Thanks for the input. I will look into what I can do with the rudder.

I do not have an inboard prop or shaft. I have a 25 hp honda 4 stroke outboard on a hydraulic lift. I have no prop in the water when I sail. :) I think it is cheaper to just trade in an outboard every so often then deal with all the inboard $$$ repairs $$$.  Hopefully I will get a few more years of service out of the engine, or figure out how to move the boat with a yulo. I would like to be engineless, or at the most an electric motor. I really hate dealing with fuel, maintenance, repairs.  Hopefully one day I will be free of the iron sail...

I am a motor head, but marine engines live a hard life. 

From the reports I have read I am not sold on awning fabric for my purpose. If I am going to put so much work into the sail, I need it to last longer then 3-4 years. I am researching uv resistant sailcloth.

I am thinking about this or similar, coated with this or similar. Any suggestions? 

If you used something like that would I still be able to produce a nice sail using the barrel method, or if I am spending that sort of money on cloth to try my best to broad seam? We have an old lockstitch singer 27 clone that is extremely beefy, and I could order a walking foot for it. Would this suffice? I know someone with a sailrite, but I am unsure if they would let me use it. 

Edit: fixed a wrong link

James,

I didn’t see that one coming! I guess you’d better keep the rudder as it is then.

Another detail; does your boat have a fixed 3-blade propeller? When sailing, these do their best to put the brakes on, and also destroy the water-flow over the rudder, behind it. It could be an idea to go for a feathering propeller, one day, but not until you have test-sailed the boat with the new rig.

Any free-standing rudder on the transom should be built to kick up if it hits or catches something.

Arne

PS: After a good night’s sleep, I guess I would still suggest you add an endplate to the rudder, but made as two separate wings. I would just make them of 10-12mm plywood and edge-glue them onto the side of the rudder, about 10cm above the lower edge. If they are hit by something hard, they will just break or be knocked off without damaging the rudder.

James,

I positioned the sail as far forward as I dared, that is with the JR’s CE on the same place as that drawn on the Bm rig. The JR has been drawn with 10% balance, but can easily be shifted forward to 15% or even a bit beyond that, if needed. Normally I have found that when using my cambered panel method, the helm tends to get lighter after the conversion, when close-hauled (if the CE is not moved).

However, all junk sails will produce some weather helm when reaching and running, in particular sloops.

The Rawson 30 is struggling with the keel-hung rudder, which gives a rather sluggish response. On the drawing below I have suggested some improvements. The first I would do (even if I dropped the rig conversion), would be to add that lower corner (magenta) and fit an endplate to prevent the waterflow from escaping under the rudder. Step two would be to add that upper corner (red) as well.

I have also sketched on a transom hung auxiliary rudder, meant for windvane self-steering. You will be surprised to experience how much crisper the response of that rudder is.

Arne

James

I have made myself a string of master sailplans of 7-panel sails, with the AR rising from 1.80 to 2.25. It was quite a job to make them, but from then on, I save a lot of time and brain power by just picking a suitable sail and scaling it up or down. Recently I have gone all-digital, so I can import jpeg drawings of the boat, scale it to the right size and fit one of those sails, and finally trace its profile. In this case, William Garden’s drawing was so good-looking that I didn’t bother with re-tracing it.

My reason for the tall yard is that I want the sail to balance between 5 and 15% with respect to mast. This is to cut as little as possible into the cambered panels. High yard angle = little balance, and vice versa.

The 10° boom rise is to give good clearance when reaching or running. It also gives enough clearance over  the sprayhoods and doghouses, so I don’t need to adjust the topping lifts when reefing the sail. All of the topping lifts on my boats have been made to be standing.

Frankly, I don’t think a schooner rig is practical on the Rawson 30. A sloop is both faster under sail and cheaper to make. Anyway, to make a schooner rig of that size work, you would have to fit a big balanced rudder on the stern to control it. The only time I would aim for a ketch or schooner rig, is if the boat is long, lean, light and tippy, so needs to have a low-set CE (sharpies?).

If you go back to my last posting, you will see that I have added the same sailplan, but now with the Bm rig wiped out. That looks tidier, I think. I am afraid that is how my rigs look: One will either get used to them, or will have to look for something else.

Arne

James,

it is a good thing to be conscious when it comes to structural stress. However, I don’t think you need to worry that your boat will be damaged if you make that hole in the deck. Remember, most sailboats has been given a king plank in the deck to take the horrible compression from the Bermuda rig  -  which does its best to bend the boat into big bananas.

The forces on the mast step and partners of a freestanding mast are mostly sideways, and a lot lower than in a Bm rig. Take a look at Ingeborg’s partners, (aluminium) below.

Think of it as a chainplate. The forces needed to heel the boat over is about the same as those working on the chainplates of a stayed rig. Have you ever seen chainplates that have been bolted with 6-8 bolts, like that? Remember, a grp deck like this can take an enormous amount of side-forces. I have plonked freestanding masts through the deck of a number of production boats, and there has never been any problems.

Of course, if the space for a mast step has already been taken, then it is not an alternative, but I think you should have another look before you drop it. Installing a mast step will be messy anyway. Converting a boat to a new rig is like climbing or rounding a row of obstacles.

Mast height.
Have you decided on a sail area, yet? I just checked. A 50sqm Johanna-type sail with SA= 50sqm and AR=2.10 would need a mast with a LAP=11.2m or a total mast length of around 12.7m. That is about a foot lower than the Bm mast.

Cheers, Arne

PS:
Something like this. If lowered to AR=2.0 the area is about 47sqm and the 40' mast can be used.