How tight should the tension be on the mast compression turnbuckle of an Oday 35? My deck was pulling down about two inches and I was able to relieve some of the tension when I relaxed all the standing rigging. I wanted to go further but was afraid of finding the ends or the turnbuckle threads. I am pulling the boat for painting in a month and might lift the mast with a crane to gain better access. BUT, how do you gauge the proper tension?
Oday 35 Mast Compression Turnbuckle
- Thread starter Gregg F
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If referring to your standing rigging you need a gauge to get you in the ballpark. You also need to rake the mast and center it. To rake the mast use a halyard with a weight on it. On a calm day the halyard at the deck level should be about 8 inches behind the mast if I remember correctly. Using the same halyard measure to a fixed point on each toe rail and adjust it until the lengths are the same on both sides. Now tighten the turnbuckles snug. Then use a loos gauge and for the diameter of the wire set the tension to the specification. Make sure you tighten both sides equally, meaning take a turn on both sides of the boat so the mast doesn't lean to one side. Once all the rigging is to specs you need to go sailing. One one tack in 12 knots of wind or so see if the rig is loose on the lee side. If it is take a turn on the turnbuckle. Now tack the other way and do the same thing. The rig should not be slack on the lee side in 12 knots of wind, in stronger winds it will be slack. The lowers are smaller diameter wire so they should be a lighter tension than the uppers. Be careful.
The turnbuckle I'm referring to is on the front side of the mast just below the deck. It slips inside a fitting on the forward side of the mast and hooks on the mast collar pulling down on mast partner. I have seen somewhat simlar devices on Catalinas Morgans only they are actually rods that run from the cabin sole to the overhead and apply downward pull to deck. When mine was overtightened the boat had a lot of creaks and groan when underway and I actually had two of my mast wedges fall out onto the floor in the cabin.
Maybe the mast seat?
I'm trying to picture exactly what you are referring to as I have an O'Day 30. My O'Day 30 has a pin that goes thru the mast and rests on two slight depressions in the mast collar on the deck. If your deck is compressing too far with the stays being properly tensioned, there is something else going on. My mast rests on a seat or tabernacle of sorts in the bilge above the keel. This support is open underneath so the bildge water can pass back and forth. I have read other posts where this tabernacle support has become soft therefor not supporting the mast properly. The mast seat or tabernacle that it rests on is soft that could let the mast put too much pressure on the dech when the stay's are tightened. This is just a thought, you may want to check it out.
I'm trying to picture exactly what you are referring to as I have an O'Day 30. My O'Day 30 has a pin that goes thru the mast and rests on two slight depressions in the mast collar on the deck. If your deck is compressing too far with the stays being properly tensioned, there is something else going on. My mast rests on a seat or tabernacle of sorts in the bilge above the keel. This support is open underneath so the bildge water can pass back and forth. I have read other posts where this tabernacle support has become soft therefor not supporting the mast properly. The mast seat or tabernacle that it rests on is soft that could let the mast put too much pressure on the dech when the stay's are tightened. This is just a thought, you may want to check it out.
Do you have your lines from the mast running back to the cockpit? The boats that have what you are describing, have their lines running back. The turning blocks at the mast base on the cabin top create a lot of upward pressure on the cabin top. That rod on the underside of the cabin top counteracts that upward pressure. Yours is most likely an aftermarket item. I don't understand why it is on the forward side of the mast since the turning blocks are normally on the aft side of the mast. A friend of mine just finished re-working his mast collar and moved his to the aft side of the mast. He also added a stainless steel plate around his mast collar to help displace the load to the rest of the cabin top.
Does this help?
Does this help?
OK, we’re getting somewhere. RJMCK3, if you have a 30’ with a set pin in going through the mast then there is no adjustment that can be made to the downward pressure of the mast on the deck. It’s predetermined. DANNY S, if you look at the front side of our mast inside the cabin you’ll see a turnbuckle attached to the mast through a hole and mount and the other end is attached to the mast collar (not visible until you pull your mast). The whole affair is about 12” long. I believe the setting of this device is critical to the standing rig, deck and hull flexing and working together. I may have to get to a rigger that is familiar with this type of set up. I have raised and lowered my mast multiple times in traveling through the Great Lakes and east coast and I think it’s been altered in the process of being handled too many times.
MYSTERY SOLVED! I talked to a rigger and Danny S, you were on the right track. The turnbuckle is there to counteract the tension created when running halyards aft to the cockpit. The proper tension is hand tight when installing the mast. Mine had been overtightened and was caving the deck in.
Thanks for feedback.
Thanks for feedback.
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