a constant source of disagreement on our boat is boom position on a beam reach. now my theory tells me to put the boom about 25 degrees from the Centreline. however this depowers the boat everytime. a notable increase in speed can be felt every time the boom is bought back into the centreline. so what's the go? I believe that bringing the boom back is doing more then just adding more heal..
Yesterday you posted a topic about your wife getting seasick, so my answer to today's question would be, the best position for the boom would be where it gives the nicest ride if your wife is on board.
After that it is probably a trade off between speed/heel and comfort.. There probably is a theory optimum, but optimum to what I wouldn't know..
Select to expand quoteToph said..
Yesterday you posted a topic about your wife getting seasick, so my answer to today's question would be, the best position for the boom would be where it gives the nicest ride if your wife is on board.
After that it is probably a trade off between speed/heel and comfort.. There probably is a theory optimum, but optimum, but what I wouldn't know..
haha.. 
true Select to expand quoteHG02 said..
Would you like a lend of a spinnaker
Bubble ?
I have the spinnaker but if your offering stuff your welcome and climb the mast and add a new spiniker down haul line after I droped the last insidethe mast when trying to replace it..
I always operate on the theory that the best trim angle for any sail is just before the luff starts to backwind. In other words let the boom out until you notice the sail start to lose its shape next to the mast then pull it in just a little from there until it stoops luffing. But beware if your genoa is over sheeted it will backwind you mainsail, so set your genoa the same way, you will find that the tell tails will fly parallel just before the luff of the genoa saris to lose shape (backwind).
and my other question is. how much pressure is to much pressure for the jib sheets? I was trimming them on so tight yesterday I was worried about pulling the car off the track.
I already snapped one block at the joint that the sheet feeds through on the jib track last year. although I think that it was more due to corrosion than pressure.
Good question Bubble. In my ' learn to sail in one easy lesson' book it indicates that the boom is
definately a few degrees off the centre line, but as Toph says.....whatever the best ride for the
Missus is the way to go. Seriously though, my inexperienced understanding is that the boom
IS some degrees off centre on a beam reach.
that a good video on theory of points of sail that I ha4 watched a few times
in practice it is as follows
close reach - boom in centreline
beam reach - boom on centreline
it usually goes like this.
sailing friend: pull the main sheet in a bit.
me: no its at its correct position for its point of sail, I read it on the internet
sailing friend: I bet we increase speed
me: OK.
(speed increase slightly)
me: bring the boom back to the theoretical position for the point of sail, I bet it was just a gust of wind that made it increase and it will be better in the "correct position"
( we slow down)
rinse and repeat exercise a few time with same result. resolve the fact that we are doing something else wrong with our trimming and the boom stays on the centreline.
boom comes off the centre line if we want to depower a little reduce heel when the wind gets above out 13 knts. 14 knts.
It might be that even when you let the boom out its not far enough and the sail is still over sheeted; or it could be that there is so much twist in the sail that boom position is not a good indicator of the sail angle
Try this next time Bubble
1. Don't worry about where the boom is
2. Just watch the luff and the tell tails on the leech of the main
3. Make sure your genoa is not over sheeted
4. use the vang and the traveller to get the tell tails flying free
5. trim the main to the point just before it luffs.
if that is not the fastest angle for the main then I need to go back to sailing school. 
I still don't understand all this terminology.. I just move stuff till the sails look right and the wind is pushing us along..lol..
Select to expand quoteandy59 said..
It might be that even when you let the boom out its not far enough and the sail is still over sheeted; or it could be that there is so much twist in the sail that boom position is not a good indicator of the sail angle
Try this next time Bubble
1. Don't worry about where the boom is
2. Just watch the luff and the tell tails on the leech of the main
3. Make sure your genoa is not over sheeted
4. use the vang and the traveller to get the tell tails flying free
5. trim the main to the point just before it luffs.
+1.
IMO when to adjust the vang and traveller in unison is a bit of a mystery to a lot of yachties. I have looked at a few boats over the last couple of months albiet under 27 feet and I'll swear the vang looked unused for years on a couple .
Select to expand quoteandy59 said..
It might be that even when you let the boom out its not far enough and the sail is still over sheeted; or it could be that there is so much twist in the sail that boom position is not a good indicator of the sail angle
Try this next time Bubble
1. Don't worry about where the boom is
2. Just watch the luff and the tell tails on the leech of the main
3. Make sure your genoa is not over sheeted
4. use the vang and the traveller to get the tell tails flying free
5. trim the main to the point just before it luffs.
if that is not the fastest angle for the main then I need to go back to sailing school.
I sail by the telltales, when I get them to fly free the boat gains speed and helm pressure reduces, ie the boat is balanced.
Im with you Mc Naughtical , when the boat is powering forward, the sails are full and not flapping, and it all feels right, then i reckon its right. Ben
Install a wool tell tail right in the middle of the main sail about 1.5 metres above the boom. Use that to adjust the boom, steer the course and get both sides to stream. Use the leech telltales to set the tension on the boom vang.
This is a video I made awhile back to show how lazy jacks look. It shows where to install wind tuffs on the main. I happen to be close hauled in the video but when reaching the main is eased so those tuffs still stream. Have to bear in mind the tuffs will only stream correctly with the correct luff tension.
and the luff tension is controlled by the halyard I presume, or a Cunningham.
I notice the leech of the headsail is flapping. is this an example of where a leech line would be tightend. the line that runs up the leech of the sail.
Select to expand quoteRamona said..
Install a wool tell tail right in the middle of the main sail about 1.5 metres above the boom. Use that to adjust the boom, steer the course and get both sides to stream. Use the leech telltales to set the tension on the boom vang.
I only pay attention to the boom vang when going downwind. I just leave it pretty slack for any upwind sailing.
Select to expand quotebubble7777 said..
and the luff tension is controlled by the halyard I presume, or a Cunningham.
I notice the leech of the headsail is flapping. is this an example of where a leech line would be tightend. the line that runs up the leech of the sail.
Yes I adjusted the leech line after I made the video as I mention in the notes.
Select to expand quoteMcNaughtical said..
I still don't understand all this terminology.. I just move stuff till the sails look right and the wind is pushing us along..lol..
pass another beer please Mc nautical
www.sailingbreezes.com/sailing_breezes_current/articles/Aug00/dell0800.htm
Found above an easy read
Select to expand quoteBen405 said..
Im with you Mc Naughtical , when the boat is powering forward, the sails are full and not flapping, and it all feels right, then i reckon its right. Ben
Thanks Ben
Next time you are out take some video of your main. I suspect your vang is not on hard enough. Alternatively maybe the main is flogged out.
Select to expand quoteHG02 said..McNaughtical said..
I still don't understand all this terminology.. I just move stuff till the sails look right and the wind is pushing us along..lol..
pass another beer please Mc nautical
Will do HG
The beam reach position should be the one that achieves the most speed with the least amount of heel.
There is a tendency for people to sheet in on a beam reach. Ease the sheets to the point where the sail leeches do not flutter and enjoy the ride.
Select to expand quotecisco said..
The beam reach position should be the one that achieves the most speed with the least amount of heel.
There is a tendency for people to sheet in on a beam reach. Ease the sheets to the point where the sail leeches do not flutter and enjoy the ride.
yup exactly what I'm doing. sheeting in hard. but what I guess I'm wondering is why is it giving me more speed to sheet it in hard ( pull the boom towards the centre)on a beam reach. Or to put it another way why is the "text book" sailing theory telling me to set a sail on a slower point. ( although I guess previous posts answer some of this question)
this is what I think might be happening
1. boom in correct position, all other sail trims terrible ( eg halyard, boom vang, traveller non trimmed headsail) = slow speed
2. boom sheeted in on centreline, all other sail trims terrible ( eg halyard, boom vang traveller, non trimmed headsail) = moderate speed
3. boom in correct position, all other sail trims awsome ( eg halyard, boom vang, traveller, trimmed headsail) = great speed
I'm achieving both 1 and 2 but never getting 3.
of course if boom is sheeted in, all other sail trim optimal for the main in its position, and I start hitting new world record speeds then i'll be really lost to understand what is going on.
Select to expand quoteYara said..
Next time you are out take some video of your main. I suspect your vang is not on hard enough. Alternatively maybe the main is flogged out.
will do
The vang is to adjust the shape of your sail. Ease it to make it fuller in lighter airs and get more power. Haul it in to get a flatter sail in stronger airs.
The main sheet and traveller are primarily to adjust the angle of attack of the sail to the wind.
So in a moderate breeze, say 15 to 20 knots, on a beam reach, you should have your vang as hard as you can get it, your traveller right down to leeward and trim for leech flutter with your main sheet. If the leech flutters, sheet in till it stops.
If the boat is heeling too much and it is uncomfortable, you may need to reef. With your ketch rig, get your main and mizzen right then trim your head sail. If you are getting overpowered, drop the main and hoot on the header and mizzen.
All Herrechoffs love that.
Hope this helps.
Select to expand quotecisco said..
The vang is to adjust the shape of your sail. Ease it to make it fuller in lighter airs and get more power. Haul it in to get a flatter sail in stronger airs.
The main sheet and traveller are primarily to adjust the angle of attack of the sail to the wind.
So in a moderate breeze, say 15 to 20 knots, on a beam reach, you should have your vang as hard as you can get it, your traveller right down to leeward and trim for leech flutter with your main sheet. If the leech flutters, sheet in till it stops.
If the boat is heeling too much and it is uncomfortable, you may need to reef. With your ketch rig, get your main and mizzen right then trim your head sail. If you are getting overpowered, drop the main and hoot on the header and mizzen.
All Herrechoffs love that.
Hope this helps.
Good info. but I don't have a ketch 
. the mizzen was removed many years ago 
What size headsail are you using, eg. 100% of foretrianlge, 130%, 150%?
I would suggest your increase in speed is because it is improving the flow between the main and headsail when beam reaching.
try dropping the headsail (or furling) and see if you get the same results?
It's the same as in fast assy kite boats. you have the main nearly on the centreline even though the leech telltales assy it should be half way out because on the centreline improves the flow between the assy and main.
If you have them rigged try clipping your kite sheets onto the headsail (using the barberhauler/tweaker to pull the angle down) and easing your headsail sheet so the kite sheet is controlling the headsail. This open up the back of the headsail and allows clean flow between the main and headsail.
Hi Bubble,
I struggled to reach on my Jog style 26' . I did what you described, ended up with boom on centerline feeling fast, but my telltale son the main were always back winding and I was also creating a lot of leeway, I'd end up down to leeward of everyone else.
The thing I was ignoring was moving my headsail cars forward, if you don't on a reach the clew height rises and the headsail loses a lot of power ( the top of the headsail was spilling a huge amount of air). Once I started doing this , I got a more uniform slot and better air across the back of the main ie: more uniform, and my telltales started streaming nicely!
It's embarrassing I spent so long screwing up till I learnt this! Hope this helps!
