Hallberg-Rassy 36 pointing ability

Discussion in 'Sailboats' started by Alby1714, Jan 31, 2017.

  1. Alby1714
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    Alby1714 Junior Member

    Hi,
    I have a Hallberg-Rassy 36, a well known cruising design of German Frers . The boat is excellent in all points of sailing except upwind. I am not racing but I do have concerns for the safety aspects of poor upwind sailing in a cruising boat and the obvious risk of not being able to claw off a lee shore in bad conditions.
    The pointing angle (without pinching) to the true wind in light airs and flattish seas is acceptable (90/100 degrees between tacks). This is obviously the case when sailing with the full main and full genoa.
    It is when the wind pipes up and the sea becomes rough that the windward performance deteriorates badly. In those rare instances when the destination lies dead into the wind it is a pain to have to beat with angles of around 120 /130 between tacks while keeping the angle to the apparent wind at around 40 degrees. The speed through the water is good but there is obviously a lot of leeway and progress to windward is slow and painful.
    In these conditions (wind speeds from 25 knots and beyond) I am normally sailing with two/three reefs in the main and a very reduced genoa, sometimes I roll completely the genoa and sail with a hanked on jib on the inner forestay, but in both configurations the pointing angle is poor.
    I suspect there is not much that can be done but nonetheless I would like to understand better the fundamental reasons for this which I believe are to be found in the underwater lines of boat.
    Please correct me if I am wrong, I am no expert and this is why I am turning to the very competent people of this forum.
    The boat has a moderate draft of 1.7 meters (approx.5,5 feet) and according to my rough estimate a ratio of full sail area to keel area of around 3%.
    My idea is that an increase of draft, say to 2 meters (6.5 feet) associated to a larger keel area (say up to a full sail area to keel area ratio of 3.5%) would probably improve significantly pointing ability (at the expense of a slightly larger wetted surface a point of no concern to me).
    I would be very interested to hear your thoughts and comments. Thank you.
     
  2. JosephT
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    JosephT Senior Member

  3. Alby1714
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    Alby1714 Junior Member

    Poor pointing ability

    Thank you Joseph T for the suggestion. As I said in my post I have a proper inner forestay on which I can hank a jib. That in my experience does not make any difference. What I have not yet tried and it is suggested in the article is to add a barber haul to make the slot between jib and main narrower. Indeed it sounds like a good idea and I will try it. Nevertheless I would invite comments about the boat design as my sails are not baggy and while beating the angle to the apparent wind is good as it oscillates around 40 degrees and the speed through the water is also good. Yet the problem becomes apparent when one checks the angle between tacks as that reveals a large leeway angle. I understand that as the wind increases, drag increases faster than boat speed and that determines an increase of leeway. The question is: an angle between tacks of around 120 degrees with a wind of around 25 knots is reasonable or the designer has sacrificed some lateral wet surface and upwind performance with it, to the benefit of other boat characteristics ?
    If the latter is true there is no obvious practical cure but I would nevertheless welcome any technical explanation able to pinpoint the origin(s) of the problem.
     
  4. CT249
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    CT249 Senior Member

    It's almost impossible to diagnose a problem on the internet because sailing ability varies so much. To take one example, in 25 knots the sailors at the front end of a good Laser fleet are having fun, while the sailors at the back end are looking for a rescue boat. Similar issues apply in cruising boats.

    Can I ask whether you have searched for a VPP for the boat? Does it have a rating under a well known system such as IRC, ORCi, or HN? An ORCi rating is a fairly sophisticated system that will give you a fairly good idea of the speed and angle your boat should make across a range of conditions.

    One simple thing you could do, which is much cheaper than modifying the boat, is to take a few pics of your boat under sail and then go and show them to a local sailmaker. They should be able to look at them and tell you whether your sail trim and helming are roughly correct or not. For example, they should be able to give you an estimate of the sheeting angle to which your jib should be barber-hauled, the depth of the jib when trimmed, and the helming technique. If you are going upwind in strong winds and flattish water the windwardheadsail telltales should generally be lifting 45 degrees or so. Some sailors try to keep them streaming horizontally which is not generally effective in strong winds. Other sailors don't have any telltales, which is a problem in itself.
     
  5. JosephT
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    JosephT Senior Member

    I agree. I'm not aware of any major upwind issues with this boat. It's very easy to spend days describing various theories. If you know someone with a GoPro or other video camera I would suggest you mount it to the stern of your boat on a pole. Then do this test:

    1. As you prepare to head upwind make a note of your intended bearing/destination.

    2. Tack to port/starboard as needed and make a note of your tack angles. They should generally be the same.

    When you reach your destination (or you're fed up with tacking!), stop the video and upload it to YouTube. This will allow us to examine your sail rig, heeling angles, etc.

    A last bit of information would be a profile picture of your boat so we can see how it is loaded. I know if you're too heavy on the stern this can negatively impact upwind performance. If anything your bow should be a bit heavy (1-2 inches below normal waterline). This helps prevent drift and can improve speed as well.
     
  6. Alby1714
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    Alby1714 Junior Member

    CT249 and Joseph T,
    thanks for your thoughts. I agree it is difficult to analyze an issue of this kind in the forum, still some of the points you have touched make me think. For one thing my boat is heavy. After 5 yrs of cruising away from home all sorts of equipments have found their way onboard, hardly anything has been disembarked. Perhaps even more important I know I am heavy on the stern. The idea of making a video while tacking repeatedly is good but I won't be able to do it until I go back to the boat which is currently on hard and away from home, (launch planned for June).
    For your reference I attach the designer's polar diagram for the boat which shows the boat capable of sailing in 20 knots of wind close hauled at less than 45 degrees to the true wind at a speed through the water in excess of 6 knots. This is plausible and matches well my experience even with the boat heavily loaded as it is at the moment. The sore point is that the diagram does not (cannot) say anything about leeway. A loaded hull deep in the water and heavy on the stern may generate additional drag. If that is the case however, this additional drag in my experience does not seem to slow down the boat through the water but rather it seems to act sideways increasing leeway. Can this be expected from the theory of sailing to windward ?:confused:
     

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  7. JosephT
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    JosephT Senior Member

    Without modifications to the boat, my only suggestion would be to consider moving heavier gear as low as possible to lower the CG and try to get the bow down a bit. Also, do try to get that extra weight out. I've never sailed in a boat that was too overloaded, but I know it causes problems and changes the math on the hull.

    Rule of thumb: If you look at something on the boat that's not essential to operation and have to think twice about it: Get it out of the boat.

    If you're considering a modification with a larger keel (which will help, but may not be necessary if you lighten the boat), I would suggest discussing first with the manufacturer. They should be very familiar with the performance of the hull and offer additional tips. Definitely do that before considering the big step of a larger keel. Below is the contact info for the main office.

    http://www.hallberg-rassy.com/contact/main-office-in-sweden/

    The last several years I have done quite a bit of offshore sailing in stormy weather. To stay on course upwind and achieve the best speed (in a properly loaded boat) I won't usually bring in a full 3 reefs unless it's a squall. Now you can expect the boat will heel over more with only 1 or 2 reefs in, but you can ease the main sheet until you find that sweet spot that delivers maximum power and keeps you at closer tacking angles. Of course helming in heavy seas like this requires a safety strap so it's a given that you are wearing one. If that boat is loaded & trimmed out right cavitation on either end of the hull will be reduced and it will help for sure.

    Before you come off the hard I would also weight the boat to see where it's at. Zap Hallberg Sassy an email and explain your situation. They'll probably tell you to lighten the boat too. It won't feel or perform the same as a properly loaded & balanced boat. With the manufacturer weighing in you can be a lot more confident in your final decision.

    Fair winds (and clean out that boat) ;)
     
  8. tane
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    tane Junior Member

    just theorising:
    immaculately clean underwater?
    heavy overload badly distributed ? (lots of chain forward, stern-arch, -anchor, dingi-in-davits,...), jerrycans on deck?
    even an inner forstay+sail will not get rid of the tremendous drag & high cg of a rolled up foresail
    for a 36'er the draft looks on the shallow side to me
    seems unlikely to me that GF would design a "dog"...
    every boat design is a compromise, changing one parameter (draft) will not make a racehorse out of loadcarrier...
    just musing...
     
  9. Alby1714
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    Alby1714 Junior Member

    Tane,
    yes I keep the underwater very clean at all times but most of your other points are correct: I have a stern-arch with (solar panels and wind generator), I have the liferaft just outside of the stern pushpit. I have a storm anchor in the stern lazarette and lots of chain forward and lots of additional chain in the cockpit locker ( I spent a couple of hurricane seasons cruising the Caribbean), and I normally cruise with both water and diesel tanks full, the list is endless....the weight and its distribution are most likely the problem.
    Thanks for your thoughts.
     
  10. philSweet
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    philSweet Senior Member

    My first guess is the problem lies in the roller furling headsail. If you have several headsails, drop the genny and hoist a smaller sail. You can also modify the furling headsail luff with some rope or foam padding to help it to better maintain shape. This is a common cruiser mod. You can also change things around to use a drifter for light air, and reduce the size of the genny for cruising. In high-wind cruising areas, a cruiser ought to carry full sail in 25 knots with no trouble. First reef in main would be for 22 to 30 knots apparent. If you are trying to cover miles with three feet of genny's foot rolled up, you are simply set up wrong. That isn't the boat's fault.
     
  11. tane
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    tane Junior Member

    "If you have several headsails, drop the genny " - ever dropped a genny of a 36'er out of a rollerfurler in 18kn true? sailing with hanked on foresails is childs play compared to it.
    the one key to satisfaction with the sailing abilities of the smallish long-term cruising boat: never ever sail it before you load it down with all it's gear & provisions!!!
     
  12. Alby1714
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    Alby1714 Junior Member

    philSweet,
    thanks for your suggestions, good food for thoughts. Actually, as pointed out in one of my early posts, simply I do not have any problems in light airs and I would add that even when it starts to blow the boat behaviour and handling is excellent. It is the pointing ability in presence of wind and waves that I find somewhat wanting. Some of the posts I have received suspect that this may be due to the excessive weight that I carry and its unbalanced distribution about the boat. I believe now that that may indeed be the case.
    Having said that, there may be other factors as well, and one of these, as you hint, might also be the way I sail.
    You say that "a cruiser ought to carry full sail in 25 knots with no trouble. First reef in main would be for 22 to 30 knots apparent." I would argue that it depends a lot on the state of the sea and on what you are doing !
    If, by way of example, the wind has been blowing for days on end at 20 kts then one would be beating against waves that will force to take that first reef much earlier than one would if one was beating in the same wind speed in the lee of land and on a flat sea.
    Along the same lines, considerations for the integrity of rig and rudder might lead to take that first reef early if one is engaged in a passage of hundreds or even thousands of miles. Obviously if you are sailing round the buoys just outside your home port you would act differently.
    As for dropping the genoa at sea in 20 knots and above, I agree with Tane, I would'nt do it, it would not be my choice, unless I had to.
    Fair winds :)
     
  13. philSweet
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    philSweet Senior Member

    @Tane, I have a catalina 38 with a 690sqft 160% genny that weighs about 75 pounds. Yes, it takes a while, like 45 minutes, but I do this rather than fight a miserable sail set for a day.

    There is also the option of furling the sail, and hoisting a specially made sail over the furled sail. ATN's Gale Sail is one example.

    http://www.atninc.com/atn-gale-sail-sailing-equipment.shtml
     
  14. gggGuest
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    gggGuest ...

    A decent polar diagram ought to be including "leeway".

    Personally I don't much like the term. In all sailing craft lift produced by the rig from the air must be balanced by lift produced by the hull/foils from the water. In craft without adjustable underwater foils "leeway" is simply the angle the hull must take up in order to provide the required amount of lift.

    So yes, if the boat has rather more drag than it ought then it will be going more slowly, and if its going more slowly the hull will generate less lift, so in order to get back to the required amount of lift the hull must be at a greater angle of attack = more leeway.

    An interesting exercise, should you have the facilities, and these days a smartphone should do, would be to look at the speeds on the polar diagram, and try sailing as high as you can whilst maintaining those speeds. A GPS logger on the phone would then be able to track the real numbers and compare to the polar.
     

  15. Alby1714
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    Alby1714 Junior Member

    gggGuest,
    A polar diagram reflects only the computer model that has produced the diagram and its quality, i.e. how good the model is in representing the true characteristics of the boat. Unless otherwise specified a polar diagram gives the speed through the water for a given true wind speed at a true wind angle, and normally, again, unless explicitly indicated, it assumes the most favourable conditions in terms of boat load, sail trim, sea state etc. This is hardly surprising as polar plots are provided by designers/manufacturers.

    Additionally, I understand, (please correct me if I am wrong), that, because of the way a polar diagram is built, it cannot say anything about leeway.
    By way of example, assume that the computer model expects the boat to be able to travel (speed through the water) at 10 knots with a true wind angle of 45 degrees. The point corresponding to this boat speed and true wind angle would be plotted on a line originating from the centre of the diagram (the "pole") and tilted at 45 degrees from the vertical line passing through the pole, at a distance from the pole equal to 10 knots according to the scale of the plot. That means that the vertical line represents the true wind direction.
    With simple trigonometry it is therefore possible to calculate the component of the boat speed along the vertical line i.e. the VMG to windward. However the true VMG is affected by the leeway and is certainly lower than the value that can be derived from the polar diagram using simple trigonometry. Stated in a different way: polar plots assume "0" leeway. I have never seen a polar diagram offering in whichever form any indication of leeway. If you have, please let me know.
     
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