Skookum 40 - William Garden Design

[Cheechako]

My advice is dont do things just because they are different. You're making an albatross out of a nice boat. Make a traditional Cutter rig. There are reasons most boats arent done that way!

[nwdiver]

Look at George Buehler’s diesel Ducks, differ center of gravity and they are sail assisted trawlers but they use a mast stepped aft, put in a good lugger diesel and shorter mast and have a sail assisted trawler Garden would have approved.

[Pauls]

It's hard to tell from your drawing, I could not see where the sailplan center of area was marked. However, are you aware that, to have a properly balanced rig, the center of area of the rig needs to lead, ie be ahead, of the center of lateral resistance of the hull? Leads vary for different rigs. Gerr recommends from 13% to 17% of the waterline length for a cutter rig, there are a number of factors that influence what lead you want to use.

Looking at your sketch the rig looks way too far aft to balance. If you haven't yet, I'd suggest you get some books on yacht design and read up on the subject. Dave Gerr's The Nature of Boats is a good place to start.

Good luck on your project.

Paul

[carlhunguss]

with a 110% genoa my center of combine effort as nearest as i can tell is 14" forward of my C.L.R .my water line is 29'. i had planned to reduce the mizzen sail till i got it right . i felt like its only real purpose is to furl the air from the mast and smooth my anchor swing anyway. reducing its size is just a reef to give me an idea . i can do that with old junk sails till i find a balance ? then spend some money on good sails? spending the money to have it a designed seems silly to me . the talent pool here plus my own thought's should be enough ?

[zeehag]

mizzen helps track a boat in heavy air. works great . reduces weather helm a lot. sailed same kinds of wind velocities in sloop and in ketch. i will not cruise sloop again. ketch rocks. cutter was near knock down in lesser winds-- i love ketches. more independence and more time at sea.

[mitiempo]

Z

It's not a ketch though - just a cutter with the mast in the wrong place.

[Pauls]

I believe that your are calculating the sail area by measuring the area of the foresail (genoa). This is not normally how sail C/E is calculated. The norm is to measure the area of the mainsail, and to measure the area of the foretriangle. Foretriangle is used instead of the actual area of the jib, genoa, etc because you are going to be flying different sails up there.

When you calculate things like the balance of a rig it's necessary that you follow the system all the way thru. Values like the percentage lead to use for a rig are intended to apply to a specific approach to measuring the rig. Use another system and they become meaningless.

I'd really recommend you pick up a copy of Gerr's Nature of Boats. It's easy to read, not complicated, and will give you a pretty good understanding about why boats do what they do. It will give you clear and simple instructions on how to design your rig so she'll perform the way you want her to.

Regards, Paul

[Pauls]

One more thing. The purpose of engineering and designing is to predict what something will do WITHOUT building it. That way, if you don't like the result, you can change it on paper, calculate again, and keep changing it until you DO like the result. Then build it.

You can just build something and see what happens, then rebuild it and try again, etc. But it is a LOT cheaper and a LOT faster to do it on paper than it is do it with aluminum, steel and dacron. Give it your best shot at designing something that will do what you really want, and then build it right the first time.

Regards, Paul

[VirtualVagabond]

[QUOTE=carlhunguss;810700]with a 110% genoa my center of combine effort as nearest as i can tell is 14" forward of my C.L.R .my water line is 29'. i had planned to reduce the mizzen sail till i got it right . i felt like its only real purpose is to furl the air from the mast and smooth my anchor swing anyway. reducing its size is just a reef to give me an idea . i can do that with old junk sails till i find a balance ? then spend some money on good sails? spending the money to have it a designed seems silly to me . the talent pool here plus my own thought's should be enough ?[/QUOTE]

You might want to rethink this.

This forum will give you opinions, not designs, and you want to use those opinions as a resource. Fair enough.
So far the opinions here are that the rig is a mistake, so you don't seem to really want to use your chosen resource.

You also said up front that money is short and that is probably why you don't want to get a professional designer involved.
I don't know how the old addage 'penny wise, pound foolish' translates in your part of the world. I strikes me as relevent.
The other reason, and probably the main one, is that a professional designer may want to talk you out of this design, and it's your love child.
Also, you may find that a designer wouldn't want to attach his name to a bad idea if he judges it so.

But you are thinking outside the square and it is making for an interesting thread.

Lastly, in my opinion it would be a pity to turn a boat with beautiful lines into a turkey.

Now that will be 2c, thank you.

[s/v Beth]

Its funny how opinions on the other side of the world and those in your own backyard (my boat is in Bellingham) agree completely. It is true that we are only offering opinions, but sense we are all offering the same opinion, it would probably save you alot of money to listen. (see the thread on Marine truth)

[carlhunguss]

so i have done some more work on this . with the help of some local guys . the lateen /crab claw sail is looking much better . sail cut cad is a fantastic program !!
i would like to take a second to share a few of my thoughts on this .

#1 i as did the designer intend this to be an auxiliary cruiser/motor sailor
#2 i am really more concerned with ease of sailing than performance
#3 not having a boom that is swinging 4ft off the deck is priceless no stays in the walk way either!
#4 i plan to build a flat roof/deck cover over the poop deck
#5 way less rigging and lines i know there is a cutter in the drawing but its a storm jib. i have special plans for that
#6 it looks different with the sails flying higher for a clear line of sight underneath
#7 i cant help but think that maybe i could compromise my reach for upwind
#8 solent would make a killer wing on wing
#9 heavy weather helm only occurs on a reach and is far more acceptable than lee helm in any case for me
#10 the crab claw and lateen dump wind well and are less stress on rigging .
#11 im not worried about resale
#12 center of effort is 3ft lower and has far less weight aloft

[carlhunguss]

any body here familiar with this sail shape? its basically a lateen without the antena and i plan to fly it that way . ive done some reading a little on hoyt and the delta rig runningtideyachts that kinda stuff . i figured i could sail it from the cleats and other creative points till i found a good place to mount the tracks and what not where i felt like they needed to be . im flexible and cant help but think that aspects of this could work . the majority of opinions haven't been full of info . just that its ugly . but i have a thing for the laydies witha few defects . cleft pallet, mini tyrannosaurus rex arm, maybe a club foot midget . they have always had an attitude i like
i would like to pose a question . what would it take to make it work ? phrased that way it would take the conversation in a direction i would like to see it go . if i were to trade excessive weather helm on a reach for running performance or righting moment with less weight aloft that sort of thing how would i need to sail it ? where would it perform best and what tactics could you employ to use this setup at its best . where i live the wind is ether on your nose or at your back . the south puget sound in WA sucks for sailing . lastly THANK YOU ! i do appreciate all of the time you guys are spending on this with me .