Anonymous wrote:

* it has a drop keel, not a swing keel.  It's about 350kg and about 2m deep when fully lowered.

So you should be able to get a reasonable idea of what the bottom profile would be like with the keel down. Good.

* the tabernacle (if I've got the terminology correct) consists of a "frame" bolted to the top of the boat into which the mast fits and is held in place with a pin.  As far as I can tell there is no further support under the cabin roof for the tabernacle.  If it's of any use, the mast sits immediately in front of the keel casing.

A lot of stayed masts use a part of the interior as mast support. A bulkhead or post or something so that as the standing rigging pulls the mast down there is something to push up on it as well. While it might be possible to use a stayed mast with a junk rig, it would loose a lot of it's downwind ability or require a head sail to make up for it, similar to the 42ft gazelle junk schooner. However, normally a tabernacle has a part of it go all the way down to the keel for a free standing mast that allows the junk rigged sail  to go abeam or beyond. This requires the mast or tabernacle to go through the deckhead (cabin roof) and attach to the keel. The keel anchors the mast and the partners at the deckhead hold it centred and at the desired fore and aft angle (can be vertical but may slant slightly forward). You do not _have_ to use a tabernacle to have a junk rig but it does allow easier lowering the mast for transport on a trailer boat. It depends on the weight of the mast, if it is light enough you can lift it by hand to vertical and lower it through a hole to the keel, you don't need a tabernacle but really, anything bigger than a dinghy and that starts to get pretty hard.

* as far as balance goes, I'm a very new sailor, so I don't know enough to tell you how it's balanced!  Sometimes I think it has weather helm ... then other times it has lee helm ... all of which is probably because we have our sails arranged very inexpertly!

I'm at the same phase. This summer is supposed to be our learning to sail it as it is summer before I start cutting holes. We've enjoyed playing with the the foresail so far, next is the main and then both together. I suspect we may end up with the same rig still next summer as I get into the planning and parts procuring phase. Or maybe we will run no poles for a season as I have seen three or four other "sailboats" doing. It would be nice to make as much use as we can through this process. It's all very easy to say I will change the rig next year but just as easy for timing to slip. I do have a trailer in the yard I want to get rid of but I am realizing it is probably long enough for long pole transport, so I guess I will keep it for a while yet. It is becoming more apparent that I will be close to solo sailing, so the simplicity of the junk rig is becoming more appealing all the time. Also, getting rid of the shrouds will mean I can even walk on deck to the bow without gymnastics (bad ones at that).

Things seem to have changed as the junk rig has progressed. It used to be that the centre of lateral resistance (CLR) was used and the centre of effort CE or Centre of area CA(more correctly) was placed about 10% of the waterline forward of the CLR. With cambered sails with more "lift" it seems that generally farther forward is recommended, in fact close to the CA of the original sail seems to be the recommendation now. This is more so with a fin keel rather than a long keel. So knowing what the stock CA of the original sail was seems to be more important that the CLR. On my boat, for example, the CA is almost 20% forward of the CLR and from what I have read, it is a well balanced sail rig as is. (several owners seem to agree anyway and I have read no accounts of poor balance)

Anonymous wrote:

We've recently bought a 1985 Gazelle 26, a NZ built trailer sailer.  Here is a good review of it (in fact, I've been told that the boat in this review is the actual one we have!) - https://johncrawfordmarine.com.au/gazelle-26 

Just wondering how feasible it would be to convert to junk rig?  We're in the NT

I was unable to find this boat in some of the normal places I would look for it on line. While the article is interesting, the one thing it does not seem to have is any line drawings.

The normal first step to conversion starts with a "side on" line drawing preferably with the sails drawn in.  This allows calculating the current centre of sail area and the current centre of lateral resistance (actually centre of area for the underwater part of things. It is good (if possible) to also bring any experience you have had sailing with the current rig as to it's balance.

because this is a trailer boat and has a swing keel, it may be hard to get a picture with it lowered. This would make finding the CLR hard. However, getting a picture or even just measuring the sails when raised or as they would be when raised would be easier. This would allow finding the centre of sail area as it is now. So a 90 degree side on picture from as far away as possible but still filling the picture would give a lot of information. Something similar to the second picture in the article you posted but with the head sail on the other side of the mast and with no wind (it could even be on the trailer). Of course if you could find a line drawing with the keel fully extended... that would be wonderful.

Other things to consider. Your current mast sits on top of the cabin with some sort of support under. Because you have a trailer sailor, you are most likely looking at a tabernacle supported mast. The base of the tabernacle will need to go through the cabin/deck to the keel. So consider how much you are willing to disturb your interior to fit a new mast. Because you have a fractional rig now, you may be able to use a SJR with the mast in the same place. If not, an Arne style rig may require moving the mast forward or tilting it forward.

Can your boat be switched to JR? The basic rule seems to be: if it has sails now, a JR will work. The extended answer is: will it make sense in your case. Are you comfortable with cutting a hole in the top of your cabin, with building a tabernacle and it's step, does the required mast placement make the boat less useful to you and your family. Some people do all or most of their sailing alone. For them, it is their boat and a mast in the middle of the Vberth is not a problem. In my case, our boat is the "family cottage by the sea" and so what my wife thinks of any modifications I might make is more important than what kind of rig I sport. I want to replace the rig one way or the other as it is over 50years old. However, whatever I do has to retain the "cottage by the sea" vibe.