L400 performance

[2Hulls]

OK Monte - you confused me. Does "around the west of tortola up to little harbour" mean "north up to Little Harbour JVD"? Your chart suggests you came south and around Thatch Island, then beat upwind into Drake Channel.

Regardless, more pictures of Jen and less of instruments.....

Dave

[monte]

haha yes sorry for the confusion, yes we sailed from JVD south around Thatch island then east to little harbour on peter island.

[arsenelupiga]

Originally Posted by monte

Just an update on this thread and our observations. Maybe I was premature in the previous windward performance observations (or just couldn't sail the. L400 as well) , but after more sailing I have to say we are really happy with the L400 at all points of sail.
We just sailed around the west of tortola up to little harbour and beat into a nice 16-18K easterly with a fairly mild sea state, a bit rough in the channel between tortola and St. John but otherwise a nice sail.
Average SOG was around 7K with tacking angles close to 90 degrees, into a 1K+ current.
TWS here should be closer to 18K but fluctuates with swell etc.
Attachment 98597
Attachment 98598
Log showing 8K through water and opencpn showing 6K SOG. Some current.....
Attachment 98599
Jen helmed the whole way and did a stellar job. I handled the sheets and fumbled a couple of tacks...
Attachment 98600

going 8kn thru water at 20.5 apparent at 35 deg apparent is way above lagoon 41 polars.

translated

"The direction to the true-wind is 53.21 degrees off the bow!!
The speed of the true-wind is 14.68 knots!!"

Based on Lagoon 41 polars, you should be doing 6.5 kn. Overshot for 1.5 kn which is amazing.

You sure instruments are realistic ?

[monte]

Yeah they're pretty well tuned. I regularly check the log against the gps and it usually make sense withe the expected currents, none, with us or against. The windspeed we re calibrated by dropping it 20% after comparing with 3 other boats and it seems good. Wind angle not so good but the gps track shows the state if things. I don't put any faith in the polars, it's best to sail and make your own to get a feel for what you can expect. Our boat is in full cruising trim so I'd expect better performance without all the gear. I finally found the VMG setting on he Raymarine instruments and have been playing around with that the last couple of sails. I find the VMG to windward pretty useless as it fluctuates too much, relying on the data from the wind gear. But placing a waypoint well to windward and setting it VMG to WP gives very good data, allowing us to maximise upwind performance. I find 17-25 AWS (12-20 TWS) a nice sweetspot for upwind sailing on the L400 with full sail.
I did put a (rather boring) vid on YouTube last week with a bit of performance data on it.
http://youtu.be/H3BMzVrTtFI

[arsenelupiga]

thks. watched the video. Nice.

Learning to sail better and are way behind you. My boat quite empty compared to yours, i bet. But still fully equipped.

learned that spi blocks can be neatly used to trim jib.

I get it to sail real well sometimes, after tweaking sail for a while and got so far close to 10 kn, where water hitting the bow came continuously over the top of stern which was real impressive. Wind was well below 20 kn and 1 reef.

I was afraid to ruin the sail setting but next time will have to, to learn how to get it back.

[2Hulls]

Hi Monte - thanks for the video link. Hope you enjoyed Dominica as much as we have.

I noticed your auto pilot was reacting quite a bit. My Raymarine is much older than yours (2001 ST7000+), so perhaps this doesn't apply to your unit, but I have a "Response Level" setting that allows me to adjust how sensitive the AP reacts. I keep it on Level 3 (of 3) that makes it the most casual, but saves a lot of power and wear and tear. Or maybe you have intentionally chosen a more active setting - obviously a personal choice.

Dave

[monte]

Thanks Dave. Yeah loved Dominica again. Yes the response setting is set on 5 as default and I usually leave it there unless I think I can reduce it. On that sail I probably could have reduced it to three or four. Thanks for the heads up, I'll experiment a bit more with settings...learning every day

[2Hulls]

Monte - I made a mistake: Level 1 on my AP is the most casual response level, not level 3. Sorry for the confusion. My oldstimers disease again....

Dave

[monte]

All clear Dave. Ours ranges from 1-10. I haven't tried it over 6 or below 3 but I will try setting lower for sure. The constant jerky motion on 5 isn't so nice, although it does maintain course well. We have been hand steering quite a bit lately. Jens been enjoying it and it's good practice for both of us instead of relying on the ap 24/7. Also the seaweed in the Caribbean this year is ridiculous. Huge islands of floating kelp just waiting to attach to the rudder. Hand steering alerts us to the problem a lot sooner. Some sails I've had to head up to wind every 30 mins to drop the weed from the rudders at zero knots. Hand steering allows us to steer around some of the bigger patches but picking some up every hour or so is still pretty unavoidable. It's surprising how much a small amount of weed around the rudder effects performance and weather helm..