Chainplates very close to the gunwales, big issues with sheeting a genua?

[halfmanhalfboat]

Hi!

Our Compis 28 has a lot of space outside of chain plates. It is friendly for sheeting genua to a quite laterally placed track. When we fly an inner staysail, having a cutter configuration or a stronger upwind we sheet it on the inside of the shrouds to another track closer to midline. These sails do not reach to lower shrouds, no issues. Otherwise we sheet also the staysail on the outside of the shrouds if not pointing high. It works very fine.

I can see many boats having chain plates placed very laterally, sometimes on the outside of the hull. Lower shrouds are crossing the space where a genua clew and its leech is to go. Is it a no go situation for any bigger genua? We have always been planning to change a boat for a bigger one. Now we wonder if we should consider lateral chainplates a disadvantage?

Thank you very much for your help,

[GordMay]

Greetings and welcome aboard the CF, halfman.

[Sailmonkey]

You can certainly use a larger Genoa, just be prepared to loose the ability to point as high as before.

[Cheechako]

On a cruising boat I have never been able to really point high anyway without losing a bunch of speed. So outboard has always been nice for me. Better to keep the stick vertical too! But it sounds like you are used to running the sheet inside or out, so I don't see an issue with outboard chainplates...

[halfmanhalfboat]

Thank you very much for all your answers!
It looks like nobody really hates outboard chainplates. I probably should not either. Or maybe someone actually does?
Spontaneously it looks like not only genoa sheeting but also walking upright is more challenging with them, isn't it a little?

[01kiwijohn]

My Cascade 36 has chainplates at the gunn'l. It took me a long time to realize that I could get better performance by not trying to sail above its' designed sailing angles. The message was driven home, when sailing back from Hawaii, as I cracked off a few degrees and noticed (on the plotter) that my increased speed gave me far superior performance with less leeway and a nicer ride. AKA "Free Lunch".

[guyrj33]

When i'm flying the 155% sheeting to the rail works fine and the sail can be trimmed to touch the spreader tip.
When i'm sailing with the 125% sheeting to the rail at a point farther forward and thus farther outboard I can't point as high as I can with the 155.

i'm going to install inner tracks over the winter to address the problem.

So I guess it it depends on the individual boat and the cut of the sail.

[billknny]

Tighter sheeting angles can help a boat point higher, but only if the hull and keel can resist leeway.

My boat has a pretty wide sheeting angle, about 18 degrees. If you move it inboard from there you end up with the sails drawing well, and it LOOKS like you are pointing higher, but the keel is fairly wide and it stalls, and you are sliding sideways so fast that all benefit has been lost.

In very broad brush terms, if you are not trying to point really high, the outboard sheet attachment will give you marginally better sail shape, with less twist.

Just another comment, it can be really hard to know what angle give you the best VMG. Typically it is quite a bit tighter than where your speed starts to drop off, but without careful steering and well calibrated instruments it's tough to be sure.

[halfmanhalfboat]

Three of you are suggesting not to struggle for a tight sheeting and a high pointing anyway. Billknny provides yet an attractive theory why not with the keel stall phenomenon. Is it more pronounced with long shallow keels or is it relevant even for fine deep keeled ones?

[MartinAdelaide]

My Austral 20 is the oldest of the four at my yacht club and has the chain plates just in from the gun'l. On the other versions, the plates move further in and the jib/genoa track moves inward too. The difference is, at most, 2 inches but I suppose they point a bit higher. For my part, I prefer walking inside the rigging when on deck. p.s. It's not that boat on the left.

[waterman46]

Originally Posted by halfmanhalfboat

Thank you very much for all your answers!
It looks like nobody really hates outboard chainplates. I probably should not either. Or maybe someone actually does?
Spontaneously it looks like not only genoa sheeting but also walking upright is more challenging with them, isn't it a little?

It is not a matter of love or hate, it is a matter of what type of boat design you want for your own purpose.

You won't find many racing oriented designs with external chainplates for the sail trimming reasons you already are aware of. Actually the limitation is usually at the spreader where the genoa will be closest in contact to the rig.

I think there are lots of advantages of chainplates mounted outside the hull, often called external chainplates, but mainly for true cruising boats that are not optimized for upwind performance. In these designs, a very close sheeted genoa will not improve on VMG to weather.

It makes a more robust mechanical design to have the shrouds outboard. No chance of deck leaks that over time can rot out the bulkhead below. That bulkhead is only attached to the hull interior by fiberglass tabbing, which can fail over time as the hull flexes. Or it will lift up against the deck and you will have a "hard" spot in the deck flatness, possibly cracks in the gelcoat. Since the shroud is farther from mast with external plates, you have proportionally less stress on the shrouds due to the wider angle from the mast.

Your thought about walking the deck being easier with inboard shrouds is true if the boat is heeling much. Another example of cruiser vs. racer mentality. Cruisers avoid heeling like the plague, not only for comfort but because the typical cruising design does not sail well to weather with very much heel. Keep it flat, then you will be walking inside the outboard shrouds, where you are much safer anyway.

[halfmanhalfboat]

Our warm thank you to all of you who answered our question! We have learned a lot!