I finished the radio install and sails and headed for a lake this afternoon.
Despite closing the hatch with masking tape and dangling the antenna along a sponson rod, it sailed pretty well. Lousy lake for sailing as water weed caught in the rudder every 20 yds. and the winds were very light.
Nevertheless, it sails and breaks down easily to fit in the smallest car.
Is there a good site on boat/sail trimming (or even basic sailing instructions)?
:zbeer:
Nice job Glen - looks good on the water.
I would think there are a “ton” of on-line basic sailing instructions.
Did you download the US1 Meter Contruction Guide? While it is a monohull construction info - near the end is a basic sailing article.
There are a few hints/tips for a multihull that differ from a monohull, and the main one is to keep watch. You aren’t on-board, and can’t feel the windward hull when it gets “light” in a wind gust. Have a thumb on your sheeting stick so you can dump sial area if it starts to go up. Also keep in mind which way to move controls to keep the sial area at maximum and minimum area exposed to wind.
Downwind - deep reach is faster than dead-downwind.
More later unless you have some specific questions.
Dear Glen,
congratulations to your successful maiden voyage - the boat looks great on the water.
Cheers
I got to sail it in stiffer winds this morning and learned a bit. I couldn’t tack at all and had to jibe to move upwind. I wasn’t easily able to beat upwind but improved with practice. Te CG is too forward and I’ll be moving the batteries back. The sails need better tying with better line that can be tensioned properly. Sail trim will be a future topic of study and experimentation. FAST!! and I was able to get it up on one sponson for a few seconds and didn’t dump it over once. I can see that if I get the sails dialed in its going to be a thrill to sail.
Glen Byrns
:zbeer:
Hi Glen,
your CG should be at about at middle of the center board. This is 240 from transom on mine. If CG is to much forward the boat will be difficult to tack. Please post some pictures of your current config, maybe I can give you some tips how to trim.
Cheers
Phanchita:)
I got the cg to the middle of the centerboard by moving the batteries back. I attached a few shots of the rig.
What adjustments most affect the angle the boat can achieve into the wind?
Thanks,
Glen Byrns
Dear Glen,
hard to see on the pics but it looks like your jib is hauled too close . Try adjust the jib boom opening angle to something between 5 - 10 deg.
Cheers;)
Glen -
unlike the monohull “brothers” - a multihull has it’s own sailing characteristics which differ slightly from the boats with lead keels.
While much slower, the lead provides a bit of momentum to allow a monohull to glide through dead spots with little/no wind, and it helps them tack. Also a factor is they have one hull - you have two or three that must pass the eye of the wind. Thus making sure you have a good head of steam before making a tack is critical.
As you approach the point where you want to tack - foot off a bit to gain speed. As you start your turn and the jib crosses the wind, let your sheets out slightly and bear off well below your intended point of sail. Once you are moving and water is flowing past your rudder and daggerboard, SLOWLY inhaul you sail sheets. Too fast and the boat will respond by heading directly into the wind - and into “irons”. As you slowly bring your sails in on your new tack, you can also start to head up towards the wind.
Multihulls won’t point quite as close to the wind as a monohull - but that’s fine, since they have much more speed and can cover greater distance in same period of time - so don’t “pinch” - bear off (footing) a bit to keep up your speed. It provides two things - First you are going faster, and can “bang corners” before having to tack. Tacking is slow, so don’t try to get into a tacking duel with a monohull, and if you try against another multi, experience will be a big help. You don’t want to blow a tack during a leg of the race as they are hard to recover from. Second - the faster you go, the more the apparent wind shifts forward. This seldom happens on most monohulls - but on multihulls and ice boats, you may see apparent wind speed 1-1/2 to 2 times stronger than the real wind, and it keeps trying to come from in front of you. Thus, you can steer away (slightly ) from the apparent wind, and because you are on a close reach, you are now sailing even faster. Remember - there is no theoretical “hull speed” like on a monohull. You are usually only limited by hull/appendage/sail area drag.
To help you sail closer to the wind, try to have a bit of weather helm which lets the boat “seek” a higher sailing angle (tilt mast aft a little bit). Likewise - downwind - gybe and reach - don’t run directly down wind as once again - gybing and deep reaching will result in your speed being slightly faster than true wind.
Above all - don’t let go of your concentration to look at the bikini clad women, or search around for your bottle of “adult beverage”. Too easy to be distracted and a sudden gust when sailing on the edge of control may find you doing a boat rescue! Keep the thumbs on the sticks. If small gusts, head up slightly into them on a beat. If a big gust, sheet out and foot off for more speed. Playing these two techniques will help you maximize your upwind speed and get you to the weather mark quickly.
Good luck and enjoy - it’s a completely different ball game than monohulls and with slightly different skills. Just don’t try to pinch up - foot off for speed, sail to the layline if you can and take one tack to bring you in on the weather mark.
Dick
“Starboard is always right”
Something I remember from a bit of sailing in a Hobie 14 is that if you’re headed upwind and it looks like a gust is going to push you over, it’s better to bear off to recover instead of heading up as you would in a monohull. I don’t know if this applies to a model. Easing the sheet still helps, of course.
I don’t know what class rules you have, but I wonder if a so called jib twitcher wouldn’t help with the tacking, so you could hold the jib backwinded until you come around. Also, if it starts to go backwards, the rudder will work in reverse.
Ummm - my motto was “Down is Down” - meaning if you are beating to weather - and turn down, away from the gust, you are providing a much larger sail area to the wind, than if you feather up and into the wind, which reduces sail area exposed directly to the wind. You might have to play with a drawing on paper to be convinced of that one. Likewise on a deep reach, if overpowered you will sheet in to bring the leech of the main sail in line with the wind rather than perpendicular to it.
Footing off in a gust is an alternative - just depends on strength of gust - and how long it lasts. If short duration, footing off and easing main will add a lot more speed, and then sheet in after gust passes and work back up to weather. Major problem is you aren’t on the boat and can’t feel the weather hull(s) getting light. Not much time to plan - only react.
Twitcher is legal - but Glen is sailing a swing rig, and also boat is only 25.5 inches in length making additional radio gear a tight fit. Actually a second servo to control jib is allowed - it’s an open development class - only overall length is critical. If you can fit it in and hold jib over to backwind it I would definitely agree it would be the way to go.
I know the trick with the Hobie works because I tried it. Wasn’t easy to get myself to do it, as it was counter to previous sailing experience with monohulls. I think it relates to the Hobie’s speed. Bearing off reduces the apparent wind, as not as much of the boat’s speed is added to the wind speed. The other effect is from turning. When a Hobie is raising a hull, it’s usually going so fast that it will lean out of a turn just like a car does. And vice versa. One nice feature of this trick is you can do it very quickly, in a fraction of a second.
Now that I think about it, I’m not entirely sure if the trick was for upwind or reaching.
Whether the dynamics with a multihull model are the same, I don’t know.
Thanks for the help guys. Though the sailing specific terms are foreign to me, the hydrodynamics and basic vector physics are clear. I’m not able to carry enough momentum into the tack to succeed. More speed, more weight, or less profile drag would help. I can try to improve the first factor through technique and better sail trimming. I adjusted the sails as per Siri’s suggestion and shifted the CG to the midpoint of the centerboard. Now its back to waiting for wind again.
Glen Byrns
Also - make your tack turns wide and much slower than monohull. If you jamb the rudder hard-over, it will act like a brake - stopping or slowing the boat. A slow curving turn will get you across with less trouble. For the 65 sized class, I am thinking a radius of perhaps 4-6 feet might be a good starting point. In heavier winds try to tak in the flat water between waves. If the angle is to your benefit, the wave action can also help “slap” your bows over to the new direction.
:graduate: TIP: Technique of rudder “waggle” is useful if arriving a few seconds early at the line for the start.
This is a troll thread. It has to be. wow gold buy wow goldcheap wow goldworld of warcraft goldwow gold eu
I finally had good wind today and had lots of fun and learnes a bit. Its QUICK!! It got the main hull clear several times. I got the jib trimmed to get the most speed for the conditions and that made a big difference. With the greater speed I was able to tack sucessfully almost every time. There is a tendency to bury the nose of the downwind sponson when it really gets moving. Would bending the mast back a bit help with this?
Got to say, the speed makes this more fun than I remember having with any of the 2D RC hobbies.
Glen
Well Done Glen !
leeward float bows will have a tendency to (non-sailing term) “DANCE” when off wind. If it is bobbing down then up as you hit waves or when wind gusts - it is the nature of the beast. May be sailing right at the performance “top end” with the sail area if it is under for a period of time. Steering will help a bit and should allow it to “pop” back up - but it may be you are at the limit for the sail area.
I’m not sure what Siri or Disabled wound up with sail area wise, but a percent smaller sail area will help - or keeping same sail area but not so high in the air. Hard to provide exact corrections - or if you even need to worry about it - and kind of goes back to my earlier suggestion to not let your mind wander especially if wind is a bit gusty. If it is stuffing the bow all the way back to the cross-beam, they may have included sufficient bow buoyancy to keep it going and also come up. Driving the bow down to front cross beam was exciting with the big boat, but it eventually came back up - although slowed forward progress due to drag.
Try the steering alternatives first as they are easiest to do. Tipping the rig back seems like it should fix the problem, but will add more weather helm which creates other trim problems. Basically the tall rig and sail area high up is trying to use the mast as a lever to push forward (and down) - if the boat can accelerate you will be fine. In heavier winds you can also try a “T-Foil” rudder with the “winglets” set at about 2-3 degrees negative camber which will (theory) pull/keep the stern down. In light winds and such small negative angle, you should be OK and as wind/boat speed increases, more down pressure on the stern will result.
Dick