square topped hoop

If you have sailed a Laser/GP etc. IMHO it is not much different (i.e you can tack with the tiller extension going forward and past the standing part of the mainsheet when tacking) If like me you have always sailed with the tiller ext swinging around the stern of the boat for most of your life the bridle arrangement is a complete nightmare!
Just my 2cents worth
IanL
Your mileage may vary! 
We borrowed a boat with transom strop arrangement for Salcombe one year - it we OK until we tacked - which was about every 20 sec on the beat - it was a very long arduous Salcombe Week !

i have a square topped hoop on my boat at the minute and find it quite slow to tack.As i tack i let the helm down,uncleat the windward cleat on the twarth for the traveller on the hoop,hop over to the new windward side,pull in the new sheet for the traveller and cleat,then pull in the mainsheet.VERY SLOW!! or maybe its me.I've sailed with a transom bridle and found it easier as the main will always come to the centre.I did find it awkward with the tiller.
What are the advantages of the hoop over the bridle trim wise?

All the boats i've tried with a stern bridle (Not just merlins) are hard to tack. You end up using too much rudder and there is more rope on and behind the boom for it to become entangled with if you don't.

The length necessary for a merlin tiller extension exacerbates the problem.

Dave Fowler likes his stern bridle, and was seen sailing aft main at Earlswood to get around the tacking problem. Being a larger gent i think he feels he needs the room and the hoop gets in his way. He'll no doubt be in soon and will tell you himself.

Square hoops are fine if they are set up properly, and are only marginally slower to operate than any other mainsheet system. It is two operations as opposed to one but it's really not that difficult provided the system works!

I would agree with Chris on all points especially the hoop set up. I remember Laurie Smart fitting a hoop for me on an NSM2 (Galactic Gnu) a couple of years ago, it took him ages to set the tack/cleat release mechanism so that it worked properly and efficiently every time,did a blinding job, though the air was also very blue when I popped up to see how things were coming along!

.........having said all that I will eventually be fitting a stern bridle on 908 'Wishbone' to keep her in keeping with tradition. As I have never sailed a boat with a stern system it should be very interesting!

"Merlin Admirer" says that he first uncleats the windward cleat on the traveller.  This is unnecessary on most Merlins with a square hoop.  There is a short strop underneath the thwart, with loops through which the traveller lines pass.  As the helm pulls on the windward traveller, the strop disengages the leeward one. This means that there is only one extra operation, not two. Also a helpful crew can pull across the traveller, in between all the other things he/she has to do.

The origional system was as he described it though. The auto uncleat came later.

So hard to describe verbally:

this too looked a nifty and effective uncleating system on 3489.

cheers guys,it appears that i have the older system.I'll have to figure out a self uncleating system.I'm still wondering if the transom bridle system is better or are they the same as they both achieve the same result.

Chris is right with the combination main i was overstearing (hand break turns). but I hate the complication of the square top hoop and its complexity, gear failings, and the over centre sheeting angle that i see mon many boats.
I have been using a tail main with twin strop since Earlswood, through salcombe and its still there.
I had forgotten how much more control you have with the transom sheeting, with speed of sheet responce in gusts. no jammer jamming, or having to lean in to unjam the sail??.
You Can check it our at the new inlands.

DaveF

Bridle saves weight, just has a long length of string - but when did that ever stop a Merlin sailor! It also means that the crew has no seat back to their comfy central chair position.

Only downside is gybing as there is nothing to grab - perhaps Dave could elaborate on his technique?

I used to sail Charge with the old cleating system on the square hoop, we had a line going across the boat from one cleat to the other so that you could uncleat it after the tack, though I found that I often uncleated it as I was going into the tack just before crossing the boat without loosing any speed. You can always cleat this system in the middle of the hoop for those short tacking stints, which is impossible to do with the auto uncleat system.

Andy
I have a length of main sheet hanging from the boom (not attached in the boat), just grab and pull, no mess, no getting a bunch of main sheet trapped arround the hoop causing the main to trip the boat over on a windy gybe. the only thing i missed about the square hoop was the zimmer frame effect on very windy run, but without the hoop the crew comes diagonaly back across the boat, and it feels so much more open, not a bad thing for my size.

The idear of the transom main is that your bum and heavy bits are placed in the middle of the boat when you tack.
Some C/main boat classes tack this way for this reason.(less wieght on the transom).

Steve Carbonater Leaney has a short piece of stiff sheeting with a rope stop(one of thoughs roud things with a hole in the middle)at the end, fixed to the end of his tiller extention, this lenghtens the tiller extention but also allows the extention to pass the hoop, ie. the extention goes forward rather than out the back of the boat. 

See it in action at Blithfield this week end.

after sailing the inlands with a square hoop, i'm looking forward to retuning to the transom main.

If you want to tack you would not want to ease the main, rather sheet harder, so do not let the windward traveller go before the tack. Aft sheeting is lighter, simple and cheaper and to a certain extent does the job. But,you cant get the main on the centre line in light winds without applying leach tension which you may not want.

All of which sounds like a great advertisment for a traveller with no hoop!

beg to differ, with the rear strop the main comes in to the desired place just off centre, too many people were stalling the sail by over sheeting on the square hoop, but my main reason was because of the walk round the back of the hoop dragging the transom, and stalling the boat, with transom main you can tack over the middle of the boat smootly, with no massive pump bang some others were doing ( see video of the racing).

I've described before the mainsheet set-up on my brother John's boat Baccarat no. 2614 which I subsequently bought from the late Ken Ellis. She had a conventional track on the thwart but John split the traveller and welded about 2 ft of tubing between the two halves. This wider traveller could be cleated at any position between along the track. A strop went the each end of the traveller up to the boom, allowing the boom to be moved a couple of feet across the boat. Simple, cheap, practical. I sailed boats with after mainsheets and round hoops but for me Baccarat's set-up was the best because the boom angle could be controlled like with a square hoop but in addition it was was user friendly.

I absolutely agree with Robert Harris, this is the arrangement we devised in 1970 for my last Merlin Rocket 2304 there is a picture in the Photos Section of this boats first outing at Hamble in March 1970.

Link

Nobody seems to have taken up Grump's suggestion of a full width traveller (seen in older Merlins and very modern N12s) with no hoop at all. If desired a single strop could come up from the traveller car so the sheet could go "block to block" to prevent over-tensioning the leech. If you really wanted it, this strop could be adjustable in length to compensate for rake in the rig (which cannot be done with the square-topped hoop). The result of this would be very much like Robert's split traveller. The whole affair would still be lighter than a hoop and the centre of the boat would be less encumbered than with a hoop too. It's a relatively simple affair to make the traveller auto-uncleating by using a "too short" line across the boat in the usual way. If you want the option of switching between auto-uncleating and having the traveller fixed in the centre as in Stuart's post then the line can made long enough to allow this but with a hook and loop link to shorten it when the auto function is required. The downside to all of this is that when the traveller is pulled right across, access fore and aft of the traveller is compromised - but isn't that the story of life?

Harken used to do a self-tacking traveller that was used on both Deep Thought and Second Thought. Pricy but it worked.

I suspect the real reason for the hoop, for the majority, is it gives you something to hold onto when gybing - a track and traveller does not!! My daughter used to get fed up with me arriving head first over the thwart as I had forgotten the boat had no hoop!!

I cant help hanging on at times...but if I had never had a hoop, I assume I wouldn't miss it.

Also, I wouldn't have headbutted it that time at Salcombe....hell, that hurt.

I never have been the most agile in any boat, but I do have to say I never felt the need of any support in a Merlin Rocket,(Except possibly a truss after a long max hiking race!)but I was fortunate to always (well nearly always.) have agile and excellent crews who doubtless made up for my lack of fairy footedness.

When the mainsheet is under tension then the centre strops are rigid enough to pull on to haul oneself inboard. Admittedly in the middle of a gybe nothing is under much tension except the helm and crew!

in a boat if you're balanced, then the boat is balanced.