Unequal upwind performance

[Pentium7]

Howdy all,
I have a problem that has me stumped at the moment so I am looking for some 3rd person sugestions.

My problem is that I am unable to achieve equal boat speed up wind in my Ross 780 trailer sailer. On starboard tack I can easily acheive 6.4 knots pointing high. The boat accelerates well after being slowed by chop. However on port tack I will only achieve 5.8 knots and that is at a lower ponting angle. The boat is easily slowed by chops and powers up poorly. It "feels" like it is stalling or on the verge of stalling. The boat heels over easier on port making me let out the main traveller.

It does not seem to matter what sail/reef combination I have up, the result is the same, starboard better than port. I have noticed that in heavy wind the difference in speed is more pronounced, up to 1.1 knots. In heavy winds it is very difficult to maintain a good boat speed and pointing angle. 6 - 6.2knots starboard an a max of 5knots port. It is also difficult to keep the hull below 20 degrees of heel angle on port.

I have visually checked to see if the mast is 90 degrees to the hull ie not leaning to one side due to unequal stay length.
I have visually checked to see if the mast is straight, ie no s bend.
The keel is of the drop version. I have checked for damage to the box holding the keel which would maybe allow for incorrect positioning ie slightly turned or leaning to one side but can't see anything obvious ( not ruling this out).

I have not been able to check the keel yet when fully extended in the water to see its positioning and alignment.

This is not a problem that has developed over time. The boat is three years old and I am its second owner. I have owned it for 6 months. I have noticed the difference since starting to race the boat 1 month ago ,prior usage was only cruising. Previous owner says he did not experience the problem (may not be true?).

Has anyone had a similar problem that may shed some light on this and possibly give me something to measure or check that we have not thought of or have overlooked in our overanalysis (its always the simple things)?

Thanks. (sorry for the length)

[jorgenl]

I had a similar problem and had a rigger perform a dynamic tune on the rig, i.e the rig is tuned while under sail.

I do not know exactly what magic stuff he did but it certainly seemed to fix the problem.

[LeftyI36]

I agree it's probably rid tension. But what about weight? When the boat was designed, does it appear they distributed the interior components equally, (ie, settee and head on the port side, but nothing on the other). Do you have water or fuel tanks or a bunch of heavy gear on the port side? An extra hundred pounds or so might make a difference.

[Sailormon6]

On a trailered boat, the most common reason I've seen for such a pronounced difference in performance on opposite tacks is because the prop of the outboard motor drags in the water slightly on one tack, but not the other. It might only drag in stronger winds, so, check it in different windstrengths. If it's dragging, study the motor's tilting mechanism. Often the motor can be tilted more than the owner realizes.

[Zogumwesterly]

I used to crew on a lightning and the upper rudder pintle on the hull had shifted(the bolt holes had enlarged and the rudder was cocked at about 5-10degrees. it took us a season to figure out, about an hour to fix and made a world of difference.

[Pentium7]

Thanks for the quick replies. I appreciate all your feed back.
I'm going to check all your suggestions out. I had not even thought of the rudder suggestion, cheers.
I'll keep you up to date on what I check and the results.
When I find the fault I will post the remedy.

Thanks again. I will check back later for any other suggestions.

[6string]

A couple of things you can do to check your mast rig on your own. With the boat level, on the trailer or in the water, hoist a tape measure with your halyard and lock halyard into place as you would for your main sail. Measure both port and starboard to the deck at your chain plate, being careful that it is exactly the same spot on both sides. The measurement should be the same. Also, while under sail to weather on each tack, with same mainsheet tension, (mark your mainsheet at a block and trim the same on each tack) sight your mast and note any bend it may have. Is it the same? On the boat I sail we want some bend but it is the same on each tack. Check stay tension to be sure it is the same on each side.

Is this a keel boat or centerboard? That could also be suspect.

I would also be sure that sail shape looks the same on each tack. Is the boom bending different on the opposing tacks? Are the jib leads coming to the same points on deck, is the travelor set the same on each side? These are the main things that I would look at as well as any slop that may be in the rudder.

Jeff

[Pentium7]

Howdy all,

Just thought I'd update. I haven't been able to do anything yet. We have had a low pressure sitting off the coast for the past week generating 40 - 65 knot winds with rain flooding etc. Quite a bit of a change to the drought conditions and water shortages we are experiencing latlely.

Hoping to do something next week end.

Cheers

[metalcrafter]

Hi

Had the same problem on my Elite-37. Couldn't for the life
of me figure it out. Asked Around got all kinds of answers/suggestions. Then one light air day I noticed the roller furled jenny had taken a set , kind of like a rolled up piece of paper.My sail, furls up clockwise, resulting in which it lifted great to starboard & lousy to port. If it were to furl counter-clockwise I would expect it to lift vice-versa.
Hope this helps

Metalcrafter

[Pentium7]

Thanks for the input Metalcrafter, unfortunately my rig doesn't have a self furler (wish it did).

I was able to have a close look at the mast this weekend without sails on. I noticed it had a very slight sideways bend to port. My type of rig uses an adjustable forestay tension system. With light tension the bend is very slight and hardly noticable, but when tension is applied the bend is quite severe. This would explain why the difference in performance is more noticable in heavy conditions when more forestay tension is applied.

As a result of this discovery I will be retuning the rig. I'm just trying to get the suggested mast rake from the boat builder and the suggested mast prebend from the sailmaker. This rig is fractional with heavily raked spreaders and is a bit unique in that you can adjust the forestay tension through a pulley system, should be quite an interesting challenge.