What's the original intended purpose of the triangle plate on the backstay? Is it to bend the mast and flatten the main? OP have mentioned using it to attach the main sheet. Still others have mentioned using it on the lower shrouds as part of a mast-rising system.
O'Day 23-2 triangle plate
- Thread starter ClassicSail
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I think either and other uses.
If it's on the backstay it's likely there is a split backstay below the plate. It could be the boat was built to have two attachments for the backstay for various reasons. Or it could be so that a backstay adjuster can be fitted. In the case of the adjuster if the rig is fractional the mast can be bent to flatten the main which works quite nicely. If it's a masthead boat the mast won't bend much but the adjuster can add tension to the forestay which improves upwind performance in breezier conditions.
If it's on the backstay it's likely there is a split backstay below the plate. It could be the boat was built to have two attachments for the backstay for various reasons. Or it could be so that a backstay adjuster can be fitted. In the case of the adjuster if the rig is fractional the mast can be bent to flatten the main which works quite nicely. If it's a masthead boat the mast won't bend much but the adjuster can add tension to the forestay which improves upwind performance in breezier conditions.
The Triangle plate on the O'DAY 23 (as well as 19, 192, 20, 22, and 222) was to attach the mainsheet, this was pretty much standard on these models from 1975-89. It is located about 12-18" above the backstay chainplate. A previous owner may have switched to a split backstay, but if so, it would be obvious.
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The plate is to allow for a simple backstay adjuster. On a smaller boat, a hydraulic system is not necessary.
Basically the adjuster will have blocks on each leg and a series of blocks to draw the two legs together which effectively shortens the backstay and increases the tension.
Take a look at the various options on the Harken website.
Basically the adjuster will have blocks on each leg and a series of blocks to draw the two legs together which effectively shortens the backstay and increases the tension.
Take a look at the various options on the Harken website.
As a separate issue I don’t like the mainsheet attached to the backstay. I suppose there are advantages but I worry about a wild jybe. Could that take out the backstay and hence the mast. The alternative would be a cockpit sole attachment of the mainsheet to the boom which could cut up the cockpit. Nevertheless, the failure in that system leaves the rig up.
And the sheeting from the backstay doesn’t seem to have a good angle for tight sheeting upwind. I’d much rather the cockpit sole attachment to pull the boom down as well as in. I don’t see the the backstay attachment pulling the boom down very much. But I’ve never sailed on a boat with that system and it might work just fine.
Thinking about it in another way, for the backstay attachment, the tight sheeting angles would probably increase tension in the backstay and possibly improve jib performance upwind.
But I’m unconvinced that backstay mainsheet attachment is a good thing.
It seems ODay liked to abuse their backstays. On the Mariner (the 1st ODay 19), there was a short topping lift wire attached to backstay. Which made it very awkward to raise the main while hove to (or anything not directly into the wind). Many to most Mariner owners install a normal topping lift from the mast head.
The stock Mariner had mid-boom sheeting with the main sheet going to a post at the rear of the centerboard trunk. The main sheet post does divide the cockpit, but gives a designated spot for the helmsman between the main sheet and the tiller. Those who race Mariners invariably change the main sheet to a Crosby rig which gives a pseudo-traveler effect at the transom. The downside of the Crosby rig is to make a boarding ladder at the transom very difficult to use, and the outboard is also awkward to reach. And occasionally on a jibe, the Crosby rig leads to snagging the outboard or the tiller/rudder head with the mainsheet. The Mariner Class Association recently approved the use of a split back stay and back stay adjuster for racing on the theory that the stock off center back stay caused issues on one tack or the other.
Fred W
Stuart Mariner 19 #4133 Sweet P
Yeopim Creek, Albemarle Sound, NC
The stock Mariner had mid-boom sheeting with the main sheet going to a post at the rear of the centerboard trunk. The main sheet post does divide the cockpit, but gives a designated spot for the helmsman between the main sheet and the tiller. Those who race Mariners invariably change the main sheet to a Crosby rig which gives a pseudo-traveler effect at the transom. The downside of the Crosby rig is to make a boarding ladder at the transom very difficult to use, and the outboard is also awkward to reach. And occasionally on a jibe, the Crosby rig leads to snagging the outboard or the tiller/rudder head with the mainsheet. The Mariner Class Association recently approved the use of a split back stay and back stay adjuster for racing on the theory that the stock off center back stay caused issues on one tack or the other.
Fred W
Stuart Mariner 19 #4133 Sweet P
Yeopim Creek, Albemarle Sound, NC
Thanks all for your helpful info. I think the answer from @sunbird22357 is most likely, as I only have a single chain plate at the stern. And there's a bail on the end of the boom where the sheet block could attach.
After two years restoring this boat I’m about ready to launch. I don’t love this mainsheet concept, because of the strain on the backstay (at 20 knots, it's 160 pounds side loading, according to Samson's formula), but I’ll give it a try before making any changes.
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It seems ODay liked to abuse their backstays. On the Mariner (the 1st ODay 19), there was a short topping lift wire attached to backstay. Which made it very awkward to raise the main while hove to (or anything not directly into the wind). Many to most Mariner owners install a normal topping lift from the mast head.
That was the case on a lot of similar-sized boats at the time. Actually, it was not such a bad idea..... just not really a substitute for a "real" topping lift. We had one on our 1970 CAL 21, and used it (CAREFULLY!) for the first 20+ seasons with mostly OK results. However, it was very risky using it solo! With at least 2 person aboard, one person would hoist the sail while the other stood by, ready to release the boom from the "boom-hanger" (that was what O'DAY called it!) as soon as the sail was up, or nearly so. Lowering the sail was the opposite, one person lowered the sail while the other caught the boom and hooked it to the boom-hanger. We mostly raised/lowered the sail at the mooring or anchor, but otherwise, as long as we were headed into the wind (as is best when raising/lowering the sail) it worked. After about 20+ seasons, we finally rigged a true topping lift from the masthead, adjustable at boom end. MUCH BETTER! However, we still used the boom-hanger pigtail to keep the boom centered when the sail was down and furled, that was common practice on many larger sailboats that I have seen too.
The stock Mariner had mid-boom sheeting with the main sheet going to a post at the rear of the centerboard trunk. The main sheet post does divide the cockpit, but gives a designated spot for the helmsman between the main sheet and the tiller. Those who race Mariners invariably change the main sheet to a Crosby rig which gives a pseudo-traveler effect at the transom. The downside of the Crosby rig is to make a boarding ladder at the transom very difficult to use, and the outboard is also awkward to reach. And occasionally on a jibe, the Crosby rig leads to snagging the outboard or the tiller/rudder head with the mainsheet. The Mariner Class Association recently approved the use of a split back stay and back stay adjuster for racing on the theory that the stock off center back stay caused issues on one tack or the other.
Fred W
Stuart Mariner 19 #4133 Sweet P
Yeopim Creek, Albemarle Sound, NC
That off-center backstay gets interesting at times! I recall a few times on our CAL where I actually saw the backstay hanging slightly loose while on a port tack (backstay was offset to starboard on that boat, not much.... but enough to change rig geometry a little!). That was on a beat, when mainsheet tension probably was pulling mast back more than backstay was.
Actually, the original Mainsheet rigging of the Mariner was the "Crosby-style", from 1962-74, that was standard setup. Starting in 1974-5 O'DAY switched to a mid-boom mainsheet on the Mariner, Day Sailer, Javelin, and Rhodes 19. At that time, the 20, 22 (23 was changed in late 1973, or 1974, '74 appears to be last year for the 23-1) also switched from a triangle mainsheet setup across the stern (block near aft end of the cockpit coamings, with a camcleat on one of those blocks and a double-block on the end of the boom, to the Backstay-mounted mainsheet. There are options to improve that backstay-mounted sheet, one is to rig a bridle between two points on the transom, to clear the tiller and move the mainsheet attachment to that. A traveller could be mounted on risers across stern ,again, high enough to clear tiller, or switch to a mid-boom sheet and traveller, that bisects the cockpit.
Personally, I'd be tempted to convert back to the older-style mainsheet like on the pre-1975 boats, that was what we had on our CAL and it worked pretty good for us, although we did not race, so that may have helped. I have never really liked (of course, I admit, I've never sailed a boat with the backstay mounted mainsheet) the fact the the backstay mounted sheet is off-center so in theory, you can sail closer to the wind on one tack than the other. Not eve nsure if I would really notice the difference, but power of suggestion??
No matter what type of mainsheet setup a boat has, a boom-vang is always a GREAT help! With a boom-vang the mainsheet is now mostly pulling the boom and sail in instead of down and in, and that makes a big difference in ease of trimming the main!! I know that I found it much easier to trim the mainsheet on my DS II after adding a boom-vang! It was even a big help on my WIDGEON, which had the Crosby-type mainsheet. The fixed-point (on CB trunk) mid-boom mainsheet on the smaller boats is very hard to get the sail in tight, since as you pull the sail in, there is a point where more downward pull happens than inward pull. That is where a mid-boom traveler gains the advantage of being able to move the lower block to windward allowing the sail to be pulled closer to the center of the boat. At the same time, in heavier winds I have heard (and it makes sense!) that easing the traveller block to leeward gives a bit more "vang effect" to help flatten the sail and depower it (less heeling effect!). The mainsheet attached to the backstay (or a bridle over the tiller) will be able to pull the sail a bit closer to the centerline than a mid-boom sheet will, just because of being farther out on the boom, so same amount of line pulled in results in boom being pulled in more.
O'DAY was not the only builder to use the backstay-mounted mainsheet, and there are THOUSANDS of boats out there using those mainsheets, so they must work and not put undue stress on the rigging. I have heard, as someone else mentioned, that there may be a positive effect from the mainsheet tightening the backstay in higher winds, sort-of an "automatic" backstay adjuster, that would ass tension to the forestay, helping to keep the luff of the jib taut, improving it's efficiency (?), and perhaps slightly bending the mast (at least on fractional rigs) and further flattening the main to depower it in high winds,
I agree about the need to watch the mainsheet on the Crosby setup as you tack, to keep it from fouling the outboard, I experienced that on my Widgeon, I had the outboard clamped right to the transom as O'DAY intended, meaning the motor tilted slightly into the cockpit, but I really liked the simplicty of not needing a mounting bracket! I think on a MARINER, I might opt for a fixed-height outboard bracket to get the motor out away from the mainsheet, since we very, VERY rarely had trouble with the mainsheet fouling our outboard on the CAL which had the outboard on a fixed-height bracket.
The mid-boom setup on my DS II is nice as the mainsheet is forward of where I sit, s oI can keep the mainsheet i none hand and the tiller in the other!
I have scanned and attached a little note from the 1975 O'DAY Brochure about the Mainsheet changes. I suspect these mainsheet chnages were also to reduce costs, but no builder is going to mention that!
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Thank you very much for the additional information and history. I like the Crosby rig, but the mid-boom main sheet is more convenient for cruising. As you point out, the Crosby rig allows better control of the main. And totally agree, regardless of which main sheet arrangement, on the Mariner a boom vang is essential to control the mainsail. Without a vang, it's quite possible to get the boom to hit the back stay on a jibe. Concur that most of the changes in manufacturing over the years were to save money and/or increase sales.
IMO, for single-handed sailing of the Mariner, the stock swiveling jib sheet cam cleats at the aft edge of the cabin, a jib downhaul (or a furling jib), a real topping lift, the boom vang, a tiller extension, and a tiller clutch/tamer are all critical items.
The Mariner Class Association tries to make the rules so that stock boats don't have to make costly modifications to be race competitive. Last year, split back stays were approved, and this year synthetic back stays are allowed. This year also brought in main sail cunninghams. Reports are that with the split back stay there is actually more clearance for the boom swinging. A split back stay is a someday modification for me.
Fred W
Stuart Mariner #4133 Sweet P
Yeopim Creek, Albemarle Sound, NC
IMO, for single-handed sailing of the Mariner, the stock swiveling jib sheet cam cleats at the aft edge of the cabin, a jib downhaul (or a furling jib), a real topping lift, the boom vang, a tiller extension, and a tiller clutch/tamer are all critical items.
The Mariner Class Association tries to make the rules so that stock boats don't have to make costly modifications to be race competitive. Last year, split back stays were approved, and this year synthetic back stays are allowed. This year also brought in main sail cunninghams. Reports are that with the split back stay there is actually more clearance for the boom swinging. A split back stay is a someday modification for me.
Fred W
Stuart Mariner #4133 Sweet P
Yeopim Creek, Albemarle Sound, NC