Just bought a displacement centre board yacht which can be sailed without putting the board down.
It also has a transom hung rudder, I learned quite quickly That it ease the weather helm by putting the board down even a little, and of course having the main set up the right size also helps hugely.
the rudder goes down quite away and i am wondering if it's to deep as it takes a madive effort to turn it, I know I am getting old and nothing is as easy as it once was but this is really annoying.
i have reduced the main to third reef which has helped but when the boat gets going the pressure is strong.
the rudder turns ok normally when stopped I have played with the centre board and have run out of ideas.
Any great minds have any suggestions?P.S. it's not so much weather helm it's just very hard to move , if I get a big gust then I really have to put all my strength in to overcome the weather helm,
Just a few questions to clarify:
- What sort of boat is it?
- Are you doing anything with the headsail when you are reefing the main?
- Have you tuned the rig - mast rake affects weather helm
- What is the underwater profile of the rudder like and where does it pivot in relation to it's center of effort
It is a Aquarius 23 draws 2ft without the board 4ft with it down has 1400lb ballast so is quite stiff, have left the head sail alone thinking it may create lee helm, I have had a look at the mast but as with all new boats my attention is spread everywhere at once, I have noticed there are three sets of holes in the mast step for pin it is in the back one so I do have two holes to move mast forward I really am pinning my hopes in that making a difference probably would move the mast 3inches forward . I have started on the turnbuckles spraying them and working them they haven't been used for years. The mast didn't seem overly raked back but it must be doing something..
the rudder folds up but when it is down it is deeper than the fixed keel so over 2ft
Select to expand quotelydia said..
Tilt the rudder blade further under the boat.
I reckon Lydia could have picked it. The lower half lifts up for shoaling/trailer, true? If it's not staying in place and lifting as you go faster, this would definitely fit with your description of Mr. muscle time.
Can you get a good look at the rudder next time when she is all powered up?
Yes a deep rudder as per the link here and as per Lydia if it is not fully lowered down its centre of effort will be well behind the rudder pintles creating the issue of being very hard to move. See the photos in the below link where the leading edge of the rudder underwater is intentionally parallel to but ahead of the rudder pintles to give a bit of balance and avoid excessive load - most transom hung rudders have this and rudder stock hung rudders have the same by means of locating the stock in the rudder appropriately, with un-notched leading edge obviously - albeit I had a Black Soo a long while back where this was overdone and had to cut back the leading edge about 150mm.
www.phillippdunn.com/Aquarius%2023/Aquarius%2023.htm
Would not "leave the headsail alone to create lee helm" rather hoist your no2 jib and full main and get the boat balanced with them in 12-15kts wind. Trust you are not jamming on your mainsheet excessively or setting it too full as this will make the boat gripe to windward.
Mast rake should be about 1-2 degrees.
CorrosionX will free the turnbuckles faster than anything - it is spendy though, but worth it.
Thanks for the replies it may be a chance it is coming back up a little as I have tightened the bolt and it still won't stay up when I lift it so it may well be doing the opposite while under way , it is interesting having more options to play with like being able to lower or raise the centre board to adjust effort and drag , more work to do cheers
Select to expand quoter13 said..
Yes a deep rudder as per the link here and as per Lydia if it is not fully lowered down its centre of effort will be well behind the rudder pintles creating the issue of being very hard to move. See the photos in the below link where the leading edge of the rudder underwater is intentionally parallel to but ahead of the rudder pintles to give a bit of balance and avoid excessive load - most transom hung rudders have this and rudder stock hung rudders have the same by means of locating the stock in the rudder appropriately, with un-notched leading edge obviously - albeit I had a Black Soo a long while back where this was overdone and had to cut back the leading edge about 150mm.
www.phillippdunn.com/Aquarius%2023/Aquarius%2023.htm
Would not "leave the headsail alone to create lee helm" rather hoist your no2 jib and full main and get the boat balanced with them in 12-15kts wind. Trust you are not jamming on your mainsheet excessively or setting it too full as this will make the boat gripe to windward.
Mast rake should be about 1-2 degrees.
CorrosionX will free the turnbuckles faster than anything - it is spendy though, but worth it.
R13 I lashed the rudder down , I was surprised how much further it went down , so that was the first hint we where onto something, then went for a sail WHAT A HUGE DIFFERENCE thank you so much .
Select to expand quotelydia said..
Tilt the rudder blade further under the boat.
Lydia you are a genius how did you know that ? Thank you mate
Select to expand quoteshaggybaxter said..lydia said..
Tilt the rudder blade further under the boat.
I reckon Lydia could have picked it. The lower half lifts up for shoaling/trailer, true? If it's not staying in place and lifting as you go faster, this would definitely fit with your description of Mr. muscle time.
Can you get a good look at the rudder next time when she is all powered up?
Shaggy You where spot on word for word That was exactly what it was doing thank you mate
Select to expand quoteZzzzzz said..lydia said..
Tilt the rudder blade further under the boat.
Lydia you are a genius how did you know that ? Thank you mate
Years of dinghy sailing.
Here is an example.
Years ago when quality control on Lasers was not great you would go to the factory to pick a boat.
Generally you looked for two things.
One was mast rake measurement and secondly and as important you checked the amount of filler in the deck to hull join on the transom.
Less filler meant that the transom face was more upright and so rudder pintle were more upright and so the rudder was further under the boat, meaning less helm meaning faster.
Simple
Sailing 470s was another were rudder angle to transom was crucial.
Lydia sounds like you are the right person to ask about the use of the centre board, I have noticed the yacht is so much easily driven with the board up is there a base rule of lifting ? I assume you lift when going down wind but is it true the faster you go the smaller it can become ?
There is a lot in the full answer to this. See excellent summary here;
www.trailersailerplace.com.au/phpBB3/viewtopic.php?t=2357
And a bit more here.
www.mysailing.com.au/news/a-balanced-boat-is-safer-to-sail
Assume an A23 owner on trailersailerplace would answer more specifically for you.
The A23 having a swing steel plate centreboard will have 2 main impacts when it is raised from it's fully down position;
1 The stiffness % of the boat provided by the centreboard will inherently reduce. This % provided by the cboard will not be high to start with as the cboard is not heavy and the design has a lot of internal ballast - in the stub keel presumably. Nevertheless as you raise it the righting moment of the boat will reduce slightly.
2 As the cboard is swung up it's centre of effort will move aft and this will inherently reduce weather helm and increase lee helm.
In very broad terms it is probable that the boat sails best to windward with the board swung fully down, and reaching and running with it raised a bit - say 1/4 way up reaching, 1/2 up running - for reaching the lateral hull stub keel and cboard area doesn't need to be as much as for going to windward to reduce leeway, and for running even less is needed. I would be careful raising more than 1/2 up when running except in very light winds and flat seas - the boat could become skittish and roll excessively in heavier winds / larger waves and have a tendency to not track well.
Of course there are safety issues also - having any ballast which is not locked might not pass the latest RRS, or your insurance. All centre boards which are the vertical lift / lower type in a typical centre board vertical or near vertical case have locking pins. Expect all swing cboards do as well.
Then maintenance comes in as well - cable or hydraulic lift systems for lift or swing cboards need to be properly maintained with suitable inspections at relevant periods, and maintained / repaired with new components as needed. Back-up fail safe securing systems must be included in the design. Plenty of cboards have fallen out of boats over the years unfortunately.
You are also changing the amount of lateral resistance and the centre of resistance
sometimes in waves you want to do that especially so the boat slides sideways rather then trip on the keel/board
Thanks Lydia I am banking on the boat sliding side ways in big waves as a storm tactic like a boogie board on a wave catch me if you can dodging the punch 
Remember also that, just like your rudder, the potential forces on the centre board pivot and the c/b case increase as you lift it up partially.
Select to expand quoteYara said..
Remember also that, just like your rudder, the potential forces on the centre board pivot and the c/b case increase as you lift it up partially.
I can't get my head around that one Yara I thought most pressure would be the leaver affect of the board right down ?
