Schooner vs Ketch

[Don C L]

Originally Posted by Panope

From my past studies of aircraft design:

The two wings of a bi-plane will always negatively affect each other's efficiency. In theory, only infinite space between the wings (gap) will eliminate all interference.

That said, a gap equal to one wing span will be sufficient to eliminate noticable interference. However, the structure needed to support/separate the wings will add more drag (and weight) than is saved by large gaps.

In practice, a gap of approximately 1/4 span is the best workable arrangement (smaller gaps than this will have excessive interference between the wings). It is now well understood that bi-plane aircraft suffer compared to monoplanes in every conceivable way except looking cool (I own a bi-plane )

Now, a split rig (mono-hull) sailboat has its masts set in tandem (staggered) and I am not sure how the above bi-plane info relates (a split rig catamaran has the potential of having its masts set more like a b-plane).

That said, I'll assume that a gap/stagger of one mast height will be needed to eliminate noticeable interference - and that is just not practical.

Note: I altered my boat from schooner to sloop, not for any efficiency gain. Rather, I did it to reduce weight aloft and perhaps most importantly, to get that mast out of the middle of the saloon.

Steve

I have pondered this too... and I am sure you know of the Staggerwing Beechcraft airplane (biplane) whose design reduced the drag without resorting to such a huge gap. Reducing the effect you are describing sounds much like a wing rising out of ground effect, (an effect which does help lift actually)... I am wondering if it isn't more like what we see on the flaps of STOL aircraft where the slot that opens up helps the effect of the flap for lift?

[ScottMeilicke]

I have read staysail schooners came about trying to find a schooner rig that went upwind a bit better. Anyone with experience there?

Chris White took that further by only having jibs in his mast foil schooners.

[Snowpetrel]

http://www.elliott-marine.com/elliot...t/mari-cha-1v/

If you scroll down this link you will find some pretty cool high tech schooners designed by Greg elliot. I also loved the fusion schooner by Nigel Irens.

I was first mate on a 100 foot brigantine and a 140 foot barkentine. These are similar in many ways to a schooner with square sails on the fore. We sailed a 64 foot modern aluminium staysail schooner from Australia to Chile via the sub antarctic islands south of NZ. But I grew up sailing on ketches.

Like all things it is a tradeoff beween schooner and ketch.


Things I like about the schooner.

The mainsail is aft so it is easy to get to. No need to go forward like on a ketch, or lead a heap of lines aft. There is less need to reef the foresail or main staysail until the wether gets really bad. A Staysail schooner with the mainstaysail on a roller would be very easy to work.

The equal height masts give the theoretical ability to have identical fore and main masts and sails. In practice this is not so easy to acheive as the foremast takes the higher headsail loads and the mainmast is harder to properly stay aft and in the middle, unless there is a big gap so a babystay can be used on the mainmast.

The main can easily be set or dropped when at anchor, or even left set for long periods. on the brigantine we occasionally left the main set overnight when at anchor.

A schooner is a fine looking rig, interesting and somehow more shippy and romantic than a ketch.

Lots of ropes and sails to play with, and big sail areas, comprized of lots of smaller, easily managed sails.

Excellant reaching performance.

Easy to balance the helm, it shares this with any split rig. they tend to be more course stable.

Things I dislike about schooners

Harder to properly backstay the foremast, you can run a triatic stay, but this then ties the masts together, and it needs a good fixed backstay on the mainmast. A ketch tends to be a bit easier to backstay as the headsail loads go directly on the mainmast, which is easily backstayed to the middle of the boat. the mizzen doesn't need much backstaying because of it's small size and lack of headsails. Just having swept spreaders normally work fine for the mizzen.

The main needs to be frequently reefed or weather helm can get out of hand pretty quickly. A ketch can easily drop or reef the litte mizzen and it doesn't hurt performance much, wheras a schooner without a main set is a sorry thing in all but very strong winds.

There is no way to blanket that big main for gybing. One of the secrets to the success of a ketch for shorthanded work is the ability to blanket the mainsail behind the mizzen when running downwind to reef or to gybe. this greatly eases the task, as long as you have a good helmsman who can keep the wind in the right spot.

The cost, twice as much of nearly everything really adds up, especially when it comes time to replace the standing rigging. in fairness the ketch also has a lot of rigging, but the mizzen mast is usually pretty small.

Small headsails, the ketch or cutter has much bigger headsails and light air sails.

Windage, and weight aloft two masts will almost alway be worse than one mast in both regards even though they are shorter.

Windage and weight aloft and the poor aspect ratio (AR) results in poorer windward ability. just how much poorer is always up for debate. On the aspect ratio as Panope explained just because individually each sail is high AR doesn't help all that much. it is impossible to get enough of a gap on a normal yacht to avoid interference. so the total aspect ratio of the rig is pretty low. this does give great reaching performance, but hurts windward work.

having a mast so close to my head, this applies to ketches as well. I knew someone who was killed when his mizzen broke and landed on his head. It was pretty horrible, especially for the lady crewing with him. I had (as an obnoxious 16 year old) told him his rigging looked pretty bad and he should replace it (it was stranding in a few places, he was going to change it after one short coastal passage). A few days latter he was dead.

On balance I probably prefer a ketch on technical grounds, but I love the look of a schooner and would be proud to own one. Really there is a smooth transition beween a big mizzen masted ketch and a near equal mast height schooner. A lot depends on mast placement.

In reality though I would just go for a cutter or a sloop, or maybe a little yawl, gaining some of the benefits of a split rigs with minimal cost. But overall it seems the downsides of a split rig and the extra cost of another mast and extra sails just doesn't make sense these days with good winches and high tech gear.

[Pelagic]

Great post snowpetrel and while i am a very happy schooner owner, I agree with your observations

I have sailed on Mari-cha which was quite a thrill, even though she was in cruising mode.

[Snowpetrel]

Pelagic, your schooner looks like an excellant setup for your boat and cruising. Are the fore and main the same? Certainly looks like a very easily handled and low stress rig. Mari-cha 4 looked like a lot of fun and was pretty revolutionary in her day as I rememeber. Here are a few article's about Greg Elliott's designs, including mari cha and the schooners http://www.elliott-marine.com/elliott-library/

Another neat modern schooner I really liked was the plywood ULDB Spencer designed new world.

[Pelagic]

Yes, the fore and aft are exactly the same and with roller furling sails are easily balanced and managed by one.

Attachment 157724

The Aft Mast is only a reaching rig because of the Foremast back stays which run all the way aft to to the cockpit and prevent easing past a broad reach.

I have always wondered about the pros and cons of joining the two mastheads as the Aft mast only has relatively short upper and lower fwd shrouds and a "jumper" stay for stiffness.


With the Fore mast having both the fore stay and staysail stay for support, I wonder if tying in the aft would be better in head seas ?

[Snowpetrel]

Most of the big square riggers I have worked on tied the masts together. It does add another layer of complexity to tuning and calculating rigging loads, But it also adds valuble redundancy and strength.

Ie in your case it would most likely reduce the peak compression load in both masts by spreading some of the headsail loads onto the main, and the better forestaying angle of the mainmast, and it should if tuned properly make the whole rig stiffer overall. But the peak loads on the backstay and forestays would increase in some load cases and if one mast goes over the side the other will likely rapidly follow it.

It is unusual to see a schooner rigged without some form of triatic stay, as much to stop the mainmast falling aft as it is to stop the foremast falling forward. But it sounds like your rig has stood the test of time.

[kristjan]

Old thread however here’s a few vids of schooner sailing.
https://m.youtube.com/channel/UCp5cN...jmywgxQ/videos
I really picked this boat for the deck layout, shoal draft, and I like the interior. Being a schooner wasn’t particularly a strong attraction. I had sailed schooners before, and I liked that this rig matches the boat.
I’ve also sailed several ketches before, and don’t have too strong of a preference.
This boat has only two small winches for jib sheets. I don’t seem to have any problem dealing with sAils etc... the I’ve deliver a few of each rig, and what everyone says is about true. Don’t go to windward great, but it will do it. That’s the price for powerful reaching anywhere from 60 to 140 degrees or so. This hull is long keel for its whole length, so it tracks nicely when doing wing and wing.
This pic is sailing into wolf island, so split the difference and the track is about 60 of wind direction.