Rounding up all the time

[belizesailor]

Originally Posted by Valmika

I have had the problem of too much jib on a mono digging the leward side of the bow in and rounding up. Never had it on my FP Tobago though. I guess it would be easy enough to roll it in a little more. Personally I'm thinking the props. see if it always turns the same way.

Originally Posted by smj

In post #21 he describes what the problem was and how he fixed it.

Come on...you peeked! 😆

[daletournier]

Originally Posted by belizesailor

Ooops, missed that one.

Me too.

[hamburking]

Do you have excessing windage aft...like a big dodger or arch with solar panels? That could be acting like a sail to push the stern down.

[Tornadosailing]

Originally Posted by hamburking

Do you have excessing windage aft...like a big dodger or arch with solar panels? That could be acting like a sail to push the stern down.

No solar, no dodger, no arch. The only thing I have is the worlds smallest bimini over the helm.

The problem is in the props, and in the end I think more of a learning curve for the boat and the props. The rudders are rather small for a boat this size, but work well.... except.... The boat was built not with the 40hp Volvos but with 75hp Turbo Yanmars, which then gets you a 19 inch 3 blade prop instead of a 17 inch 2 blade. I haven't heard back from Brunton, but my theory is that the big Auto Props *almost* feather when you go to neutral, but clearly still spin. This put a 3 bladed blender right in front of the rudders, with the tips of the blades churning the water a few inches in front of the rudders, and covering the bulk of the rudders top to bottom. This disturbed water flow destroys the lift across the rudders, and effectively means I don't have rudders, and around we go.

[ramblinrod]

Originally Posted by Tornadosailing

First sail in my new to me FP Salina 48 and I'm baffled. I've got some experience sailing a Lagoon 440, so big cats aren't completely new to me, and I can't imagine what's causing this.

I'm out in the Chesapeake right now in about 15kt wind. Main is up on the 2nd reef (it was blowing hard a little while ago) Genoa is at 75%. We're running at about 120 apparent. The only way I can hold my track is with the motors idling in gear. As soon as you pull the levers into neutral, the boat starts to round up. The autopilot can't hold it, and you can't hold it by hand. Put it back in gear and you can steer again.

I'm sure the previous owner had no idea as he literally never sailed the boat. We didn't see this problem on the sea trial because the wind was 1kt. This problem is bad enough that if it happened on the sea trial I would have passed on the boat.

What am I missing?

Are the rudders kicked up for shallow water?

[EWOL Props]

I suppose you have S-Drive transmission, if that is the case props are quite distant from the rudders with low or no effect on those.
I suspect one of the props has stiffer blades for some reason (something entrapped, fouling, else).
Quite a good number of lobster cages in Chesapeake waters and intense fouling also...

[Cadence]

Is it possible one prop is not folding causing the round up as you said. Engaging the engines is causing both props to compensating for that?

[Tornadosailing]

Originally Posted by EWOL Props

I suppose you have S-Drive transmission, if that is the case props are quite distant from the rudders with low or no effect on those.
I suspect one of the props has stiffer blades for some reason (something entrapped, fouling, else).
Quite a good number of lobster cages in Chesapeake waters and intense fouling also...

It does have sail drives, but the props are closer than you think, and are in front of the rudders. If I'm reading the drawing correctly, the design minimum distance between rudder and prop is a mere 152 mm.

https://www.dropbox.com/s/wu48yhdqum...AL001.pdf?dl=0

[EWOL Props]

Originally Posted by Cadence

Is it possible one prop is not folding causing the round up as you said. Engaging the engines is causing both props to compensating for that?

Yes, this is what I think. when the engines turn then also the good working prop takes the position of thrust forward, hence they become balanced

[catsketcher]

It is interesting to know how much our boats need rudders even when the forces should be aligned to make them go straight.

I have towed my cat without rudders - using a line from the bows and the boat was untenable. It was a real struggle to move her about 1 mile. However she is very sweet and never rounds up with her rudders in.

Having your rudders in nice smooth water is really important. It is one of the reasons cats have underhung rudders rather transom mounted ones - to improve efficiency.

I am glad it is all fixed now Tornado.

cheers

Phil

[Greg Mason]

I have experienced weather helm and never pleasant. Does the vessel round up the same direction every time. or choose port or starboard depending on the main? Full batten main or batten slats, so you could luff the main slightly, relieving pressure aft. Others have mentioned moving the traveler car out to sheet in the main, but you say that doesn't help. You have also mentioned sailing ddw with just a jib. Can you sail with just a main? I ended up with a sailmaker on board and eventually raked the mast 14", you always want to try the least expensive things first. I would have guessed the feathering props should have solved any turbulence issues, or decreased them noticeably. Would love to hear the final outcome.

[KP44]

Since it is not too much main, causing weather helm, it sounds more like drag from the props or drag from misaligned rudders. If rudders are properly aligned, you might need folding props to sail. Before even looking at folding props, try to find other sister ships and discuss this with their skippers.

[Amaranth]

Hello Tornadosailing.
Well this has been a fascinating read as I also have an FP Salina with exactly the same problem. And yes I have Brunton Auto 3 blade props as well.

At first I thought I had too much mast rake when compared to another Salina, however I have now ignored this as I have the problem going down hill with just the skreetcher up. I have never experienced a boat that could have weather helm with just a head-sail up!

I thought we had vibration from the long tiller arm effecting rudder performance, so I had a bearing made up to support this mid way along it under the cockpit lazzarette.

I have been looking at rudder alignment and planned to experiment with slight toe in.

I understand what you say about no adjustment in the rudder stock. I was going to make up a plate on the steering arm and have adjustment on this and then attach the cross bar to this and experiment.

I had actually been also pondering to increase the size of the rudders figuring I might have cavitation problems and have been in touch with FP in France to see if
1. They knew of this problem
2. If they had any suggestion of a different rudder shape.
They had no answer to either.

After all this it seems we are both on the same track that it is a water flow around the rudder seemingly caused by the auto props.

I will test #21 in two weeks when back on board and give you my feedback then as well.

Pretty excited after a couple of years of trying to sort this out that I may have been given a straight forward fix.

[Valmika]

Originally Posted by daletournier

Me too.

Me three. I guess sometimes we read the first 10-12 answers and figure ours hasn't come up yet

[Tornadosailing]

Originally Posted by Amaranth

Hello Tornadosailing.
Well this has been a fascinating read as I also have an FP Salina with exactly the same problem. And yes I have Brunton Auto 3 blade props

*snip*

Pretty excited after a couple of years of trying to sort this out that I may have been given a straight forward fix.

I hope this works for you too. I'm looking forward to hearing about your results.