Roller Boom?

[EJO]

OK my old Irwin 32 has a nice heavy duty boom that has a worm gear set-up at the tack'gooseneck end where boom meets mast.
With a slotted handle I can basically rotate the boom indefinitely around it's own axis at the gooseneck.
What is the purpose of this? I of course can only do this when my downhaul is disconnected. My main sheet blocks are connected on the end (clew side) where it can spin around too.
So why this not in-expensive option?
All I can think that maybe this was used to tilt the boom a little to be an extension of the sail plane, but for a cruising sail boat like mine this is overkill. Here are some images of what I'm talking about.

[deniseO30]

in it's day it was "state of the art"? Certainly not single hand friendly, and they were "roller furling" booms as far as I know.

[sailingfool]

That is a roller reefing setup now somewhat of an antique solution.

Use your system to roll up part of the main to effect a reef.

[CalebD]

I've got nearly identical hardware on our boom as well. As Denise noted, in it's day it was an innovative way to reef your main sail. Problem is the sail shape is usually lousy and it must be done by going up to the mast to operate the 'worm gear'.
When it is time to reef we just use the standard slab or jiffy reefing. It may still require a trip to the mast to put in a reef but the resulting sail shape is much better.

[baboon]

This is a roller reefing boom, my boat also has one. It was not meant to furl the whole sail, just to reduce sail area. They never worked great, sail shape is hard to control reefed and because the whole boom rotates you can not attach a permanent vang, which you really would like to use when it blows hard enough to reef.

Most boats including mine have been converted to slab reefing which is easy and safe, especially since it can be done from the cockpit rather than trying to crank the boom at the mast while controlling the halyard.

[svHyLyte]

"Roller Reefing" was first developed in the mid '30's and more or less came into vogue in the early '50s, remaining common up until the mid-60's. For example, Eric and Susan Hiscock had a roller reefing boom on their first "big" yacht, Wanderer III, built of timber by William King's "good men" in the early-50's and upon which they did a 3 year circumnavigation (See "around the World in Wanderer III). Wanderer III continues to sail even to this day while Eric and Susan have sadlylong since both gone to Fiddler's Green.

Whether a roller reefing boom works well or not depends upon a number of factors not the least being the manner in which the luff of the main is led to the aft side of the gooseneck fitting on the boom--normally with a sloped or "ski-jump" track. Eric Hiscock loved the relative ease of the system (also employed later of the 49' Wanderer IV) but the design fell out of favor as it did not permit one to "vang" the boom and, unless the sail was "flat" and the leach hollow cut--or the boom was thickened in the mid-section, the set ofthe sail was poor. One also had no control over outhaul at all so sail shape was badly effected. (This affliction continues to effect "in-boom" furling systems of today which are more costly but frankly no more effective.) If one is not a "racer" and so less concerned about sail shape an efficiency, a roller furling boom coupled with a traveler of good span does have its advantages including, particularly, infinately variable sail area.

FWIW...

[john1066]

My Pearson Vanguard 'Adriana' had a roller reefing boom. They were popular in the 50's and 60's. I converted to a simple slab reefing system.

The two main problems with these mainsail roller reefing systems were the inability to maintain good sail shape, and 'boom droop'. In the latter condition the aft end of the boom droops lower and lower as the sail is rolled, increasing the chances of banging someone on the head.

To improve sail shape you could lay loose battens, or a coil of rope, in the sail as it was rolled increasing the diameter of the bundle at the centre - this worked to some extent.

The main sheet was taken from a rotating plate at the end of the boom, as per the ops picture, and the boomvang used a 'claw', a caliper-like device which gripped the boom and sail bundle. Sophisticated versions had rollers on the ends of the calipers so you could, theoretically, roll the boom whilst the vang was still attached.

I don't think many sailors mourn the passing of this particular innovation.

[CaptainForce]

I have this same roller reefing boom system on my '73 Morgan, but I never use it for those same reasons posted above. Take care and joy, Aythya crew

[SoulVoyage]

My Allied Seawind has the the roller-furling boom. The main reason I don't use it is because I use lazy-jacks.

I guess if I extended the two control lines for the lazy-jacks quite a bit, I would be able wrap up the lazy-jacks with the sail as the boom turned. I keep the bitter ends of the control lines on clam cleats on the mast anyway.

I still have the nice solid bronze handle that came with the roller mechanism.

I'll have to try it out, sometime!

[EJO]

OK Thank you all for the responses. It is what I thought (a reefing system) but I also think that having to unhook your boom-vang and having its loop on the boom (see pic) will not make this a great option.

As for sail shape I would/can still use the cringle-line and Cunningham to keep/put some shape in the sail. Might be an easy system for upwind but I wouldn't use it for down wind with no boom-vang.
Maybe I should use it for storing the main while at port. I'll keep it greased up but will use my regular reef points when I need to reef.