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Go Back   SailNet Community > On Board > Gear & Maintenance > Sailboat performance change
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Thread: Sailboat performance change Reply to Thread
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Topic Review (Newest First)
12-10-2013 12:30 PM
Waltthesalt
Re: Sailboat performance change

Dodgers should be fold-downable. Maybe larger plastic windows would help. Walk the docks to see one that you like and then ask the maker for ideas . Smaller main affects balance, probably not a big item on the Cal as they use a variety of jibs.
12-10-2013 02:20 AM
Barquito
Re: Sailboat performance change

My first thought with regards to performance would be that because the center of effort of the sail is raised, then, given that there is less sail area, at the wind speed that would produce the same amount of power as the bigger/lower sail, the heeling force would be greater... but probably not enough to worry about.

With regards to the dodger design: I would lower it, and look over the top.
12-09-2013 02:10 PM
Delta-T
Re: Sailboat performance change

Quote:
Originally Posted by Alex W View Post
This is not universally true. It is true of many 70s boats that were designed to IOR handicapping rules.

Saying that the main gives you heeling and weather helm adjustment is also not accurate. The main still gives you power, it is just that most of these boats had 2/3rds of their sail area on the head sail. You can prove this by dropping your main sail and seeing that you slow down (unless you are in heavy air) and won't be able to point as high.
I sail 80% of the time with only the 150% head sail. Boat is well balanced this way. And yes, head sail gives me better pointing. Sailing with main only is not an option for my boat, boat goes nowhere without head sail. I always wondered why, assuming the placement of the mast is too far back. But now we are going OT. And, as you point out performance is different for each size and design of boat.
12-09-2013 12:57 PM
Alex W
Re: Sailboat performance change

Quote:
Originally Posted by Delta-T View Post
If understand it correctly, the head sail gives you power and the main gives you heal (and weather helm adjustment).
This is not universally true. It is true of many 70s boats that were designed to IOR handicapping rules.

Saying that the main gives you heeling and weather helm adjustment is also not accurate. The main still gives you power, it is just that most of these boats had 2/3rds of their sail area on the head sail. You can prove this by dropping your main sail and seeing that you slow down (unless you are in heavy air) and won't be able to point as high.
12-09-2013 12:15 PM
Delta-T
Re: Sailboat performance change

Quote:
Originally Posted by chucklesR View Post

On the other hand....
I was just going to do that....lol

On the other hand, The bigger the dodger the more resistance. And I hate looking through the dodger anytime. I would prefer to have no dodger, but hope to have waves braking over the bow every time I go out. Go ahead and call me a cruising *****, I good with that. I don't own a racing boat. But I will give you a run for your money with against cruiser. My vote is for smaller dodger, but the question was if performance would be compromised. And at what wind speed, after 17k apparent (give or take), you will have more sail than you need.

Edit...hahaha I was censored "*****"
12-09-2013 12:04 PM
chucklesR
Re: Sailboat performance change

Simple math tells the OP's original line - you will loose about 7 sq ft of main sail.
You will loose it at the bottom where the wind is slowest, you will loose it along the boom where the wind is squirrely anyway.

On the other hand, it will be expensive, more so than lowering the dodger and making a window in the connector between the dodger and the bimini.
I don't have a good pic of ours - here you can see the tan colored phifertex covering the isenglass, and the dark blue in the center is a removable cover as well. The phifertex is 80%, you can see through it for most purposes, but not enough to be safe underway, it comes off for full visibility, and a full blue cover goes on for sitting at the dock most times.

Full enclosures get hot.

12-09-2013 11:46 AM
Delta-T
Re: Sailboat performance change

If understand it correctly, the head sail gives you power and the main gives you heal (and weather helm adjustment). So IMO you would see little dropped performance issue. Did I miss you saying if you are racing or cruising? Sound like you are a cruiser, having a dodger and if performance was a real issue with you would take it down. And, I am surprised no one has mentioned the air stream of the rack of the windshield, more vertical will act more like a sail! That can be bad and good...I can do 2k down wind with no sails up. On my old boat I have a track, 12" long, to adjust the height of the boom. There was a thread a short time ago about the usefulness of this track and as others have done and I did a long time ago was to tack the car from moving. Mine in the all the way up position, my boom just clears my dodger. I am not racing, but would think the lower the center of gravity the better, but not sure if that apply s to the main.

Edit: If you raise your main 6" and shorten the sail you will only be changing the center of gravity 3"
12-09-2013 11:14 AM
Alex W
Re: Sailboat performance change

Bimini-Dodger combos can make it really hard to see out of the cockpit and to see sail shape. I like the shade that the bimini provides for a couple of weeks a year, but hate it most of the time. However you are in FL and they might be a fact of life there.

Are either of them designed for quick folding? In FL I'd think that you'd want to be able to fold the dodger down quickly so that you could get a breeze through the cockpit anyway. On some dodger designs this is as simple as unhooking two straps (one on each side) and pushing it forward against the cabin top, it really only takes a few seconds.

If that is the case you could just fold the dodger down before docking.

Otherwise I agree with others that the best plan is to lower the dodger, not raise it.
12-08-2013 10:39 PM
Sabreman
Re: Sailboat performance change

Instead of raising the dodger, consider lowering it so that you can see over it. That's the situation that we were in when we bought Victoria. Looking through a dodger is not nearly like looking through a windshield of a car, even with pristine Stratglas. So we lowered the dodger to a height that my wife could see over. The dodger is really only meant to be sat under, after all. It looks better and the angle of the forward screen is more raked, better matching the cabin top lines. Faster is right.
12-08-2013 08:47 PM
windketch48
Re: Sailboat performance change

Hi Again...

Yes I have a Bimini top. The forward frame is even with the vertical midline of the boom profile ands about 6in aft of the boom's end when it's centered. The view that the "low" dodger limits is not that of the sails, but the view fwd of the vessel in general. Not safe when negotiating unfamiliar water, especially channels. The thrust of my question was to raise the height of the roof of the dodger (thus making the fwd statglas window more vertical), raising the foot of the sail (and therefore the boom as well) by the same amount, estimated to be 6in. By lowering the Bimini slightly I'd be able to get a cover flap from the fwd Bimini rail to the aft dodger rail and thus close that rain gap as well. My concern has been any serious potential change in seaworthiness due to the relocation of the CE of the mainsail.

Thanks
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