Scampi--some high speed lug rig questions

**luomanen** · 24th January 2013, 05:40 AM

Hi everyone. I'm Chris Luomanen. I'm a product designer from San Francisco who has been playing around with a boat design that (sometimes) features a lug rig.

I've sailed dinghies since I was a kid. I've done a little keelboat racing. And I used to sail a Nacra 5.8 on SF Bay--with a big plastic jug zip tied to the mast.

I've been a proa nerd for a long time. I built a land proa called Palindrome, for zooming along the beach. And I built a Dierking Wa'apa with my daughter, which still needs a rig and foils.

I've been doodling proas in CAD for a while, and posting them on The Proafile. My most recent one is sort of a homage to Scamp--called Scampi. Scamp is so cute! And I wondered what kind of proa you might be able to eek out of about the same volume of plywood. Here's that thread.

Proafile Forums | Scampi

Scampi is a 24' long camp-cruising proa with a reasonably sheltered cockpit and a bit of an indoor/outdoor cabin.

I've been flirting with a cambered, or maybe split/cambered junk rig for a long time. James Brett's junk rigged proa is pretty cool. But borrowing from Scamp had me drawing a lug on a proa, and I liked it. It has so many fewer parts. Its maybe not as easy to reef as the junk, but easy. A balanced lug, like a junk, moves my CE forward a bit (kind of a big deal in a proa). And pretty--wow is it pretty.

So now here are the questions.

Assume that I'm going to invest in carbon tubes for my mast and yard (and maybe boom), use low stretch rigging and sail. What do you think is the best strategy for a close winded lug rig? How about one that has to deal with a fast accelerating multihull? Would battens help? I'm fascinated by the conversation going on about adjustability either with a snotter and downhaul or a downhaul and a vang. What's working best? What are your thoughts about aspect ratio? Yard angle? Optimum balance point (how much is there forward of the mast)? Would tweaks like internal halyards help?

Basically, does a lug rig make sense for a micro cruising proa? Or will she be embarrassing to windward--a point of sail proas can often do pretty well at?

Whew, that's enough for now. Sorry for the question bomb.

Thanks in advance for your thoughts.

All the best,
Chris

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**IanHowick** · 31st January 2013, 04:12 PM

That might be getting a bit big for a balanced lug rig? I can see why you're thinking balanced lug for the proa as it's CE is closer to the mast so you don't have to compensate so much when the sail flips around to the other side, but I'm not sure the other issues won't create problems for you.

I like the easy reefing of the lugsail in a lightweight dinghy like the GIS, just point the boat into the wind, drop the rig into the boat, tie in the reefs, re-hoist. The yard helps bring it down and keep everything in the boat as you're blowing backwards hove to on the mizzen.

I don't see that working on the proa, I'm thinking you're going to be hove to with the ama to windward, rig to leeward, so dropping the rig will put everything in the water. The yard will hinder rather than help lowering the rig and getting in a reef. I think I'd rather have a conventional mainsail in a mast track with a big boat slab reefing set-up with tack and clew reefing lines led forward to the gooseneck then down.

The man for bigger high aspect lug rigs is Nigel Irens

His Romilly, Roxane and Roanna seem to push the size and aspect ratios for lugsails beyond what others have done.

He also does high performance multihulls so would be familiar with the issues at that end as well. Given what you're going to spend on a 24 foot boat with a big carbon sparred rig, I'd suggest paying for some of his knowledge would be a good investment. If he expresses excitement/encouragement at what you have in mind, that'd be a good indication you're on to something. Equally, if he doesn't want to touch it at all, that'd be a good indication in the opposite direction.

I assume you're familiar with John Harris's Proa Madness. What you've drawn looks quite similar, just a different concept for the rig?

All the best,

Ian

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