Heavy sailboats are slower and

[Hoodsail]

Attachment 198863GPS speed was 6.1 knots, on beam reach, in 15knots (true) wind. unfortunately GPS is at the helm and couldnt get it in the pic (see attached - will need to zoom into read wind instruments over companionway). No main just about 70% unfurled of genoa (120%) driving her (admittedly the headsail does most of the work on the Bristol 35.5). Maybe 0.5 knot current in my favor. Sooo, point being, just cause your heavy (displacement 15,000#) doesnt make you slow...sorry for the upside down image.

[Cheechako]

Generally, a heavy boat will move as fast (nautical miles per hour) as a light one, given enough sail area up. Negating an ultra light surfing. (speed determined by the waterline length) BUT a light boat will accelerate to that speed faster! In real light airs there is not enough wind pressure to move a heavy boat up to speed well.
SO racing you want a boat to accelerate to speed and stay there.
Cruising in the trade winds it matters less.

[Dockhead]

Originally Posted by Hoodsail

Attachment 198863GPS speed was 6.1 knots, on beam reach, in 15knots (true) wind. unfortunately GPS is at the helm and couldnt get it in the pic (see attached - will need to zoom into read wind instruments over companionway). No main just about 70% unfurled of genoa (120%) driving her (admittedly the headsail does most of the work on the Bristol 35.5). Maybe 0.5 knot current in my favor. Sooo, point being, just cause your heavy (displacement 15,000#) doesnt make you slow...sorry for the upside down image.

So 5.6 knots on a beam reach in 15 knots if wind, is not SLOW?


I'm not really sure what to say about that except -- YMMV.

[Dockhead]

Originally Posted by Cheechako

Generally, a heavy boat will move as fast (nautical miles per hour) as a light one, given enough sail area up. Negating an ultra light surfing. (speed determined by the waterline length) BUT a light boat will accelerate to that speed faster! In real light airs there is not enough wind pressure to move a heavy boat up to speed well.
SO racing you want a boat to accelerate to speed and stay there.
Cruising in the trade winds it matters less.

"Given enough sail area" -- so, if the SA/D is the same.


That is more or less true, but the trick is getting SA/D the same. More sail area requires more righting moment. How do you get it on a heavier boat? There's no way without doing something which will slow the boat down.


To put it another way -- imagine the opposite case. Take a boat and make it lighter. Leave everything else the same. The SA/D INCREASES and you automatically have enough righting moment for the same sail area if you leave the ballast and keel alone. If you want to leave the SA/D the same, you can pare down the keel and make it into a more hydrodynamically efficient shape.

[Hoodsail]

Dockhead, come on - "YMMV" - "your mileage may vary?" - you must mean when you have a 100hp yanmar, pushing over 44,000# - it certainly will. You should have seen in my photo that the genoa was about 25-30% furled and no main working so yep...5.6 knots with a theoretical hull speed of approx 7 knots is moving along...respectfully yours...THE ROCKET

[a64pilot]

Originally Posted by JPA Cate

We have a friend, with an easily driven boat, who, now, post 70 yrs. age, prefers to sail on the 10-15 forecasts, and when possible, use the Code Zero. It is that this wind range offers the flattest seas, and the best boat speeds, and extremely easy conditions.

Ann

I’m not 70, nor do I have an easily driven boat, but I also prefer those kinds of winds, at 15 kts on a beam reach I will sail at 7.5 kts, which is pretty much as fast as my boat goes, higher winds just means bigger seas to us.
With the code zero, I can still sail close to 7.5 kts with a 10 kt wind, but I’m happy with anything over 6, we are cruising and don’t want to be laid over on our ear taking water over the bow, that’s fun to some, but not us.

Now that I have Retired and we are full time. We wait until we get those forecasts, but I’ll also admit to motoring on occasion when the sea state is calm, but we have a week of sporty weather coming.

I still smile over all these arguments, when the difference in fast and slow is 2 kts.

[Dockhead]

Originally Posted by Hoodsail

Dockhead, come on - "YMMV" - "your mileage may vary?" - you must mean when you have a 100hp yanmar, pushing over 44,000# - it certainly will. You should have seen in my photo that the genoa was about 25-30% furled and no main working so yep...5.6 knots with a theoretical hull speed of approx 7 knots is moving along...respectfully yours...THE ROCKET

Well, I don't know. I've been sailing all my life, and I never had a boat which couldn't make hull speed in 15 knots on a beam reach, and not by any means were all of my boats "fast".

[Dockhead]

Originally Posted by a64pilot

I’m not 70, nor do I have an easily driven boat, but I also prefer those kinds of winds, at 15 kts on a beam reach I will sail at 7.5 kts, which is pretty much as fast as my boat goes, higher winds just means bigger seas to us.
With the code zero, I can still sail close to 7.5 kts with a 10 kt wind, but I’m happy with anything over 6, we are cruising and don’t want to be laid over on our ear taking water over the bow, that’s fun to some, but not us.

Now that I have Retired and we are full time. We wait until we get those forecasts, but I’ll also admit to motoring on occasion when the sea state is calm, but we have a week of sporty weather coming.

I still smile over all these arguments, when the difference in fast and slow is 2 kts.

Well, 2 knots more than 5.5 knots is 36%. 5.5 knots and 7.5 knots is totally different. It means 180 miles a day instead of 132 miles.





And yes, like you, I also like a beam reach in 15 knots. Who the hell doesn't?



I have been loving the Baltic this summer, which unlike my usual stomping grounds in the Northern parts of the Atlantic Ocean, has been serving up balmy sunny days and Force 4's and flat seas day after day after day. I'm starting to forget what a F8 is like.



I might even need to break out the Big Jib.

[wingssail]

Originally Posted by Dockhead

Well, I don't know. I've been sailing all my life, and I never had a boat which couldn't make hull speed in 15 knots on a beam reach, and not by any means were all of my boats "fast".

Well, if he rolled up his genoa further he could be even slower.

On the other hand, on a beam reach, using the mainsail and a full genoa, if the boat did not become overpowered, he might be better able to hit hull speed.

[Don C L]

Originally Posted by Dockhead

Well, I don't know. I've been sailing all my life, and I never had a boat which couldn't make hull speed in 15 knots on a beam reach, and not by any means were all of my boats "fast".

In fact that is probably the most practical and accurate way to figure out what the true hull speed is of any non-planing boat!

[Adelie]

Originally Posted by agpilot88

Question:


This is the way I understand it. The heavier the boat, the more stable and slower it is and the lighter the boat the quickler and less stable it is?


Correct?


Of course take into consideration of the draft and the shape of the hull. Seems like price and weight corresponse with each other.


Lee

Boat speed is directly influenced by 2 things
Boat length
Sail area to Displacement.

More boat length “helps” speed because the resistance starts spiking at a certain speed that is related to boat length and beam. This is HullSpeed. Longer boats tend to be narrower for their length and so a bit less affected. Multihulls are extremely narrow for their length and gain considerably from this.

SailArea to displacement is like power to weight for cars. A heavier car isn’t necessarily slow if you put a bigger engine in it. A mustang is a lot heavier than a Civic but is still faster because the engine is proportionately bigger.

With boats other things like hull shape and surface condition and sail shape and rig type come into play but the 2 biggest factors are length and SA/D.

Edit: At very low wind speeds in flat water sail area to wetted surface area (SA/WA) is the dominant factor in speed. Length has essentially no effect. SA/D is a reasonable proxy for SA/WA but not perfect.

[wingssail]

Originally Posted by JPA Cate

We have a friend, with an easily driven boat, who, now, post 70 yrs. age, prefers to sail on the 10-15 forecasts, and when possible, use the Code Zero. It is that this wind range offers the flattest seas, and the best boat speeds, and extremely easy conditions.

Ann

10-15 is fine. 12-25 is better. We are both over 70, and our boat is not particularly easily driven (old IOR, I think you know the type), but here in our part of Mexico the sailing is stunning. Good winds, flat water, sunshine, warm seas, scenery fantastic.

So our ideal day sail is:

• Depart the marina and set the mainsail, reef if it is appropriate
• Go upwind (with the correct headsail for the conditions) for 2-3 hours, half a dozen tacks, taking turns steering. We'll hit our upwind targets (6-7kts) in any wind within the 12-25 range.
• Bear away and set a spinnaker (which ever one is right for the condition that day)
• Drop the jib on deck and bungie to lifelines
• Gybe for our home port and hit high 9's and low 10's with a decent swell
• Arrive at the marina entrance, and drop the kite
• Sail into the marina on mainsail, and start engine at our fairway, dropping the main on deck
• Fold sails and put the boat away with the afterglow still present

We never really bother with a beam reach (They are boring)

We take people with us if we have to.

Wings: 43' 40 year old IOR race boat. Disp 18,000, Displ/Len 161 (Design Weight) Displ/Len 182 (Actual Weight) SA/Displ 20.89 (100%FT, design weight), SA/Displ 24.20400274 (RSAT, actual weight), Comfort Ratio 21.72 http://wingssail-images.blogspot.com/2008/01/wings.html


We have no furler, no lazy jacks, no slugs or slides, no snuffer or sock, tiller steered. Live aboard for 33 years, cruising for 23 years, circumnavigation & 450+ races, including a few podiums. Logbook available: Log Book Pages

Light boats, OK, Heavy boats, OK, moderate boats ROCK!

Fred & Judy

[Joli]

You guys have done it all and your words should be listened to and respected.
Keep on sailing and having fun!

Originally Posted by wingssail

10-15 is fine. 12-25 is better. We are both over 70, and our boat is not particularly easily driven (old IOR, I think you know the type), but here in our part of Mexico the sailing is stunning. Good winds, flat water, sunshine, warm seas, scenery fantastic.

So our ideal day sail is:

• Depart the marina and set the mainsail, reef if it is appropriate
• Go upwind (with the correct headsail for the conditions) for 2-3 hours, half a dozen tacks, taking turns steering. We'll hit our upwind targets (6-7kts) in any wind within the 12-25 range.
• Bear away and set a spinnaker (which ever one is right for the condition that day)
• Drop the jib on deck and bungie to lifelines
• Gybe for our home port and hit high 9's and low 10's with a decent swell
• Arrive at the marina entrance, and drop the kite
• Sail into the marina on mainsail, and start engine at our fairway, dropping the main on deck
• Fold sails and put the boat away with the afterglow still present

We never really bother with a beam reach (They are boring)

We take people with us if we have to.

Wings: 43' 40 year old IOR race boat. Disp 18,000, Displ/Len 161 (Design Weight) Displ/Len 182 (Actual Weight) SA/Displ 20.89 (100%FT, design weight), SA/Displ 24.20400274 (RSAT, actual weight), Comfort Ratio 21.72 <Wingssail Images-Cruising Photos from Around the Pacific>


We have no furler, no lazy jacks, no slugs or slides, no snuffer or sock, tiller steered. Live aboard for 33 years, cruising for 23 years, circumnavigation & 450+ races, including a few podiums. Logbook available: Log Book Pages

Light boats, OK, Heavy boats, OK, moderate boats ROCK!

Fred & Judy

[Dockhead]

Originally Posted by wingssail

10-15 is fine. 12-25 is better. We are both over 70, and our boat is not particularly easily driven (old IOR, I think you know the type), but here in our part of Mexico the sailing is stunning. Good winds, flat water, sunshine, warm seas, scenery fantastic.

So our ideal day sail is:

• Depart the marina and set the mainsail, reef if it is appropriate
• Go upwind (with the correct headsail for the conditions) for 2-3 hours, half a dozen tacks, taking turns steering. We'll hit our upwind targets (6-7kts) in any wind within the 12-25 range.
• Bear away and set a spinnaker (which ever one is right for the condition that day)
• Drop the jib on deck and bungie to lifelines
• Gybe for our home port and hit high 9's and low 10's with a decent swell
• Arrive at the marina entrance, and drop the kite
• Sail into the marina on mainsail, and start engine at our fairway, dropping the main on deck
• Fold sails and put the boat away with the afterglow still present

We never really bother with a beam reach (They are boring)

We take people with us if we have to.

Wings: 43' 40 year old IOR race boat. Disp 18,000, Displ/Len 161 (Design Weight) Displ/Len 182 (Actual Weight) SA/Displ 20.89 (100%FT, design weight), SA/Displ 24.20400274 (RSAT, actual weight), Comfort Ratio 21.72 <Wingssail Images-Cruising Photos from Around the Pacific>


We have no furler, no lazy jacks, no slugs or slides, no snuffer or sock, tiller steered. Live aboard for 33 years, cruising for 23 years, circumnavigation & 450+ races, including a few podiums. Logbook available: Log Book Pages

Light boats, OK, Heavy boats, OK, moderate boats ROCK!

Fred & Judy

Sailing in its purest form!

[picklesandjesse]

[QUOTE=wingssail;2966208]



Light boats, OK, Heavy boats, OK, moderate boats ROCK!

Fred & Judy

Have to agree. Like most things in life.