift the mast over the cuddy roof and slide it down through the partner.
Chris B.
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Postby GreenLake » Wed Jul 11, 2012 2:02 pm

What I posted has two components. The "hinged-sleeve" and an "tripod". If I go out often enough (and if I allow myself to be very careful on how I take up the load), I can single-hand with just the sleeve.

If I have extra bodies I have one of them on the cuddy (helping to receive the mast and then lower it onto the mast step with better mechanical advantage than you can do from the cockpit). The other one is behind the boat ("walking" up the the mast to as steep an angle before I do my "weightlifter" thing in the cockpit to get the mast on my shoulder and then pushing it to vertical).

When I feel in shape, I often dispense with help on the cuddy - it's just quicker. When I feel totally out of shape, or when I have any back issues that I want to be careful about, I have the tripod to fall back onto - it takes precious time to set up, but with it, there's almost no strain at all, at least, not more than pulling on a sheet.
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Postby triathjohn » Tue Aug 07, 2012 3:27 pm

hahn8
From what I have read, the jib, which is harder to control especially in strong weather, can be made smaller and the main made larger. this makes sailing and single handing easier. You still have the same amount of sail but it is easier to control. The center of resistance is designed to work with the shifted center of force to keep the boat well balanced. If you were to install a taller jib you may find that you now have more lee helm.
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Postby GreenLake » Tue Aug 07, 2012 6:10 pm

@hahn8,
Leave the basic setup alone, but consider reading up on the UPS Sail. There are several threads here on this site about people's experience with that type of sail.
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