I am interested in adding this to my boat but want to know if I can attach the roller fuller to anchor roller ring or have to add a retractable bowsprit to the boat
roller furling asymmetric sail on Catalina MK 28II circa 2003
- Thread starter eberns
- Start date
The key word is clearance. The crane at the masthead needs to move the block forward to clear the top swivel of the existing furler, and attaching the tack to the bow roller would likely put the torsion line too close to the existing sail.
My pole is out 4’ from the top of the roller and The crane is 8” in front of the mast and it’s only just enough.
My pole is out 4’ from the top of the roller and The crane is 8” in front of the mast and it’s only just enough.
@Meriachee nice sprit.
How do you keep the sprit from rising vertically as the sail fills. Is there a bob stay to the bow? (Hidden from view in the image?) I have seen similar sprit‘s but they have a ring fittings that holds them down on the bow.
How do you keep the sprit from rising vertically as the sail fills. Is there a bob stay to the bow? (Hidden from view in the image?) I have seen similar sprit‘s but they have a ring fittings that holds them down on the bow.
I run the same sprit on my Capri 22. I leave the sprit in the retracted position on deck In my experience it doesn't cause too much problem there, although YMMV. It should be noted that Selden does not rate the sprit for a roller-furling sail. These sails have a luff wire or rope, and are flown with more luff tension to get a proper furl. This load exceeds the ratings of the Selden sprit.
Good thing I am not using the Selden sprit. I made mine from 1/4" 6063 that is powder coated. My setup has a Marlow torsion rope on a furler that I built into a top down drum assembly from a Ronstan small boat furler.
All in all, I have a much more tailored unit than the off the shelf offerings and the whole thing probably cost about 1/3 of what a turn key system would have. It goes back to clearance.
Back to the original topic, here's a shot of the crafted crane. It's built from 3/16 boxed 6063 and moves the block forward 8" so the top of the furlers clear each other.
All in all, I have a much more tailored unit than the off the shelf offerings and the whole thing probably cost about 1/3 of what a turn key system would have. It goes back to clearance.
Back to the original topic, here's a shot of the crafted crane. It's built from 3/16 boxed 6063 and moves the block forward 8" so the top of the furlers clear each other.
Here's a better shot of the Selden ring. It's bolted to a custom stainless mount that is attached to the anchor roller plate. There's plenty of clearance from the bow rail, and it puts the tack of the kite firmly on the centerline and way out front. The tack point has been changed to a D ring, as the original design allowed the furler to rotate such that the furling line got tangled.
You can indeed use Selden bowsprit kits for roller furling Sails, both downwind and upwind Sails and spinnaker, and Selden does indeed provide technical guidance. See http://www.seldenmast.com/files/1441613308/595-261-E.pdf
Strictly speaking, Theload on a the sprit from a furling headsail is the same as the load from a non furling headsail of similar design. However, the loads produced by a big upwind headsail (for use in apparent wind angles - awa- between 40and 90, approx) are approximately 2x greater than a down wind asymm (awa between 90 and 150 degrees).
To chose the right sprit, you need to know the approx righting moments - RM - of the boat for pitching and heeling, the dimension of the unsupported length Of the sprit, and the same for the supported length of the sprit. If we don’t know the RM for the boat, we can use info about the length and displacement of the boat to do a conservative estimate.
Selden engineers have done all the analysis and they do indeed provide technical guidance for selecting the correct size sprit for furlong upwind Sails such as Code zeros.
At the upper range for installations,, I.e., for big boats with large righting moments, the limiting factor is the strength of the attachment rings and deck structured, not the sprit per se.
Advanced Technical guidance is available from Selden from US based tech support and some authorized distributors. For very complicated questions, the US team can ask the engineers in Sweden for support.
Judy B
Selden Authorized Distributor
If the anchor roller is strong enough and there’s enough clearance for the new furler, the answer is yes. You’ll also need clearance at the top for the top,swivel on the new furler.
If the bow roller is OEM, you can call the customer support team at Catalina to ask if its strong enough for downwind asymm. Also ask about upwind Asymm as, because those generate more than twice the load as a downwind asymm.
If the anchor roller isn’t OEM, you might need to add structural strength to the roller. consult somebody who has experience doing the upgrade on a variety of boats. Some sailmakers and Riggers have the expertise to do the engineering analysis, but not all.
Don’t forget that the deck to hull joint is part of the structure. That needs to be able to take the strain.
One common problem with attaching a furler to a bow sprit, is that the pulpit gets in the way of pulling the furler straight during fUrling. Possible solutions:
A) add a bow sprit at least 18”long b) remove the top rail on the pulpit or c) if the boat is small enough, mount the furler on the top center of the pulpit rail. Add some bracing or dynema lashing from the top rail down to the stanchion bases and maybe to the ubolt on the bow. That’s a not uncommon trick for adding a free flying furler to a light weight trailerable boat. I’ve done that for a lot of small trailerable pocket cruisers.
Judy
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Oops. This is a C28, not a 22. Please disregard my suggestion about using the pulpit rail! I don’t know how I misread that!