Keel-stepped mast foot retainer

[sjconnor]

Hi, I sail Sapphire Star - Olson 34 which is keel stepped. I'm entering a regatta soon and the safety requirements state that keel stepped masts require a retainer at the mast foot.

I definitely dont have one of these on my mast foot, my mast simply sits on the base plate. I guess a retainer is designed so that if there was a rigging failure causing the mast to come down to leeward the retainer would prevent the mast foot from coming off the plate and crashing around inside the cabin if the mast were to come down.

Can anyone please shed some light on this subject. Any other Olson 34's have such a retainer ? Any advice on what approach I might take to fit one ?

Thank you,

Simon.

 

[Loren Beach]

Interesting Question!
I have known of this offshore racing requirement for many years. Since we have never entered our own boat in a Category One event this addition has not been needed.
Our Kenyon spar does indeed sit down in a cast aluminum base, pretty much the same as 98% of the 80's model Ericsons.

Not being a very original thinker, I would first run the question by Buzz Ballenger, http://www.ballengerspars.com/

I believe that I see the problem in three parts:
First you have to pass the inspection/scrutineering for your race.
Second, the solution actually has to work (as opposed to something that might meet the letter of the rule but not the spirit...), and,
Third, it must not be needlessly complex or expensive to build and install.

Sidebar: As a sorta-kinda comparison, the whole "system" for holding down the cabin top against the upward force of the loaded-up turning blocks is a simple length of ss rigging, a turnbuckle, and a T-slot in the mast inside the cabin...

Plan A, (and not labeled by order of importance), might be to run a 12" X half inch ss bolt thru the bilge water passage under the spar floor. and then put a ss wire and short turn buckle at each end that comes up about 18" on the front and back of the spar and ties to a thru-bolt thru that spar. That would tie it firmly to the slot inside the cast step.
No, that's probably not the best idea, but it would work. "Basic brutal engineering"

I will be interested to see what others have done since I would imagine that a number of the mid size and larger Ericsons have entered Cat. One events over the decades.

If any of you have photos, please post 'em!

Regards,
Loren

 

[CSMcKillip]

We have one on our 33

Loren, check your friend with the 33rh, I have one installed on out boat, or what I think is a retainer, it is installed in the cabin roof and runs mid mast in the cabin of our boat, It basiclly keeps the mast in place and held to the cabin deck and mast foot. Ours is a T like base that attaches to the deck top and the T part runs thru the cabin top with a 3/8" hole in the end. There is then two turnbuckels that adjust the tensition on the rig, and a small sliding end that attaches to the mast. very simple solution.

You can see what I am talking about in the photo posted.

 

[Loren Beach]

I bet that it performs the same funcion as the identical short tackle on the rear portion of our spar in the Olson. This balances the up-force on the mast collar/cabin top that gets heavily loaded with halyard turning blocks. In other words, this brings that force back to the spar itself. Some other boats have a casting on top of the cabin that is pinned thru the spar and serves the same purpose.
While the later idea might also keep the base in place (absent the roof flexing upwards), they do not directly lock the base of the mast into the stepping plate or casting.

Note that if my mast or yours were to try to rise, that tackle would do nothing to resist that lifting.

By coincidence, just the other day there was an interior photo on SA showing the massive damage that was done by the mast section inside a boat after a dismasting and destruction of the upper spar.:eek:

 

[CSMcKillip]

I get it, i did see the SA photo, ripped the mast back to starboard a good 5 feet.

 

[CSMcKillip]

So another stupid question, what holds the mast down?

 

[Loren Beach]

what holds the mast down?

Well, in normal usage, you have gravity... assisted by several thousand # of standing-rig tension.

While I have never been present for dismasting involving a keel-stepped rig, I was present (...Present? Heck, I was driving...) for one with a deck-stepped spar, a loooong time ago. This was well off the Washington coast, on a sunny 15 knot afternoon, and no one was hurt. With the broken mast over the side, wandering around with the rolling of the boat, the butt was really trying to do its own wandering but was well-restrained by a plethora of internal halyards at the base. So, I do understand that it's not a good idea to let the base portion turn into "free range aluminum."

Loren

 

[CSMcKillip]

My head must be up my butt right now, holy crap, yep I know that the standing rigging holds the mast, sorry for the brain fart question.

 

[sjconnor]

Yeah I saw that photo on www.sailinganarchy.com, how devastating, in fact it made me think more of this problem. I notice from that picture it also has the turnbuckle attachment to going to the vang and mast-base blocks at the deck.

I guess if one of the shrouds on starboard was to fail then potentially the other two on starboard would keep the mast tied down, but I guess anything could happen. From my recollection the male part of the plate onto which my mast is stepped is not more than half an inch in height so it wouldnt take much for it to be bounced over that.

I can also say Loren I've lost a mast of my own on my previous 24ft boat, sailing solo at night with G&T in hand. Not something I'd like to repeat again regardless of whats in the cup


Rgds,
Simon.

 

[Seth]

Retainer....

Most boats have a deck tie down which is usually a turnbuckle to prevent the deck from lifting up under halyard loads. They are either connected to the mast 18" or so below the deck or down to the mast step...

As for a retainer, the only thing I have seen is a bolt (or 2) which pass through the mast wall and the mast step collar. This is outside of the mast step adjustment bolts-once the mast is seated on the step you pass the bolt through the holes and this keeps in in place.

Anyone?.......