So I've become obsessed with my H-34's balance issue (deep fin keel). Heavy weather helm, etc. This is caused by the moment created because the center of force on the sails is aft of the opposing center of force on the keel/rudder combo. On a well balanced boat like a J-105 these two forces are closer together than on a not so well balanced boat and thus, we get less weather helm. It occurs to me that if I were to build/install a larger rudder it would move the center of force of the keel/rudder combo aft and help to balance out the boat. I realize these centers of force move around depending on conditions but the question is: can I affect the balance this way or is it a waste of time to try. Discuss.
H34 Balance issues
- Thread starter markwbird
- Start date
You want a little weather helm so the boat rounds up to weather when you let go of the helm (more evident with a tiller boat). To decrease weather helm you can rake the mast forward. Or you can reduce sail area in heavier wind situations. The genoa lead can be brought back to spill more wind off the top of the sail. The traveler can be dropped to leeward and you can flatten out the sails and tighten up the boom vang and backstay adjuster when the winds are really heavy.
Yes, proper sail trim is key to balancing the boat and reducing weather helm. This is true for any boat. However, some boats are inherently well balanced and some are not. I would like to improve on the H34 design if I can. Anyone else worked on this problem?
Mark...
The J-105 is a much newer design with a completely different hull shape. Trying to make the H34 behave like one is sort of a fool's errand (I crew on a race-dominating J-boat).
The best you can do is to put someone on the helm that you can trust to be consistant and experiment with all your sail trim variables, one at a time, record what you observe, and begin putting together what works best.
My race captain has a "book" on his J-boat's performance characteristics in all points of sail in many conditions he's encountered. First in class, first overall in this past year's Governor's Cup on the Bay is proof positive.
The J-105 is a much newer design with a completely different hull shape. Trying to make the H34 behave like one is sort of a fool's errand (I crew on a race-dominating J-boat).
The best you can do is to put someone on the helm that you can trust to be consistant and experiment with all your sail trim variables, one at a time, record what you observe, and begin putting together what works best.
My race captain has a "book" on his J-boat's performance characteristics in all points of sail in many conditions he's encountered. First in class, first overall in this past year's Governor's Cup on the Bay is proof positive.
Yes. I will never get it to perform like a J-105. I used the J-105 as an example for comparison to perhaps learn something about what make a boat well balanced so that I can determine what can if anything be done to the H-34 to improve the balance. Specifically: Will a larger rudder improve the balance?
Nevermind the J-105
OK, forget the J-105. Forget the H-34 for that matter. The real question is: will increasing the size of the rudder improve the balance on a boat that tends to round up a bit too easily by shifting the center of resistance aft?
OK, forget the J-105. Forget the H-34 for that matter. The real question is: will increasing the size of the rudder improve the balance on a boat that tends to round up a bit too easily by shifting the center of resistance aft?
No it won't, the problem is in the relationship between the sails and the keel.
Also as the boat heels it no longer makes a symmetrical hole in the water which adds to the tendency to round up. If it has too much weather helm then adjusting the rig is the solution.
As alluded to above some weather helm is desirable especially at large angles of heel.
OK, now that you've forgotten about the J-105...
This is a good idea. Another one is to learn how to balance your sail trim with an autopilot. I've found that aps are one of the best ways to teach good sail trim. If the ap isn't overpowered, the trim is good...
Over the years kloudie1 has commented on H34 sail trim and weather helm. You could do a search...
Markwbird, did you mention what year your H 34 was? If it was a 1983 or early 1984you may recall that these were produced with a smaller rudder. This is made larger by design in 1984 and had carried out through the entire run when they stop producing them in I believe 1988. I noticed some of the balance variation with my H 34 as well which is a 1985. Something I also also found interesting was that due to a winter freeze I lost my rear freshwater tank… A little water remaining in the bottom froze and blew out the bottom of the tank. As a result I sale with about 200 pounds less ballast in the rear of the boat. It actually seems to make a difference… A disadvantage. Those are my two cents… Good luck with things!
Thanks, Stu...
The idea behind a person at the helm rather than using the AP is that the person can give immediate feedback on feel as a change is implemented.
I single hand most of the time using the AP as helmsman while I make trim changes. It's not until I take it off that I can feel in the wheel what the effect has been.
The idea behind a person at the helm rather than using the AP is that the person can give immediate feedback on feel as a change is implemented.
I single hand most of the time using the AP as helmsman while I make trim changes. It's not until I take it off that I can feel in the wheel what the effect has been.
balance issues
I have not tried taking out some mast rake (tilting forward) but I intend to. Perhaps this is all wishful thinking. The boat is tender and I sail SF Bay so it gets a bit squirelly at times. The answer may just be sail trim and seamanship. In particular, when on a broad reach in heavy air the boat will round up. In fact, she can be difficult or impossible to steer back down to a broad reach. This is confounding because there is very little heel when this happens so I have full rudder in the water. And, yes, I have the big rudder. What is the answer here?
I have not tried taking out some mast rake (tilting forward) but I intend to. Perhaps this is all wishful thinking. The boat is tender and I sail SF Bay so it gets a bit squirelly at times. The answer may just be sail trim and seamanship. In particular, when on a broad reach in heavy air the boat will round up. In fact, she can be difficult or impossible to steer back down to a broad reach. This is confounding because there is very little heel when this happens so I have full rudder in the water. And, yes, I have the big rudder. What is the answer here?
Mark...
I've found that reducing the headsail exposure (rolling it up some) helps reduce the tendency of the boat to want to round up (I fly a 110 on the furler). This is especially true if the genoa is larger than a 110.
The center-of-effort is moved forward and offsets the main's, which needs to have the traveler set to leeward to curve the main's sail top to present less sail to the wind, thus lowering the center of effort, allow the boat to sail more upright.
I've found that reducing the headsail exposure (rolling it up some) helps reduce the tendency of the boat to want to round up (I fly a 110 on the furler). This is especially true if the genoa is larger than a 110.
The center-of-effort is moved forward and offsets the main's, which needs to have the traveler set to leeward to curve the main's sail top to present less sail to the wind, thus lowering the center of effort, allow the boat to sail more upright.