Ideal sail plan for 49' performance cat

[olliric]

Hi cat enthusiasts,

I need to double check if my idea of a good sail plan for my boat makes sense. I have sailed mostly on monos and I am not 100% familiar on what works best on cats. I am a performance orientated guy that enjoys playing with running rigging.
This is a long post (hopefully a big thread) but I think it may be quite useful for anyone that is getting a new cat.

Here is the basic data.
Boat design similar to Schionning Wilderness 14:80
Length 15m
Beam 7.6m
Hull length to beam ratio 13.9:1
Hulls draft with dagger boards up .57m
Displacement 9t (fully loaded with live aboard set up, 5 people crew, 1200 liters of W+F)
Mast height 19m, boom 5.5m
Genoa 50m2
Main 75m2

Here are my considerations:
1- Head sail: Due to the restriction imposed by the shrouds which are not very forward, when off the wind (hopefully most time in the tropics) the main sail will be pretty useless except for the roach. The driving force will be mostly from the head sail. That's the reason I don't want a self tacking jib that seems so popular on cats. Also I don't like the sheet angle on self tackers. Pls correct me if I am wrong.
2- I am planning to have 4 sheeting points for the head sails. 2 tracks on the coach roof, one stand up block on the deck at the cabin side near the primary winch and one outboard for the reaching sail. Besides a good size overlapping genoa I would like a much bigger reaching sail. Here is the difficult choice. Heavier cloth screacer on a permanent furler or larger asymmetrical in a sock or asymmetrical on a semi-permanent furler such as rollgen?
3- Symmetrical spi: I am tinkering with the idea that in the future I may want to have a huge kite. Is it really worth and useful? I was thinking of installing 4" removable stand up blocks at the very end of the bows. I would then fly the kite with two control lines only. Is it feasible? What's the best way to handle the beast if wind picks up? the clews fly high...
4- Staysail: Considering that is going to be rather small, is it a good thing to have? Will it be useful?
I could install a stay chain plate at one third of the catwalk and have a halyard coming out from the lower shrouds level. Is it better to have it on a furler or with a removable stay (to be normally parked outboard) and hank-on sail?
5- Boom vang: Due to the shape of the cabin with a close recess around the mast I am thinking of not having any vang to keep the boom up when parked and to stop it from lifting downwind. The main sheet tracks can travel quite a bit out and the shrouds prevent the boom from going out much anyway. I was thinking of having the boom about .30m off the cabin top in parked position.

Cheers

[paulrack]

I have put the following on my soon to be launched boat, it is not a performance boat but I have put a sportier rig on.

- Fathead mainsail with a vang to control the twist. Even with a normal mainsail I could sometimes get an extra knot by tweaking the vang when I was done tweaking the mainsheet.
- Track on coachroof for genoa, plus a block outboard for the genoa when reaching, makes a huge difference to the shape when reaching.
- I have a retractable bowspit with a screacher on a facnor furler. The block is at the aft end of the two hulls.
- An assymetrical spinnaker in a dowsing sock
- You must think about the size of the genoa because when you reef it the shape is not great.
- I also have a storm jib on a removeable inner forestay.

[Woods Designs]

My quick reply is

"What does your designer recommend?"

I haven't used a kicking strap for years

I don't like self tackers either

Not sure why you say the mainsail won't work downwind?? Surely a bigger roached mainsail (compared to a triangular monohull mainsail) blankets a genoa more than a monohull one?

Richard Woods of Woods Designs

www.sailingcatamarans.com

[olliric]

The designer offers kits for the boat construction so it has a basic sail plan. The sails I am interested in are more personal choices.

The kicking strap on monos is very important to avoid depowering downwind. I doubt it matter much on most cats. I hope it does not on mine.

Even when reaching the main can't go out far enough because of the shrouds and the lower part of the sail is stalled. Because of the sail twist the roach does fall out enough to have flow on both sides but it is only a small part of the mainsail area. On the other hand the head sail can be trimmed right from top to bottom. The idea on fast cats is to sail angles and get the apparent wind going forward. If you see ultra performance multies they barely pay out the main. Unfortunately my boat won't be that fast

My quick reply is

"What does your designer recommend?"

I haven't used a kicking strap for years

I don't like self tackers either

Not sure why you say the mainsail won't work downwind?? Surely a bigger roached mainsail (compared to a triangular monohull mainsail) blankets a genoa more than a monohull one?

Richard Woods of Woods Designs

www.sailingcatamarans.com

[dmmbruce]

Are you sure what you intend doing with this boat? If you are going for a large cat as a liveaboard, you are going to need a lot of kit inside it, which all adds weight, and to try and use it as a high performance boat might be extremely unwise. Not to say dangerous with the sort of sail plan that would be needed. Cruising/liveaboard cats are not racing cats. Racing cats are not liveaboard. If you are only going on sheltered waters like the solent, then may be there is overlap, otherwise, beware.

All IMHO of course!

[olliric]

I think we are off the topic a bit but I happy to explain more about the boat.

The cat will be made with epoxy and duflex panels and will be stronger an more seaworthy than most production cats. It will not be a racing cat but it will still be able to sail at wind speed. Around 15m is the minimum length that a cat can deliver a good compromise of performance, seaworthiness and comfort. We have done all the weight and trim calculations and I am confident is not going to be heavier than 9t (at least for the first few years ).
Because of the light displacement, the on the wind sail area is lower than any production cats of the same length. That's the beauty of light and strong cats. Less weight=less power required=less structural stress and strain=greater seaworthyness.
I will not have the space and some of the amenities that some production cats have but I will still have a comfortable lifestyle onboard. Including AC when in a marina.

Are you sure what you intend doing with this boat? If you are going for a large cat as a liveaboard, you are going to need a lot of kit inside it, which all adds weight, and to try and use it as a high performance boat might be extremely unwise. Not to say dangerous with the sort of sail plan that would be needed. Cruising/liveaboard cats are not racing cats. Racing cats are not liveaboard. If you are only going on sheltered waters like the solent, then may be there is overlap, otherwise, beware.

All IMHO of course!

[olliric]

Good to hear that you are soon to launch. I wish I were at the same point
- I don't think I have the space and angle to have a strong enough vang. I could probably have only the space for a spring loaded one to keep the boom up at rest. I am planning to have a removable stand up block attachment outboard just in case I need to control the twist of the main.
- I agree, the more the sheeting points for the headsail the better.
- I'll have a retractable prodder too. However I was hoping to get away with only one reaching headsail. Either screacher or asymmetrical. I assume you then have 4 halyards (staysail, genoa, screacher, asymmetrical).
- I hate the shape of furled genoas. That's why I was thinking of the inner headsail when I need to reduce. I think I have a "hole" between the genoa and the staysail size. Maybe I should get a smaller genoa (jib) but then it is a pain to change out the sail, especially when you need it most.
Do you think your storm jib can be replaced with a working sail?

I have put the following on my soon to be launched boat, it is not a performance boat but I have put a sportier rig on.

- Fathead mainsail with a vang to control the twist. Even with a normal mainsail I could sometimes get an extra knot by tweaking the vang when I was done tweaking the mainsheet.
- Track on coachroof for genoa, plus a block outboard for the genoa when reaching, makes a huge difference to the shape when reaching.
- I have a retractable bowspit with a screacher on a facnor furler. The block is at the aft end of the two hulls.
- An assymetrical spinnaker in a dowsing sock
- You must think about the size of the genoa because when you reef it the shape is not great.
- I also have a storm jib on a removeable inner forestay.

[paulrack]

Your boat does sound fantastic, when are you planning to launch?

- A block is probably a good idea if you do need to control the twist. I know a lot of cats dont have them, and I see Richards comments, my feeling is if you love sailing, ie trying to get the best out of the boat in terms of sail trim it is useful. I guess most boats dont have them probably because of cost, extra complexity or there is not a big enough triangle below the boom.
- To try and get one sail out of an assy and screacher means it will be a compromise, ie you will lose height and depth compared to having the two sails. If you had a screacher you could probably go for a slightly smaller genoa. The challenge with a staysail with a permanent stay is where to attach it so that you can still tack your genoa, supporting the mast where the stay attaches etc. On my monohull I often used to use my racing sails as I hated the furling sail, especially with the canvas UV protector. On my genoa I am using a UV ink instead of designing a nice sail then stitching a whole lot of canvas on the end of it which messes up the shape. That might be something for you to consider.
- I have not looked at seeing if a working sail can be used, I will have to have a look in a weeks time when the rig is up. I will ask Northsails whether they think it is feasible whe we do the test sails.

Cheers
Paul

[olliric]

After 6 months, we have just finished modeling the boat. Now I am building the shed. I hope I can launch 3 years from now. It's a big boat and I am a fussy guy, that makes time a challenge.

- Staysail. It would be cool to have a 3 gear head sails set up, all on furlers. If I can get the staysail to be half the the size of the genoa it should work well when it blows 30+. That would be the set up for long passages. When I am onshore cruising I could secure the furled sail on the side or take it down so I can tack the genoa without problems.

- Reaching sail: I think an asymmetrical is possibly more powerful and more versatile than a screacher. I suspect it is also cheaper. They can be furled just as well. Asymmetrical may not last as much though. Having both will require the 4th halyard (+2 for the main).

Please post you impression after you test your sails.

Cheers

[Woods Designs]

I don't use a kicking strap but I do use a boom vang to hold the boom down when reaching /running. Close reaching I use a long traveller

I don't think a staysail will get much use. I think you will regret relying on a screecher and not having a spinnaker if you plan to do any ocean cruising.

I cannot really comment further without seeing drawings of your boat. I am sure you've seen the article pages of my website where I outline rig design and also sail handling

Richard Woods of Woods Designs

www.sailingcatamarans.com

[olliric]

Hi Richard,

Thanks for the insights. I did read the articles on your website, very interesting.

- Staysail: you are right, the sail will not get much action. Maybe I'll make the chain plate attachment anyway.

- Spinnaker. I was kidding myself thinking of only a furling asymmetrical! I'll get two reaching sails.
Due to the performance orientated design I think I should get a large asymmetrical (much larger than the screecher). It will be harder to gybe but I like the idea of being able to use it in a broader range of wind angles.
I could tack it at the end of the bows for the largest wind angles or at the end of prodder/bowsprit for reaching. The problem I see is that I would have to remove the furled screecher to attach the tack of the assymmetrical. Some people use two attachment on the prodder (one for the screecher and one for the spi) but I think may create chafing issues.

- Here are more details of the geometry of the rig. The boom angle when it touches the shrouds is 50 degrees. The boom touch the shrouds at about 75% of its length. In practice the boom angle will be less due to the curvature of the sail. That's why I was talking about the main not being used completely when reaching and running. Probably half the sail is stalled for angle more than 80 degrees.

Cheers

I don't use a kicking strap but I do use a boom vang to hold the boom down when reaching /running. Close reaching I use a long traveller

I don't think a staysail will get much use. I think you will regret relying on a screecher and not having a spinnaker if you plan to do any ocean cruising.

I cannot really comment further without seeing drawings of your boat. I am sure you've seen the article pages of my website where I outline rig design and also sail handling

Richard Woods of Woods Designs

www.sailingcatamarans.com

[brian eiland]

Hi cat enthusiasts,

I need to double check if my idea of a good sail plan for my boat makes sense. I have sailed mostly on monos and I am not 100% familiar on what works best on cats. I am a performance orientated guy that enjoys playing with running rigging.
This is a long post (hopefully a big thread) but I think it may be quite useful for anyone that is getting a new cat.


Here are my considerations:
1- Head sail: Due to the restriction imposed by the shrouds which are not very forward, when off the wind (hopefully most time in the tropics) the main sail will be pretty useless except for the roach. The driving force will be mostly from the head sail. That's the reason I don't want a self tacking jib that seems so popular on cats. Also I don't like the sheet angle on self tackers. Pls correct me if I am wrong.
2- I am planning to have 4 sheeting points for the head sails. 2 tracks on the coach roof, one stand up block on the deck at the cabin side near the primary winch and one outboard for the reaching sail. Besides a good size overlapping genoa I would like a much bigger reaching sail. Here is the difficult choice. Heavier cloth screacer on a permanent furler or larger asymmetrical in a sock or asymmetrical on a semi-permanent furler such as rollgen?
3- Symmetrical spi: I am tinkering with the idea that in the future I may want to have a huge kite. Is it really worth and useful? I was thinking of installing 4" removable stand up blocks at the very end of the bows. I would then fly the kite with two control lines only. Is it feasible? What's the best way to handle the beast if wind picks up? the clews fly high...
4- Staysail: Considering that is going to be rather small, is it a good thing to have? Will it be useful?
I could install a stay chain plate at one third of the catwalk and have a halyard coming out from the lower shrouds level. Is it better to have it on a furler or with a removable stay (to be normally parked outboard) and hank-on sail?
5- Boom vang: Due to the shape of the cabin with a close recess around the mast I am thinking of not having any vang to keep the boom up when parked and to stop it from lifting downwind. The main sheet tracks can travel quite a bit out and the shrouds prevent the boom from going out much anyway. I was thinking of having the boom about .30m off the cabin top in parked position.

...Staysail. It would be cool to have a 3 gear head sails set up, all on furlers. If I can get the staysail to be half the the size of the genoa it should work well when it blows 30+. That would be the set up for long passages. When I am onshore cruising I could secure the furled sail on the side or take it down so I can tack the genoa without problems.

...I hate the shape of furled genoas. That's why I was thinking of the inner headsail when I need to reduce. I think I have a "hole" between the genoa and the staysail size. Maybe I should get a smaller genoa (jib) but then it is a pain to change out the sail, especially when you need it most.
Do you think your storm jib can be replaced with a working sail?

...Even when reaching the main can't go out far enough because of the shrouds and the lower part of the sail is stalled. Because of the sail twist the roach does fall out enough to have flow on both sides but it is only a small part of the mainsail area. On the other hand the head sail can be trimmed right from top to bottom. The idea on fast cats is to sail angles and get the apparent wind going forward. If you see ultra performance multies they barely pay out the main

....Here are more details of the geometry of the rig. The boom angle when it touches the shrouds is 50 degrees. The boom touch the shrouds at about 75% of its length. In practice the boom angle will be less due to the curvature of the sail. That's why I was talking about the main not being used completely when reaching and running. Probably half the sail is stalled for angle more than 80 degrees.

As I read over a number of your postings I detect some sentiments that I experienced long ago when I sought to eleminate the traditional mainsail and go with a double headsail arrangement....then I added a mizzen onto it so I could use that 'balance' of three sails, and lower my overall height of the rig for multihull application....a single-masted ketch.
www.RunningTideYachts.com

http://www.boatdesign.net/forums/sai...tml#post198605

[olliric]

As I read over a number of your postings I detect some sentiments that I experienced long ago when I sought to eleminate the traditional mainsail and go with a double headsail arrangement....then I added a mizzen onto it so I could use that 'balance' of three sails, and lower my overall height of the rig for multihull application....a single-masted ketch.
www.RunningTideYachts.com

http://www.boatdesign.net/forums/sai...tml#post198605

It seems a versitile sail plan. I am not sure what a mast manufacturer would say. A normal 18m 120square m rig can put about 18 ton compression on the saloon entrance bulkhead. The door entrance can be a problem.
Are you actually building it?

[brian eiland]

Here is the closest relative so far:
http://www.powerandsailing.com/boats...ling-HK40.html

[James Val Jackson]

Hi Richard,

Thanks for the insights. I did read the articles on your website, very interesting.

- Staysail: you are right, the sail will not get much action. Maybe I'll make the chain plate attachment anyway.

- Spinnaker. I was kidding myself thinking of only a furling asymmetrical! I'll get two reaching sails.
Due to the performance orientated design I think I should get a large asymmetrical (much larger than the screecher). It will be harder to gybe but I like the idea of being able to use it in a broader range of wind angles.
I could tack it at the end of the bows for the largest wind angles or at the end of prodder/bowsprit for reaching. The problem I see is that I would have to remove the furled screecher to attach the tack of the assymmetrical. Some people use two attachment on the prodder (one for the screecher and one for the spi) but I think may create chafing issues.

- Here are more details of the geometry of the rig. The boom angle when it touches the shrouds is 50 degrees. The boom touch the shrouds at about 75% of its length. In practice the boom angle will be less due to the curvature of the sail. That's why I was talking about the main not being used completely when reaching and running. Probably half the sail is stalled for angle more than 80 degrees.

Cheers

G'day 'olli', Richard, Paul & Brian + everyone else. Big task there 'ollio' but you sound like you have the 'ticker' to do it & get it 'right'. The biggest task is to get it 'right' the first time around. I think everyone above is far to intelligent for me to make much of a contribution You're all to smart & to young for me to compete. IMHO. That said, I do have a few puzzels though? Why should 14.8 mtrs weight 9T? I don't understand Use 'search engine' & find 'Sundreamer' 57' cat in New Zealand. 20 plus years old, canted hulls (which 99% of the multihull people - do not understand - at all - IMHO) 10,500 lbs (4770kgs) max overall weight. Today could be at or under 4T max. 'dreamer' is not a 'racing' cat by any means. So why so heavy

There are 3 engines that drive a sailing boat - inm the power-development mix - when sailing. The foresail(s), the main, & the slot between them. The 'slot' effect is a significant factor :y) I live in the tropics of the east coast of Australia & have always got much use from a 'properly' & well tuned mail - for it's own power & the extra power of the 'slot'.

At this point - I'll go-away - - shut-up & wait to see if anyone is one the same page, paragraph, sentence.

I am intending to 'cruise' in SE Asia over the next 8 to 10 years & like you need to be able to sail 'well' in very light wind. SE Asia winds are 4 ato 10 kts & 10 kts is rare - when cruising. Efficiency is the only way to think or you'll be motoring for 85% of the time - Gawd forbid -

While I TRUELY wish you well - I think you should - return to the design/concept board. Study your weights VERY carefully!!! Gawd speed, great fortune & enjoy the trip. Ciao, james.

[OkinawaCat]

G'day 'olli', Richard, Paul & Brian + everyone else. Big task there 'ollio' but you sound like you have the 'ticker' to do it & get it 'right'. The biggest task is to get it 'right' the first time around. I think everyone above is far to intelligent for me to make much of a contribution You're all to smart & to young for me to compete. IMHO. That said, I do have a few puzzels though? Why should 14.8 mtrs weight 9T? I don't understand Use 'search engine' & find 'Sundreamer' 57' cat in New Zealand. 20 plus years old, canted hulls (which 99% of the multihull people - do not understand - at all - IMHO) 10,500 lbs (4770kgs) max overall weight. Today could be at or under 4T max. 'dreamer' is not a 'racing' cat by any means. So why so heavy

There are 3 engines that drive a sailing boat - inm the power-development mix - when sailing. The foresail(s), the main, & the slot between them. The 'slot' effect is a significant factor :y) I live in the tropics of the east coast of Australia & have always got much use from a 'properly' & well tuned mail - for it's own power & the extra power of the 'slot'.

At this point - I'll go-away - - shut-up & wait to see if anyone is one the same page, paragraph, sentence.

I am intending to 'cruise' in SE Asia over the next 8 to 10 years & like you need to be able to sail 'well' in very light wind. SE Asia winds are 4 ato 10 kts & 10 kts is rare - when cruising. Efficiency is the only way to think or you'll be motoring for 85% of the time - Gawd forbid -

While I TRUELY wish you well - I think you should - return to the design/concept board. Study your weights VERY carefully!!! Gawd speed, great fortune & enjoy the trip. Ciao, james.

57' 4770kgs? Doesn't seem accurate. My 46' Leopard weighs 18 tons. I saw the scale with my own eyes. A Schionnings G force 46 in all carbon with 2 21hp motors and nothing else weighs in at about 4 tons and that is the lightest cruising cat in that size I have seen anywhere. Think people quote weights all the time and are way off. Including me. I thought my boat weighed 11 tons 13 max with everything on it, then when the crane picked it up 18 tons. Still sails very well though.

[2hulls]

Sorry I'm late to this discussion.

Here are my considerations:
1- Head sail: Due to the restriction imposed by the shrouds which are not very forward, when off the wind (hopefully most time in the tropics) the main sail will be pretty useless except for the roach. The driving force will be mostly from the head sail. That's the reason I don't want a self tacking jib that seems so popular on cats. Also I don't like the sheet angle on self tackers. Pls correct me if I am wrong.

You are definitely not wrong, IMHO. And my shrouds are also swept aft quite a bit. When deep off the wind I prefer to use headsails without the main. I have three to choose from, a big genoa (60 m2), a big Code 0 (1700 ft2), and a big sym spi (150 m2). Last fall on an 8 day passage from Ches Bay to Tortola we didn't raise the main for the first 6 days. It was all DDW 15 to 30 in big surfing seas. We used all three headsails as the wind speed varied. Very comfortable and easy on the boat and crew. Could we have gone faster using the main? Of course. But we weren't racing and wanted and preferred comfort and less work vs top speed. We still managed ~160 nm/day for the passage, even including the last 2 slow days. We arrived rested and without anything broken.

2- Besides a good size overlapping genoa I would like a much bigger reaching sail. Here is the difficult choice. Heavier cloth screacer on a permanent furler or larger asymmetrical in a sock or asymmetrical on a semi-permanent furler such as rollgen?

Agree with having 2 reaching sails. Assuming you'll use a sprit, if you put a permanent furler on it for a large reacher, you'll complicate use of a spi - the permanent furler will make it harder to set up the spi. I chose a Code 0 with removable, continuous line furler. The sails stays stowed until we want to use it - keeping the ***y fabric out of the sun when not in use. The Code 0 excells in wind < 15 on broad reaches and it can be used as a "chicken chute" DDW when it's too windy for a large spi.

3- Symmetrical spi: I am tinkering with the idea that in the future I may want to have a huge kite. Is it really worth and useful? I was thinking of installing 4" removable stand up blocks at the very end of the bows. I would then fly the kite with two control lines only. Is it feasible? What's the best way to handle the beast if wind picks up? the clews fly high...

We like our huge sym spi so much that we bought an identical spare. Both have socks and anytime we're deep off the wind and it's blowing no more than 15 true, a sym spi is what we use. It is a beast to douse if the wind comes up, unless you have extra crew to assist. So would a large asym spi. We've learned a few tricks to help the dousing in higher winds, but it sure is a lot of work. Only downside to a sym spi is that there's nothing you can do to slow the boat to reel in a fish.

Remember that you'll not need a spi pole with a sym spi. This makes flying a sym spi child's play. I routinely set it up and deploy it by myself. "Gybing" doesn't really take place - the sail just floats out front and as the wind varies from side to side you just adjust the guys and sheets and never have to set down your rum.

All of this assumes your boat will not benefit from "tacking" downwind, ala beach cat. Mine won't do it and despite what a lot of people claim, I don't think any real cruising cat can do it. Maybe your's will be able to. Nonetheless, we can carry our sym spis up to 85* apparent if we work at it. If you can and want to tack downwind, an asym spi may suit you better. But for deep downwind tradewind sailing, a sym spi carried alone is golden. That said, I'd like to have an asym spi also. Having a removable Code 0 would allow me to easily tack the asym to the sprit. But gybing an asym spi is WAY more work than a sym spi.

If you choose an asym spi, however, you can rig it as a sym spi tacked to the bows. But you'll need those guys to do this. Otherwise, a sym spi tacked to a sprit doesn't need guys.

4- Staysail: Considering that is going to be rather small, is it a good thing to have? Will it be useful?

I don't have a staysail, but I wish I did. I think it would be very useful for heavy weather if you have to have the apparent wind forward of abeam.

5- Boom vang: Due to the shape of the cabin with a close recess around the mast I am thinking of not having any vang to keep the boom up when parked and to stop it from lifting downwind. The main sheet tracks can travel quite a bit out and the shrouds prevent the boom from going out much anyway. I was thinking of having the boom about .30m off the cabin top in parked position.

Ditch the vang AND the traveler. Check out the dual mainsheet set up on most Catanas. Like switching from mono to multi, once you use one you will never go back. I am astonished that more cruising cats don't use this simple, very effective set up. You will need a topping lift, however.

Good luck,
2 Hulls Dave

[Nordic]

Why not go for an unstayed bi-rig? It gives you low loads, is safe and easy to handle, and minimises wind resistance. A 12 mm wire shroud give you the same wind resistance that a 300 mm wingmast does!!!!

No need for spinnakers, or gennakers etc.

If you want more information, get in touch.

Alan

[downunder]

Consider an A-frame mast as an option as you have time with your build.

http://www.boatdesign.net/forums/boa...g-1999-13.html

http://www.damsl.com/

[brian eiland]

It seems a versitile sail plan. I am not sure what a mast manufacturer would say. A normal 18m 120square m rig can put about 18 ton compression on the saloon entrance bulkhead. The door entrance can be a problem.
Are you actually building it?

You are correct that this rig can interfere with the 'normal' wide open saloon entrance. Creative solutions need to be applied to this mast support situation, ...but be aware that it is not just strickly the mast putting a compression load down onto this bulkhead. Notice that some of this load is offset with the tension load in the 'masthead backstay' that becomes the forestay of the mizzen sail.
http://www.boatdesign.net/forums/sai...tml#post414479

"My masthead backstay then passes over an aft jumper strut that redirects its force down to the base structure supporting the mast.
[IMPORTANT NOTE] This backstay that originates at the masthead DOES NOT reattach to the base of the mast itself, but rather to a structure of the vessel, …and preferably to the structure that accepts the compression loads of the mast to the vessel.]"

I have one gentleman that is considering placing an aftmast rig on his yet to be built Schionning 1320. We are investigating at present.