Building an in-boom furler

[BOAT]

BOAT you can have that tube if you want to work on a furler.

I think the wind instrument might be a priority, but i dunno, otherwise thanks - I think it might be a component - I have a wind instrument thing that i need you to see first. i will send something.

[mastreb]

There is no question there are sail shape tradeoffs. I don't understand your other two points:

Boom is lower and weight distribution is better - ???
Booms have less reef line clutter - There is very little clutter to the CDI main sail furler. The unfurling line runs along the length of the boom, down the mast and then can be run aft. The furling line runs partially along the boom, down the mast and then can be run aft.

With respect to jamming, this is not a consideration because it's not an in-mast furler. I see very little possibility that the CDI furler can jam.

But the original post was very specific that this furler dramatically complicates trailering, and I just don't have that experience at all.

How do you like the CDI mast-aft furler? My comment about complication is that the mast cannot sit or roll on the cradle in the normal position with the furler in place. How do you handle trailering the mast with the furler on it? (very interested in your technique).

[bobbob]

No issue with that - the mast sits on the console cradle pole fine when trailering. The furler is only attached at the top of the mast (after its disconnected from the boom) and can easily be moved off to the side so the mast sits on the cradle.

I like the furler quite a lot - but I have no other experience to relate it to because my Mac came with it already installed. its a bit stickier to furl/unfurl than the jib furler because the furling lines are doubled back 2-3 times, but it works fairly well. The sail shape is obviously inferior because a)the foot is not attached along the length of the boom, and b)there are no battens so the sail has a negative roach. But because I have nothing to compare it to I can't tell you how much performance is impacted.

[BOAT]

The M boat has a rotating mast. It sort of defeats the whole purpose of that. The performance issue most noticeable would be in acceleration. It would also have an effect in light winds. We all already know that the MAC is an overpowered sail plan (well, the M boat is - I can't really speak for the X boat), thus the cry for furling mains, but this approach is like throwing out the baby with the bathwater.

By eliminating the performance of the rotating mast and the battens you pretty much eliminate the need for furling!

So this becomes yet another way to store the mainsail after it's all said and done. That's not really the most important thing in my mind in regards to main sail management. It's important, but not worth losing all the other things the mainsail is there for in the first place. And I am not even that much of a purist - there are guys out there who scold ME because I am not using a vang! A vang gives you about a 3 to 6 percent improvement in sail shape - imagine what THOSE guys would say to LOSING 20% of sail shape performance for a furler? I get enough reprimands at it is for not having a vang or a bolt rope, but even worse i will not be left in the dust of smaller boats, even a troll has SOME self respect.

It's okay to get the condescending looks out in the ocean from the guys on their Hunters and Catalina's as long as I am passing them up..

[bobbob]

It's not clear to me how this furler defeats the purpose of the M rotating mast - can you elaborate? (I have an X)

I do believe that with vertical battens you can get most of the performance back - however that is purely a hunch on my part.

[BOAT]

The rotating mast presents the luff of the sail to the wind in such a way that the luff is actually part of the foil. On most boats the first 5 or 10% if the luff is wasted as just a place to attach the sail to the mast. The actual working part of the shape can not take effect until the wind can get around the mast and into the sail. A big component of this is having the sail firmly attached to the mast not just on the top and the bottom, but also in the middle and parts in between. Even slugs compromise this and create little mini pockets in the sail. A bolted sail is the most efficient, but only if it is on a mast that rotates out of the way of the sail.

Having a loose luff main makes the whole point of rotating the mast unnecessary. The performance of a bolted sail is already lost, so there is no point to rotate the mast anymore.

[mastreb]

It's okay to get the condescending looks out in the ocean from the guys on their Hunters and Catalina's as long as I am passing them up..

I was sailing the Beneteau cup in San Diego Bay this weekend with a racing coach when we saw a 26M go planing past at full speed. "Man those things look silly powering with a mast like that" as we stewed in 3 knots of wind, wing-on-wing, passing boats with spinnakers because the air was so dead.

All I could think was "He'll be half way to Catalina before we round our mark." Turned out that wasn't an exaggeration: It took us another two hours to round our downwind mark.

Matt

[bobbob]

The rotating mast presents the luff of the sail to the wind in such a way that the luff is actually part of the foil. On most boats the first 5 or 10% if the luff is wasted as just a place to attach the sail to the mast. The actual working part of the shape can not take effect until the wind can get around the mast and into the sail. A big component of this is having the sail firmly attached to the mast not just on the top and the bottom, but also in the middle and parts in between. Even slugs compromise this and create little mini pockets in the sail. A bolted sail is the most efficient, but only if it is on a mast that rotates out of the way of the sail.

Having a loose luff main makes the whole point of rotating the mast unnecessary. The performance of a bolted sail is already lost, so there is no point to rotate the mast anymore.

Got it. Makes total sense. I agree that you would lose this advantage with this furling system.

[BOAT]

From what I can see so far based on what a lot of the major manufactures are doing it appears that a special mast track and a "luff tape" seems to be the best way to move a mainsail up and down a mast without loss of performance. That fact seems to hold true regardless of how the main is stored. It would appear that this "tape" stuff is the best way to go even if your not furling the sail on a boom or otherwise.

I think based on that the first feature that should be considered mandatory on a boom furler project for the M boat would be a "Luff Tape" (Not sure how to do that, but I will investigate it further).

Once I feel I am educated enough on this "luff Tape" stuff I guess i will try to figure out how to get it to 'wind up' on a boom. Seems like it should work

[Highlander]

Roger
Made a boat with an in boom furler can,t remember which one it was now maybe just copy or modify that design

J

[BOAT]

Yes, the inmon furler - might just be the best furler for the boat - we were hoping to come up with something better, but it may very well be that Mikes design may have been the best possible gadget.

[Highlander]

No Boat it was one that Roger designed for one of his older version boats & was an in boom furler .

here,s some reading info might help u
http://www.practical-sailor.com/news/bo ... 036-1.html

J

[BOAT]

I have already read that site about the five major furlers - it's a very good site.

What I have not seen is the in boom furler you are referring to that Roger made for some of his older boats. I would love to see one - is there any info or pictures that you are aware of?

[Jimmyt]

Good article. Lots of great ideas.

My main complaint with my "stock" furler is the rear "bearing" and the aesthetics of the open roll over the stock boom with the hook end. The sail rolls up to the size of my leg. I've got the sunbrella edge which adds bulk (I hope). Job one to a quality in-boom would be getting the rolled sail as small as possible. You shouldn't need the bulky edge if the boom provides the protection. Good bearings would make the operation easier. Having the track line up with the front of the rolled sail is another must-have. Not crazy about adding a track to the mast, but might be ok if light and smooth. The offset mine takes through the alignment balls seems to add a bit of drag. Then, you have to figure out how to keep from tearing up the rig while raising and lowering the mast. I pull my boom, but if I add a mast track to the gen-furler, I've got to be more careful with the mast to keep from wrecking the track.

I think I would like a hinged, or removeable, side to the boom to allow access to the sail if it snarls up.

All that said, I still really enjoy it - just think it could be improved.

[Highlander]

I have already read that site about the five major furlers - it's a very good site.

What I have not seen is the in boom furler you are referring to that Roger made for some of his older boats. I would love to see one - is there any info or pictures that you are aware of?

I believe the whole boom just rotated & the mainsail just wrapped up around the outside of the boom was really a very simple design , ok if u use a boom vang as they r easy to disconnect from the boom , but if u had a rigid vang like I do , u would have to modify the boom brkt so as to be quick draw pin removable & the long leg on the brkt would have to be modified so as it would only a small ear on the brkt so as not too damage the sail when being rolled up on the outside of the boom
this rigid vang is on Beene,s boat is the same as mine


J