What is this metal rod for?

[bsurvey]

its a tie rod so you don't pop the deck off and delam the secondary bond between the deck and the transverse deck frame or bulkhead deck support


it is very necessary

[Robin3]

Originally Posted by donradcliffe

Its to keep the halyards from lifting the deck up.

+1 exactly so, give this man a rosette!

[wayne.b]

Originally Posted by GoneIsland

Hello all, I'm perplexed on what the heck this thing is for. I've tried google searches and asking everyone I come across. I'm in the middle of a headliner rebuild and leak hunt on this 1979 Endeavour 37, A plan. It was leaking but I fixed that, now I'm just wondering if I should keep it or take it out and epoxy the hole closed. Someone put time, effort and money to install this but I can't seem to find a use for it.

===

As others have said it is a tie rod to keep the deck from lifting, not so much from halyards, but from bending forces on the hull as the back stay is tightened. It is very important to preserve hull rigidity as mast rigging pressures increase. Otherwise head stay sag will increase as the boat bends, and in extreme cases, actual damage can be done to the hull and deck.

[sanibel sailor]

The halyard load theorists might want to try explaining why it is also found on boats with halyards that end at mast winches. And why they are never found on boats with deck stepped masts and halyards led aft...

It is the standing rigging loads.

[donradcliffe]

While many boats have turning blocks at the deck, the OP's pictures don't show any, so I am changing camps. This boat's tie rod is to hold the deck down from the rigging loads.

BTW the Olson 30 pictured in the thread has been massively reinforced. Back in the days when I flogged the shop boat around (and I raced it really hard, with up to 10 people on the rail), none of the boats had that aluminum arch.

[Boatyarddog]

Originally Posted by Franziska

Clearly a tie rod to deflect mast compression.

www.ladyrover.jimdo.com

Strut Rod, limits deck deflection.


Sent from SV Cloud Duster

[Chuck Hawley]

Originally Posted by sanibel sailor

Called a tie rod, prevents deck lifting/mast driving thru bottom of boat, due to standing rigging stresses, not from halyard loads. Mast in compression, force down thru keel, shrouds pulling up. Boat tries to get narrow and deck lifts at mast hole.

Excellent answer, and also installed so that if the halyards and other control lines bolt to the deck at the base of the mast and turn 90 degrees to come back to the cockpit, the tie rod will counteract this upward force.

Boats where the halyards turn around blocks that are bolted to the bottom of the mast do not have the same loads to counteract.

Chuck Hawley

[TheThunderbird]

Simply... the deck is not designed to match the stress induced by the blocks positioned at the mast base (halyards, reefing lines, others..)

Shrouds are counterbalanced by bulkhead, not the case for those centered lines....

These rods are pretensioned in order to offset any stress on deck (usually intentionally light whatever we size/stuffiness of boat...)

I would seriously disregard any marine technician who hasn't been able to address such a simple issue....

Regards

[rhubstuff]

Sanibel sailor is correct. It is a tension rod to help resist deck lifting.

[leftbrainstuff]

Tension rod. It stops your deck lifting when you apply sheet loads at the base of the mast.

It stops the relative motion between your mast and deck seal which creates a leak path.

Do not remove it or leave it loose. Light tension it with no sheet loads.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[42Possibilities]

[QUOTE=sanibel sailor;2022075]The halyard load theorists might want to try explaining why it is also found on boats with halyards that end at mast winches. And why they are never found on boats with deck stepped masts and halyards led aft...

Not sure I would qualify as a halyard load theorist but…

I think that tie-rods are found on boats with halyards that end at mast winches because of what many others have already stated; to counter the standing rigging stresses. In the case of a boat with a deck stepped mast and halyards led aft, wouldn't the downward force of the mast oppose the lifting force of the halyard blocks? Is it possible that the tie-rod prevents the deck from lifting from both standing rig and halyard tension stresses?

[Frankly]

The static tension in the two caps and 4 intermediates on Cbreeze total to something like 8,000 lbs. Although that does not translate directly to uplift at the deck level I suspect it outweighs a few hundred lbs from a couple of halyard turning blocks. But it would be hard to deny that both contribute to deck lifting with a keel stepped mast. Bottom line don't throw the rod away trying to lighten the ship. Couple of cans of beans and a six pack would be a better bet.

[Dougtiff]

It's a deck tie rod, keeps the deck from trying to raise up in the center, as the chain plates with the rigging under tension is loading up the hull, trying to pull the hull together, harks back to wooden boats, where it was way more of a problem.

[DMBOS]

It is a "panting rod" - rigging tension etc is pulling the beam inwards and forcing the deck upwards and the keel down ( making your hull tall and skinny ) - less beam / more headroom below. The "panting rod" is restricting the headroom and maintaining the beam. ( keeping your hull short and fat )

[Dockhead]

Originally Posted by sanibel sailor

The halyard load theorists might want to try explaining why it is also found on boats with halyards that end at mast winches. And why they are never found on boats with deck stepped masts and halyards led aft...

It is the standing rigging loads.

Ed Zachary.

It's for the buckling loads on the deck imparted by the shrouds.