Sailing too flat?

[bcardarella]

I've been focusing on trying to optimize boat heel while racing and recently have found some success sailing flatter than with heel. However, last night I probably over did it and sailed very flat in a moderate breeze and I was noticing that my telltales were breaking at TWA that were about 5 - 8 degrees lower than what my boat's polars (ORC) say I should be at. The angle of the jib luff is of course changed when the boat is flat vs heeled so I am wondering if the telltales will break earlier when flat or is there something else happening?

 

[Marty Gingras]

Interesting. I can't imagine a mechanism for that much difference in how the telltales fly. My thoughts jumped more to your instrumentation. Was your performance poor relative to your competition?

 

[bcardarella]

I have a sister boat in my fleet and we sailed horribly. Bad start didn't help but I was certainly sailing lower than they were. The only real difference I made this week was sailing more flat.

 

[longy]

What boat?? Heel angle won't change AOA. But it does make keel work better. Look at pics from high end racing for your boat & see what the leading boats do.

 

[Marty Gingras]

I have a sister boat in my fleet and we sailed horribly. Bad start didn't help but I was certainly sailing lower than they were. The only real difference I made this week was sailing more flat.

What (all) did you do to sail so flat (e.g., depower w/backstay; crew weight only)?

 

[bcardarella]

@Marty Gingras the wind got pretty light during the race. Started out on the edge of overpowered to us being probably out of gear with the rig.

 

[bcardarella]

What boat?? Heel angle won't change AOA. But it does make keel work better. Look at pics from high end racing for your boat & see what the leading boats do.

Seascape 24. I would think that the boat being on a heel does actually pull the leach away from the actual TWA but it may not be enough that it is effecting anything. For the jib leach the only other control I can think of that would change this is if the tension on the leach is flatteing the sail. Having more body on the windward side should give me a few degrees more to play with I would think

 

[MPongs]

Just a theory out there, but the SS24 has a pretty wide stern, could it be in lighter wind, sailing it too flat creates too much drag forcing you lower to keep speed up? Did you try I believe what is called the fourth mode where you move forward to press the bow down to give some bite for the boat to go upwind and release the stern?

Also I do find on square tops like your in light winds, if you sheet too hard on the main and drag the leech, it basically is a constant acceleration and deceleration of boat speed (and very slow way to sail) that forces you to sail lower to maintain the jib tell tales at a specific angle.

 

[Marty Gingras]

Seascape 24. I would think that the boat being on a heel does actually pull the leach away from the actual TWA but it may not be enough that it is effecting anything. For the jib leach the only other control I can think of that would change this is if the tension on the leach is flatteing the sail. Having more body on the windward side should give me a few degrees more to play with I would think

Cool boat. Looks like a boat that wants some heel in light wind, but that doesn't explain your observation re: telltales.

 

[bcardarella]

Just a theory out there, but the SS24 has a pretty wide stern, could it be in lighter wind, sailing it too flat creates too much drag forcing you lower to keep speed up? Did you try I believe what is called the fourth mode where you move forward to press the bow down to give some bite for the boat to go upwind and release the stern?

Also I do find on square tops like your in light winds, if you sheet too hard on the main and drag the leech, it basically is a constant acceleration and deceleration of boat speed (and very slow way to sail) that forces you to sail lower to maintain the jib tell tales at a specific angle.

That's an interesting thought, I didn't consider. I can start to play with that.

 

[El Borracho]

Match exactly what your sister ship is doing. When you are able to pace them you can start testing changes.

 

[longy]

OK, your keel is somewhat skinny, so it is crucial to establish flow across the foil before trying to point to high. Get to slow & the flow will detach, and the keel will want to go sideways. Also, with your wide stern, some heel is needed to reduce wetted surface. As E B says, watch how the faster boats are sailing

 

[ryley]

Hey @bcardarella, our boat likes flat too, but I think that in the light stuff we feel better when we induce a little heel and get some pressure on the rudder. I think your boat is similar, wants to be on the chines. But at the same time, I don't think you're generating much lift from that keel unless you've also got about 4 degrees of weather helm. Wednesday we were sailing heeled downwind too, just to keep some helm pressure. I'm sure you already do this but the Seascape's wide ass begs for you to move weight forward as well to get the transom out of the water especially in the light. On my boat it's worth about .2-.3 knots in light air to get some weight in front of the spreaders.

 

[Mid]

wetted surface area .

 

[Major Tom]

A lot of boats are designed so that optimum waterline length and width is achieved at a certain heel angle, too flat and length decreases and width increases as does wetted surface area. As mentioned above helm also goes too neutral and looses feel and bite. In lighter conditions the trick is to get to the correct heel angle immediately after every manoeuvre, this takes a lot of practise and crew communication .