Advantages of a taller rig/30% larger sail area?

[KP44]

Hi Dockhead,

Most sailing is done in light winds. People focus on storm sails and reefs. I even had a third reef put in my new main. But most sailing seems to be searching for some wind.
My cutter rig is powered by the genoa and balanced with the main. The staysail and single-reefed main balance well in a blow.

[KP44]

Originally Posted by GTom

Speaking of motoring, a lighter boat with smaller rig is definitely an advantage there

Someone mentioned the ICW and mast height.
All the fixed bridges are good for 65' but there is a bridge in Miami area that is 56'. (It's anyone's guess who transposed the numbers.)
So a 60' rig is pretty easy to get through most places. We had to ask or wait at the Freemont Drawbridge in Seattle inside the locks. But it opens every half-hour even during heavy car traffic times.

The waterline length has more to do with motoring than the rig.

[Dockhead]

Originally Posted by KP44

Hi Dockhead,

Most sailing is done in light winds. People focus on storm sails and reefs. I even had a third reef put in my new main. But most sailing seems to be searching for some wind.
My cutter rig is powered by the genoa and balanced with the main. The staysail and single-reefed main balance well in a blow.

Depends on where you sail. Not up here. Look at a wind atlas.

[GTom]

Forgot to mention: Swedish SRS handicap rating for the two boats: "old", short rigged (normal/spi?): 0.853/0.83, "new", tall rigged: 0.881/0.859.

This means an expected speed advantage of 3.4% - at "medium wind speeds" (not reefed?). Doesn't seem different worlds to me...

[valhalla360]

Originally Posted by Dockhead

My mast is one meter too high to get under the bridge between Fehmarn and the German mainland! Requiring quite a long detour to get into the Central Baltic from Kiel Fjord!!

But this is a very rare situation in European waters. We don't have any ICW and very few bridges to deal with, which are not opening bridges. Not really a consideration at all over here.

Sure but he didn't say where he was and lots of members are on the US east coast where it makes a huge difference.

I believe for the US east coast manufacturers that's often the primary consideration in them providing a short and tall mast option.

Same can be said of deep vs shoal draft. In some areas, 10' draft is no big deal but in many areas, 5' starts to be very limiting.

[Dockhead]

Originally Posted by valhalla360

Sure but he didn't say where he was and lots of members are on the US east coast where it makes a huge difference.

I believe for the US east coast manufacturers that's often the primary consideration in them providing a short and tall mast option.

Same can be said of deep vs shoal draft. In some areas, 10' draft is no big deal but in many areas, 5' starts to be very limiting.

Fair enough. Naturally, any specific local constraints need to be taken into account.

[Snowpetrel]

Originally Posted by Dockhead

Not when you're reefed!

The tall rig means reefing earlier, and once you reef your headsail, your ability upwind is gone!

As has been discussed -- each size of rig is best, within its own wind range.

The tall rig is fantastic, up to the upper limit of its wind range. After that, it sucks!

I've gone to windward reasonably well deep reefed many times. Slab reefing the main helps, and having a genoa especially made for furler use is important. Or a staysail/solent that can replace it in stronger winds.

Yes the taller rig is slower in heavy upwind stuff, all being equal but if the tall boat has more ballast or a better ballast ratio it is still likely to get to the windward mark first.

An old salt once said to me that few boats were improved with less ballast, and many were much better with more. I think this applies accurately to older narrower hulls and long keels. And I have talked to owners who have added ballast to the bottom of the keel and say it has transformed the boat.

Average windspeed is something like 11 knots. Maybe 25% of the time we are deep reefed, and of that 25% is dead to windward so this makes about 7% of or so of the time being heavy windward work. Statistically anyway, though I know my average seems much higher...

Even if we said 50% was forward of the beam and 30% was strong winds it's still only 15% or so, the rest of the time the big rig is an advantage or at least not really hurting. And the extra roll moment of inertia may reduce slightly the capsize risk in severe weather.

[Dockhead]

Originally Posted by Snowpetrel

I've gone to windward reasonably well deep reefed many times. Slab reefing the main helps, and having a genoa especially made for furler use is important. Or a staysail/solent that can replace it in stronger winds.

Yes the taller rig is slower in heavy upwind stuff, all being equal but if the tall boat has more ballast or a better ballast ratio it is still likely to get to the windward mark first.

An old salt once said to me that few boats were improved with less ballast, and many were much better with more. I think this applies accurately to older narrower hulls and long keels. And I have talked to owners who have added ballast to the bottom of the keel and say it has transformed the boat.

Average windspeed is something like 11 knots. Maybe 25% of the time we are deep reefed, and of that 25% is dead to windward so this makes about 7% of or so of the time being heavy windward work. Statistically anyway, though I know my average seems much higher...

Even if we said 50% was forward of the beam and 30% was strong winds it's still only 15% or so, the rest of the time the big rig is an advantage or at least not really hurting. And the extra roll moment of inertia may reduce slightly the capsize risk in severe weather.

Just want to point out a couple of facts:

1. APPARENT wind is ahead of the beam more than 50% of the time.

2. Extra "roll moment of inertia" INCREASES, not reduces capsize risk, because the amplitude of rolling is increased. That means you go over further when you roll, if you have more weight aloft, even if it's balanced by more ballast. As someone above pointed out, the motion might be more comfortable for some, in some conditions, but you go over further. And the wild card is resonance, where a slower natural roll frequency increases the risk of matching up with the waves.



When sailing hard on the wind in strong conditions, what kills you is DRAG. Drag makes you heel, slowing you down with weather helm and rudder angle, drag makes leeway, drag counteracts lift. So anything which increases drag is killing you, when you're trying to go upwind in strong weather. On top of that, once you put a roll or two into a roller-reefed headsail, the shape goes to s***. You are right of course that a sail designed for roller reefing, with foam luff, etc., will be better, but I've never met a headsail, foam luff or not, which really worked when hard on the wind with a roll in it. You lose several degrees at least and a lot of speed, as drag spikes up and lift is ruined by the bogus shape you get after furling.

My boat's winter home is in the Solent, which has surely the highest concentration of racing yachts on the planet. You should see me blow by the racing boats with their big rigs, once they've got a roll in their headsails, when going upwind, if they don't manage to change sails. Despite my in-mast furling main (getting back to the original topic ) and bulky, draggy, telephone-pole-like furling mast.

When I was racing years ago, we didn't have roller furling, so I can't speak from first hand experience, but I suppose that if on a windward leg, one boat can keep the roll out of a roller furling headsail (for example by changing down to the right sized sail) while the next, identical boat reefs, it's all over for the second boat.

[TheThunderbird]

Short one

On an old boat never meant to Cruise fast, offshore

Power is in your ballast, not on sails

[TheThunderbird]

"And the extra roll moment of inertia may reduce slightly the capsize risk in severe weather."

Not in my Physics

[Adelie]

Originally Posted by GTom

One of the boats I am considering to purchase come with 2 different rigs from factory: first-generation Malø 40-s are listed with 44m2 SA, the upgraded 40H has 59 m2 while the hull is kept the same, thus the SADR (originally 15.2) got a 30% boost.

How much low-wind speed improvement could we expect from such a boost in SADR?

I am also a bit worried about stability: taller rig undoubtedly moves both the center of effort and gravity higher.

SADR=20 sounds quite extreme to me (we are still speaking of standard layout, no code 0, spi, etc!), shall I see that as an alternative way of a 150% gen or is that a real improvement?

So I ran the numbers thru a formula and my guess is that you can expect to cover an extra 8.25nm/24hr on average when cruising.

Regarding stability. The extra weight aloft cuts both ways. It reduces the righting moment but increases the roll moment of inertia. My takeaway is that when the wind is higher it will cost you a little in speed because you will need to reef earlier in the 40H but your odds of capsizing in braking wave decreases somewhat due to the increased inertia.

The loss of speed in higher winds may seem counter to the increased average speed but what is happening is that the increased sail area is helping boat speed more when the wind is light than the increased mast weight hurts boat speed in heavy winds.

I would go with the taller mast but I would consider adding a removable inner forestay and running backs. Place to set a storm staysail and redundant rigging. I love redundancy for critical components.

[atmartin]

Originally Posted by Snowpetrel

An old salt once said to me that few boats were improved with less ballast, and many were much better with more. I think this applies accurately to older narrower hulls and long keels. And I have talked to owners who have added ballast to the bottom of the keel and say it has transformed the boat.

Adding weight down low will certainly increase the area under the positive stability curve, but it doesn't necessarily improve motion or sea-kindliness:

Originally Posted by Principles of Yacht Design

Most modern designers strive for small gyradii, a light hull, large stability and a small keel. All these features tend to increase accelerations onboard the yacht, thus making it less seakind. For a cruising yacht this is unlikely to be an optimum solution. A very severe problem of this kind was experienced when the first large ships for carrying ore were taken into service. When the ore was loaded on the bottom of the hull, its stability became so large that excessive accelerations were created. In fact, some fatal accidents occurred when people were thrown towards the bulkheads in heavy seas. Modern ore carriers have the ore in a cradle lifted from the bottom of the hull, and much softer motions are obtained.

This doesn't just apply to 'modern' design, but classic, long keel ships and yachts:

Originally Posted by Venturesome Voyages of Captain Voss

If iron or any heavy cargo is put into the lower hold of a vessel till she is down to the loading mark serious consequences may follow. From the quick, jerking roll ensuing and through shipping heavy seas she will most likely get dismasted or break up in the first gale encountered. If too much cargo is put in the between-deck or on deck she is liable to turn turtle. But if the cargo is properly distributed in the lower deck, between-deck and on deck, whatever the case may be, and if then the vessel is handled in the right way, it will be surprising how easy her movements are in heavy gales and large seas.

...

The same principle pertains to small vessel. The TILLIKUM, for example, I had to ballast well down in order to facilitate sailing with a beam wind or when close hauled. The result was that in running, especially with the wind and sea a little on the quarter, she would roll, roll--well, she would roll the teeth out of one's mouth. But as soon as I had placed my four hundred pounds of shifting ballast on the cabin deck, or still better, tied half of it in two bags to the main mast about three or four feet above the deck, she would go along as steady as a lumber-loaded ship. The latter, with their large deck loads, I have found to be the steadiest vessels as far as rolling is concerned.

My shoal draft, long keel, 'traditional' vessel has it's best motion loaded at the start of a cruise: Full tanks and stores, the cockpit footwell crammed with jugs of fresh water and diesel.

Dockhead, I've never been to the Solent, but what kind of racing boat runs a roller-reefed sail? Where I'm at they're either hanked on or, if they've got a furler gear, we change the roller reefed sail out depending on wind strength. Not sure I've ever seen anyone use a roller-reefed jib in a race.

[Dockhead]

Originally Posted by Adelie

. . . Regarding stability. The extra weight aloft cuts both ways. It reduces the righting moment but increases the roll moment of inertia. My takeaway is that when the wind is higher it will cost you a little in speed because you will need to reef earlier in the 40H but your odds of capsizing in braking wave decreases somewhat due to the increased inertia..

You've got this backwards! Increased polar moment of inertia ("roll moment of inertia") increases risk of capsize. We discussed that above.

Extra inertia will not prevent the energy from the breaking wave from being transferred to the boat. No damping takes place due to inertia. More inertia simply reduces the acceleration and the frequency of oscillation. More inertia means the boat will keep going over longer and further after encountering a breaking wave.

The extra weight aloft probably does not cost righting moment -- assuming the tall rig version has extra ballast. If it does not, then the OP should run, not walk away from that one. But most likely it does have extra ballast.

[Dockhead]

Originally Posted by atmartin

Adding weight down low will certainly increase the area under the positive stability curve, but it doesn't necessarily improve motion or sea-kindliness:



This doesn't just apply to 'modern' design, but classic, long keel ships and yachts:



My shoal draft, long keel, 'traditional' vessel has it's best motion loaded at the start of a cruise: Full tanks and stores, the cockpit footwell crammed with jugs of fresh water and diesel.

Dockhead, I've never been to the Solent, but what kind of racing boat runs a roller-reefed sail? Where I'm at they're either hanked on or, if they've got a furler gear, we change the roller reefed sail out depending on wind strength. Not sure I've ever seen anyone use a roller-reefed jib in a race.

Not the serious ones, of course, but the J-Boats, Beneteau Firsts, and so forth, doing club racing, often do have roller furling.

The serious crews will normally have a few jibs on board, but they don't always manage to change them in time.

[double u]

Originally Posted by atmartin

Dockhead, I've never been to the Solent, but what kind of racing boat runs a roller-reefed sail? Where I'm at they're either hanked on or, if they've got a furler gear, we change the roller reefed sail out depending on wind strength. Not sure I've ever seen anyone use a roller-reefed jib in a race.

http://www.newfilmco.com/acmoxph.gif
won the ostar in his time, oldest competitor too:
Phil Weld on Moxie - (rollerfurler sails)...a legend in his time