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MPS or Gennaker Trim


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We used the MPS (do they still call them that ?) last Sunday, it was a broad reach and it would not set  presumably because it was blanketed by the main. The boat is masthead rigged and the tack was attached at the base of the pulpit, the boat not having a prod. The week prior we flew it with the wind just aft of the beam and it set perfectly. If we are not to fit a prod is the answer to use the spinnaker pole ? This would sort of defeat the purpose of an MPS for me, the sail is made by the Willis loft and its had little use so its mint, any suggestions ?

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A real MPS (multi purpose sail/spinaker) is nowhere near as versatile as a proper gennaker - Like an A2.

MPS is like a motor sailer - not great at either job.

An A2 will go from about 165 right around to about 70 deg apparent.   Neither sail works if you are really deep, then either take the main off, or use a pole (or a real Spin...)

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If you are set up with a tack line to your MPS, you can ease it a bit, this lets the luff roll up a bit, by easing the sheet as well it can all roll out to windward a bit, which will help (a bit). Short story though, is if you are too deep, the sail gets blanketed too much by the main, and, if you are too slow (which you will be if the MPS isn't pulling), then your apparent wind drops, and nothing works.

Probably the easiest thing to do is to come up (heat it up) until the sail is drawing well and you have good boat speed, then soak back down as far as you can while still keeping the sail flying and reasonable boat speed. The deeper you go (towards a flat run) the slower you will go and the shittier the sails will draw. But yeah, a proper gennaker will handle better (easier) and be faster. As already said, you can sail higher and faster and gybe down wind, just like a sport boat, or run a spinnaker on a pole, with all the incumbent pieces of string and what not.

 

I also run a gennaker off the bow (pushpit) but I got a proper one made and ditched the MPS I had, it was like trying to sly a brick...

Gennaker off the bow is nice and easy short handed and cruising. Spinnakers are faster, but a lot more work.

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Thanks for the help,  all good points, we are still figuring out the boat and rig so we will continue play around with it.

Setting it with a pole would be worth the hassle on a longer trip like to the Barrier etc.

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What sort of boat Frank?

Sounds very much like our learning process with the Davidson 28 and our old MPS. All the above advice is good, especially not running too deep downwind, and easing out that sheet as far as you can without the forward edge collapsing. It is very easy to end up oversheeted after it flaps a bit and you correct.

We have also started adding a second tack line tied to the windward rail so we can haul it out from behind the main a bit, but that's a hack.

Ultimately we are now setting up a proper symmetric spinnaker as it can get so much more sail out downwind, and in a boat like ours we don't have the apparent wind speed to rely on.

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For wind range in light air I can usually run it around 80 - 150 degrees apparent, less if I'm not paying pretty close attention to it. Bring tack line in tighter to sail high, ease our a foot or two to sail deep. Keep easing that sheet.

It's definitely happiest on the beam but then isn't everything?

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Chrs, ours is a heavy boat so there is probably little or nothing to be gained from sailing anything other than a direct course downwind . That said, it it is a stiff boat and happily absorbs the power of the MPS which is broad shouldered and seems vast when set (masthead rig) . It has a sock so is easy to deploy and so long as it is not blanketed it sets well and seems very stable so we will use it when the situation suits, probably on the longer passages like a SW to GB. The boat is a Hood 38 

https://sailboatdata.com/sailboat/hood-38-wauquiez

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1 hour ago, Frank said:

so there is probably little or nothing to be gained from sailing anything other than a direct course downwind

Only if that's your destination, try going somewhere else and your Gennaker might surprise you.

Some Gennakers will happily sail wing to wing with the main, if you really must sail DDW then its a pretty handy option.

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Here are a few pics of the D28 for comparison. Note these are not all on the same day, though it's fairly similar light shifty harbour conditions which we often end up sailing in.

I'd be keen to hear any suggestions on trim, anything you'd do differently, and any thoughts on what a more modern sail shape would look like in comparison.

IMG-20200621-WA0005.jpg

IMG-20200621-WA0001.jpg

IMG-20200621-WA0000.jpg

IMG-20200621-WA0008.jpg

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When reaching with this sail I would play around with strapping down the sheet so the turning block/point  is much further forward rather than running it all the way aft

You can do this simply by just tying an open loop around the sheet and strapping it to a genoa car or any handy tie point that is strong enough..Lead it aft to a cleat in the cockpit and then play around with the tension. I'm no sail trim guru but this always seemed to make quite  difference on my old boat,.

I think this is called a barber hauler but the racing experts might correct me on that.

 

https://www.mysailing.com.au/news/barber-haulers

 

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Looks to be a lot of opportunities for more sail area at the foot of that sail

a full hoist sail would give maybe a third more power down low where it’s of the most use

jmho 

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Could you set a symmetrical the same way as the MPS on the Davidson above?

What are the fundamentals for flying a symmetrical as a 'tacker'

I don't want to scare the crew (First mate) with all the pole work and don't want to buy a new asymmetrical.

The two scenarios. A tacker which is fundamentally flawed and therefore a bit of a b*#ch, and a new asymmetrical that will be used once.

I am planning to try the 'tacker' on a still summer's day with a Second mate. Just wondering what to watch out for?

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53 minutes ago, Plato said:

Could you set a symmetrical the same way as the MPS on the Davidson above?

In light wind as the wind comes forward to the beam (and maybe a touch higher depending) you can move the pole forward and dip it down a touch to flatten the luff. At that point you are very close to flying the symmetrical tacked down as like an asym. It is unlikely to go as well as a gennaker cut for that purpose though it will depend on how the sail is designed as there are different variations on spinnakers.

The symmetrical spinnaker we fly on the Davidson above is a much fuller cut with big shoulders up high. That's a lot of sail hanging out the leeward side in a less than ideal shape. It is really designed to fly symmetrically in front of the boat in a big full "bubble" shape. This is a pic of a Cavlier 28 which is the same hull as the Davidson above:

 

ACtC-3dRvCw4LCwakfLZTTNYSIZTXc1FbFem_D52

All that said, there's not too much you can do wrong if you choose a nice 5kt summers day and give yourself plenty of space, try it out! We've have on occasion run the MPS on a pole like a symmetrical as we didn't have another sail on board. It looks stupid but if you really need to get downwind it works-ish.

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