De Masting creates better standing rigging with "New larger Fractional rig" Questions

[RiverPirate]

My American Mariner 8.0 lost its mast in June 2011...The demasting happened relatively with minimal damage to property or life, and no injuries requiring any medical attention. The upper port shroud cables failed at the swage point above the hardware that attached to my port chain plate. Then pressure from the winds simply swept the original mast out from under itself starboard, as the top mast went one way the bottom blew out the other side to port. Tearing out the mast deck attachment plate, and bending some stanchions.

Needless to say sailing hasn't been very much fun this past year or so since the demasting. We are ready to step the newer, upgraded, & slightly taller and larger over all fractionally rigged mast & its new slightly larger, better attached foot print.

I found a used mast in Oklahoma and had it shipped to me with a total cost of $700.00 I could not find a local replacement anywhere near this price.

I took advantage of providing some much needed updates like a new boom kicker, a boomvang, along with some deck organizing hardware. Now all 3 mast halyards end in the cockpit.

Before it was pretty crazy trying to get it all going single handling. I also added a simple but effective RayMarine autopilot system to assist me with tiller management, when I do need to go forward for any sail or rig tuning.

Here's where I have been stuck.

The boat the newer mast came off was a 1969 Cal 29. Its a little over 2 feet taller overall.

I wanted this to slightly raise height position overall boom for a future rear hardtop Bimini , for a newer “bridged” traveler system.

I was able to exchange some track hardware on my mainsail for my old mast sail feed system.

As I am a self trained sailor, something on the new mast has been bothering me so much so I am compelled to not move forward until its explained better to me, and such resolved!

The spreaders on the cal 29 mast are literally "Lose”, is that normal? I'm not sure what to make of it, they literally flop horizontally approx 2-3 inches fore & aft, in the hardware that attaches them to the mast? I have never seen a system such as this. I’m not sure how to figure it into the “New” standing rigging measurements for my ordering needs, with the spreaders in this configuration. My old American 8.0 shrouds, and stays were 25+ years old, the older boat was an upgrade from a Tanzer 16 I learned on. I have had NO LUCK finding any local PortlandOregon or VancouverWashington "Rigging" experts to talk with & perhaps take a look at the project or even pictures of it, and perhaps give some experienced expert advice to this wannabe novice sailor, before the family budget runs out on this old boat project. Any assistance would be most fondly appreciated from any sailors out there experienced with rigging or re-rigging or upgrading spars on a boat.

Thanks in advance....Al

[tenchiki]

My current (trailerable) boat has swinging spreaders. Searunner Trimarans were spec'd to have swinging spreaders, too. Swinging fore-n-aft is fine - the idea is that the spreader will shift to line up with the load. Any vertical movement is a problem, as it could allow the spreader to get out of column, and then "bye bye mast" again.

[roverhi]

Spreaders do not need to be fixed in the fore and aft plane. Under load with a shroud on them, they will self align. As long as the movement in the spreaders is not the result of wear in the attaching pins or flexing of the mounting hardware, it's fine.

[gjordan]

I hope you beefed up your chainplates to take the new higher loads?___Grant.

[RiverPirate]

Why yes we did address the chain plates with much fan fare. The new ones should do well for what we use the boat for. Thanks for your post! Al

[Andrew Troup]

Swinging spreaders (for in-line rigging, strictly) are IMO a good way of avoiding the high stresses you can otherwise get at the roots of the spreaders, a common failure point.

The only bad thing about them (although mast companies tend to dislike them on principle, I personally think they're stuck in the 'swept spreader' mindset) is that the cap shrouds will swing about on the leeward side when they inevitably come slack due to the loaded, windward capshrouds stretching. Sometimes they'll get into quite a rhythm if the boat is pitching at some multiple of the natural frequency of swing.

Particularly on a boat which covers the miles, this can eventually cause failure where the wire meets the swage, usually at the bottom rigging screw. You can avoid this possibility by either fitting something resilient at the mast to bias the spreader forward, or perhaps fit a stretchy cord further down, to pull the cap shroud towards the forward lower when it goes slack. You'd want to do this in such a way it doesn't cause a localised problem for the wire, either with poultice corrosion or with kinking.

BTW: Remember to raise the spreader tips before clamping them to the shroud enough that they bisect the angles of the shroud they deflect.

[RiverPirate]

Thanks for the great expert sail rigging advice & the specific woes for me to pay extra attention to. I'm pretty sure now I understand exactly what you meant! Which surprises me alot, as I am self taught "beginner" sailor and its been a long 30 year haul to get this far in my sailing experiences, but the sailing nomenclature and my own collective understanding are beginning to make sense. I will be extra vigilant in getting those shrouds set up right!
Best regards, Al Cady

[RiverPirate]

Does anybody have any sort of special calculation on getting the correct size and type of SS cable to complete this project. I am referring to all the standing rigging, fore and aft stays and both sets of the upper & lower port and starboard shroud sets.

I am ready to order a reel of cable from Eriggingsupply, as they are the best source I have found eyt. And lastly. Any thoughts on how the spreaders connect to the upper shroud. I removed the original cable and know what that looked like. But that technology was 30+ years ago, perhaps there has been advances in cable strength and lessons learned since then.....

[Andrew Troup]

Without a lot more information no-one is going to be able to make any recommendations (and if they did you'd obviously not be wanting to rely on free advice of unknown quality)

For instance, are your main chainplates abeam of the mast ("inline" rig) or aft of the mast ("Swept spreaders")? *
Presumably there's just a single pair of spreaders?
What's your displacement? Righting Moment? Maximum sail area under plain sail? (or preferably, the luff and foot dimensions of the mainsail and foretriangles)

Omce you've gathered this info, and decided what sort of margin of safety is appropriate for the conditions and rigging life you aspire to, you will either need to visit a decent library and get a book or two to study up on rig calculations, or talk to someone with verifiable qualifications to advise on wire size.

Clamping of the shrouds in the spreader tip is not rocket science and good practice is the same as it was decades ago: if it can be clamped in such a way that the wire is not damaged, and the spreader will not slip if someone heavy stands a foot out from the mast, you're good to go. The other desirable characteristic is that it does not present snag or chafe points to the mainsail when the boom is squared outboard.

You do need to make sure the tip of the spreader is raised so that it bisects the angles of the heavily loaded (ie cap) shroud. They should NOT be level, as is seen quite commonly on marinas these days.

*If you have swept spreaders, the spreaders and more particularly the spreader roots must be engineered specifically for that situation, and in particular must NOT have any fore and aft play. The spreader roots need to be much stronger and more carefully designed for a swept spreader rig, because they feed considerable force into the midheight of the rig to push it forward.
However you seem to have forward lowers, which suggests your chainplates are not set up for swept spreaders.