I have seem more boats showing up with mid-boom sheeting systems for the main, mostly on A-cats, but a few F-18's also? What, if any, advantages are there to using this vs. the traditional system? Are there greater benefits for buoy or distance races? Do any classes outlaw it?

Capricorn offers the option for teams that have crew handling the mainsheet upwind. My skipper has asked me to set this up on my boat for F18s in Pensacola.

any links to good pics of the set up?

None of the Hobie OD classes allow it - but a Tiger racing as an F-18 could. The round boom on the Tiger isn't strong enough for it, but you could do it with the old, rectangular boom.

Page 19 of the owner's manual HERE.

The Tiger boom and the Cap boom look to be pretty much the same tubing, Matt. Just different colour anodizing.

One thing that I discovered with the mid-boom sheeting on my a-cat is that it allows you to trap out fully extended even when sheeting hard. If you watch your crew sheet from the wire while in the middle of the boat, they have to lean way forward or go starfish to counteract the sheet forces trying to pull them back. It's also easier to maintain your footing with the main pulling you straight in on the boat.

My a-cat has both mid-boom and mid-trampoline sheeting...that is I have the option of grabbing the mainsheet at a block in the middle of the trampoline or at a block in the middle of the boom. I like the angle to the trampoline but it feels spongy...and I ask myself why have an $80 non-stretch mainsheet if you're sheeting point is the middle of the trampoline?

I was going to ask you how that mainsheet was secured on the trampoline, but it doesn't sound like it's kind of just attached there...

I remember seeing the center sheeting on someone's M20, but can't remember how they worked the lower blocks...

I can't speak for the Marstrom, but I have two round plastic plates that are sewn into the trampoline - one above and one from below. There are a series of holes around the perimeter of the plastic plates through which thread is run to attach them. An eyestrap is bolted through both plates and it secures a ratchet block on a stand-up spring. However, I'm going to relocate the ratchet block to the boom to replace the standard idler block and put the idler on the trampoline...this way I can sheet from either point and still get some ratchet action (I don't have a cleat and am slowly getting used to it).

My experience is with the marstrom center sheeting tramp system On a sloop rigged Tornado... it is by far the best system for the reasons mentioned. It had foward and aft cleets in the casting for up and down wind. The tramps were heavy duty and tightened to be really firm. Most of the T sailors seemed to move away from their center sheeting to a rear sheeting system when the chute was added. On the deck it was a bit in the way with a chute and you could kick it out of it's cleat in a jibe.

Mounting the cleat on the boom for a spin boat would solve the room on the tramp issue however I am not sure how you would cleat it or release it down wind in breeze when you would be on the back of the boat.

Many of the A cats are using the ronstan flip flop ratchet block with cleat on a carbon 2 inch boom. You flip the rails and it cleats forward. It's great up wind since you hand hold it most of the time but you can cleat it forward to make adjustments or tack. Down wind the sheet is foward of your body and you can look foward, drive and sheet without turning into a pretzel, you don't cleat it doing the wild thing.

I was going to switch over to mid-boom sheeting about 4 months ago since my crew comes from the 505's and thats what they all have. However Mike Krantz does not believe that the boom on the N20 could support the new side loading that you'd put on it. Even the older rectangle boom.

I'm not willing to try on my boom thats for sure. It's already bent just from regular sailing.

The most load the center of the boom will see is as hard as you can pull on the sheet. All the high stresses will still occur at the back where the purchase is. I'm certainly not one to question Mike but I bet you would be perfectly fine with center sheeting on the rectangular N20 boom (but definitely not the round one).

I'll be more than willing to try....

if I could source a new rectangular boom in the event mine broke. I'm not a fan of the round tube boom.

Even on my Paper Tiger and hiking only the mid boom angle was much better. The PT runs an alli box section fore/aft under the tramp. Almost no weight and stops "sponge". Also, sheeting direct from ratchet on boom is great as an alternative. This means the main is ALWAYS hanging in front of your face and you NEVER grab the sheet in the wrong place.
I think it is important to remember that a lot of what the tech side of sailing exhibits is fashion rather than the "last" thing...and once other parts of the formula change what was the best idea can become out dated.

Harden up and go for the speed, sleeve the boom with carbon or alli if you are allowed to and are that worried. Innovation wins.

I think I need to do this on our 18 hybrid so I can sheet the main comfortably as crew. Recommendations on gear? Need to start w/ a boom...

Has anyone tried running the mainsheet forward along the tramp to a mid-point or further forward turning block/flopper with cleat? This would not change any loading/bending on the boom as force is still from the usual place, but sheeting angle to the crew would now be square to the hull. And there is no line coming down vertically to the tramp from mid-boom point, creating interference issues during tacks/gybes.
Tramp tensions might play a part in sheeting performmance...perhaps running non-stretch vectran/spectra under the tramp to the corner beams and/or gunnwales to take loads might cure it?

Mike.

There's a few threads on this in other sections covering this on specific classes.

Our boat have always had the centre sheeting option (coming from the A class) and I have always used this system and swear by it.

On the CAP we have 2 different boom sections to deal with the mid loading. But just like Jake said it is no more that you can pull (this is little over 50kg). Most of the load is still at the end of the boom.

The tramp reo is some heavy Dacron sewn to the underside with some over sized washers on the block saddle.

it's a pretty easy system to set up... figure out where you want the block on the deck, find a good sail maker to put some reinforcing patches into the tramp. Measure the distance from that to the mast base. That will be the the distance from the goose neck to the hanging block on the boom.

I'll see if I can find some good images of it and I'll sketch it up if you guys want.

Actually I think the Hobie Class does allow it. We went through this drill at the Hobie 16 NA's in Rhode Island. One of the competitors had a sort of mid-boom sheeting that was closer to the gooseneck than mid-boom. At any rate, we wanted to make sure it was legal before racing started so we looked into it quite a bit. It was decided to be legal at the time.

14. BOOMS
14.2 Boom bales for the purpose of hanging mainsheet
blocks may be added, deleted or relocated.

16. EQUIPMENT
16.4 Main, boom and jib sheet blocks of different design
or make may be used provided the purchase
advantage remains equal to or less than
7:1 on the mainsheet system and 3:1 on the jib
sheet system unless specified otherwise in individual
boat class rules.

Thanks,

I am aware of the usual setups for mid-boom sheeting. My question is whether anyone has considered just running the mainsheet forward along the tramp to a turning block and out to the crew. Not down from the mid-boom to the tramp. I don't like the thought of having a vertical in the middle of the tramp to get in the way during tacks/gybes.

Yes Mike Krantz has done this on his A-cat. I was considering doing it for the Tybee this year but didn't get the expenditure passed thru the war department in time to get some decent practice with it.