Another stability question

[fxykty]

Originally Posted by chrisr

i think the trend on both monos & cats towards sailing under headsail alone is because of the furler it's easier to roll in / roll out, than to set / reef / drop the mainsail.

on the other hand boats with in mast furling like us actually find it easier to set the mainsail as it rolls out / in at the touch of a button, rather than having to pull one of those nasty ropes...

cheers,

You can see many of the new cruising cats being designed lately with masts much further aft, with short booms and large fore triangles. The large racing trimarans and even monohulls like Volvo 65s also move their masts back and mount multiple furling sails in their larger fore triangles. Not optimised for upwind, but still works. For cruising, furling sails are easier to manage, and in the case of a furling main, only if it doesn’t drag on the shrouds when eased.

For the OP’s original point, in 15 knots average upwind we would be reefed for 25 knots, which offshore would cover the expected gusts. But remember that reefed sail plan has about a 100% safety factor, so reefed for 25 knots provides gust safety to 50 knots. And that’s only static stability. So you can generally relax inside in anything other than very gusty conditions or environments in perfect safety.

As others have pointed out, there are several things to do with sheets and course depending on your wind angle that will increase stability.

- If close hauled, turning upwind to feather is OK, but ONLY if you are already hard on the wind. You quickly reduce the power in the sails, but increase the apparent wind and the turning force will be working to lift the windward hull. This effect is why racing cats capsize on close reaches when driven by sailors who are more familiar with monohulls.
- If 40 degrees apparent wind angle or more, turn downwind. As pointed out, this has two benefits: acceleration reduces apparent wind (increase) and the turning force pushes the windward hull down. Bear off quickly to 150+ degrees apparent, straighten out, then hang on until the gust passes. For those thinking this risks driving into a gybe, you haven’t sailed a larger (non-beach) catamaran: cats are very stable turning and downwind and track like on rails - broaches are not a problem.
- The other option when between close hauled and 90 degrees apparent wind angle is to dump the jib and main sheets. Sheet clutches should ALWAYS be open, and a reverse wrap placed on every self-tailing winch so that the sheet can be released by pulling. This won’t work if the main is already on the shrouds. We do this and lead the sheets to the centre of the cockpit where they are easy to reach even from inside the salon.

[Naughty Cat]

Good tip about the reverse wrap. I'll start doing that.

[mikedefieslife]

Stability is simple. More weight equals more stability, as does a lower COE, and so too a wider beam. Dynamic stability is just takes static suability and multiplies it by 0.6.

As for popping down below to use the heads, make dinner etc.. use alarms. Wind speed, wind shift, XTE, etc.. If it's already blowing 25knts and you have two reefs in. You can always stick another in, before going in.

I said single handed and always have wind speed alarms on. Normally they aren't needed, as I can see the a squall coming, or expect the wind to pick up later, but sometimes it ever so slowly creeps up on you. For my boat I set the first one around 18 knts. I don't necessarily react to it, it all depends on the sea state.

I lot of the posts here talk about releasing the main, but isn't sail plan design going back the way of more aft-set masts and larger genoas? Not as extreme as my old, but for sure Lagoon has been moving the mast more rearward again. So that leaves smaller mains and larger genoas.

[RoadRacer]

Great discussion and inputs from the resident cat owners! I often run the mental exercise and visualize 2x wind speed impacts on my point of sail. I do leave a reverse wrap on the main sheet winch as a quick emergency fuse. My boat (L42) has significant weather helm with a it’s set back mast and tends to be more inclined to head up than fall off.

[Naughty Cat]

Our first wind alarm is normally set at 15knts true. We don't have (or at least haven't found an apparent wind alarm on the Triton displays). Above that it is harder to get the gennaker in. The alarm is shrill, can't be ignored, and combined with the autopilot gives you the best part of an extra crew member.

[fxykty]

Wind alarms? Seems like an excuse to not pay attention to conditions when on watch, weird. If wind is slowly building, surely you’ve noticed (if paying attention). If a gust or squall, too late if you’re not already at the sail controls.

Our PO did a lot of single handing and added instrument repeaters in the salon; if inside during the watch those repeaters and/or the chart plotter are visible. This allows us to not worry too much about spending a bit of time preparing food or doing some chores or recreation, but still not an excuse to not be fully on watch for more than a few minutes. YMMV

[mikedefieslife]

Originally Posted by fxykty

Wind alarms? Seems like an excuse to not pay attention to conditions when on watch, weird. If wind is slowly building, surely you’ve noticed (if paying attention). If a gust or squall, too late if you’re not already at the sail controls.

Our PO did a lot of single handing and added instrument repeaters in the salon; if inside during the watch those repeaters and/or the chart plotter are visible. This allows us to not worry too much about spending a bit of time preparing food or doing some chores or recreation, but still not an excuse to not be fully on watch for more than a few minutes. YMMV

No different from having an alarm. Think of the alarm as a poor mans repeater. I bet you don't have repeaters in the head though.

I'm also not sure the repeater is as useful for the single handed sailor on long passages.

[fxykty]

Originally Posted by mikedefieslife

No different from having an alarm. Think of the alarm as a poor mans repeater. I bet you don't have repeaters in the head though.

I'm also not sure the repeater is as useful for the single handed sailor on long passages.

Repeaters are completely different from alarms, as they have to be watched to provide any value at all. Hence their use does not encourage tuning out. An alarm OTOH may encourage tuning out as it can seem to replace paying active attention.

Correct, no repeaters in the head or anywhere else other than the salon, EXCEPT on every phone and tablet. That is a “poor” person’s repeater, and portable to boot.

Repeaters are very useful for single handlers as they can allow for environmental awareness without full wakefulness; e.g. sleeping in the salon, waking just enough to view the current conditions, then drifting back to sleep. Alarms do have a use for single handlers as they operate regardless of state of wakefulness. But single handing is a special situation that results in periods of no on-watch person; not something to emulate.

[mikedefieslife]

Originally Posted by fxykty

Repeaters are completely different from alarms, as they have to be watched to provide any value at all. Hence their use does not encourage tuning out. An alarm OTOH may encourage tuning out as it can seem to replace paying active attention.

Correct, no repeaters in the head or anywhere else other than the salon, EXCEPT on every phone and tablet. That is a “poor” person’s repeater, and portable to boot.

Repeaters are very useful for single handlers as they can allow for environmental awareness without full wakefulness; e.g. sleeping in the salon, waking just enough to view the current conditions, then drifting back to sleep. Alarms do have a use for single handlers as they operate regardless of state of wakefulness. But single handing is a special situation that results in periods of no on-watch person; not something to emulate.

I understand but the conversation was about someone making dinner or going to take a ****. Even having a nap (as a solo sailor on a multiday/week voyage). In that regard an alarm works better to get your full attention. Then you can look at repeaters which you'll be glancing at from time to time anyway. I only mentioned it as your early comment seemed disparaging against using an alarm.

Personally. I use my chart plotter with AIS and RADAR alarms for both (2 on the radar) alarms for wind shift, high wind (true), XTE, etc... I don't sail the boat them, but they do come in handy.

I also have a GPS inside recording track data, OpenCPN running on my pi attached to two screens I can choose which I want to use. And also either my tablet that can control my autopilot or MFD, and my computer.

I can look at any of these, but I still find alarms useful as a single handed sailor, just like many find anchor alarms useful.

It also helps from inside my boat have near 360 degree visibility, though have to crane a little for blind spots.

I suppose each unto their own.

[fxykty]

Originally Posted by Naughty Cat

Good tip about the reverse wrap. I'll start doing that.

Just like this

[Naughty Cat]

Textbook! I have started doing it. I would add for others that it doesn't make sense if doing a lot of trimming, but makes a lot of sense if leaving the winches for a period of time.

[Tsalta]

Yeh,

I have never seen the reverse wrap before. I have definitly added to our SOP.

So simple but what an enourmous potential increase in safety.

Cheers

[barnakiel]

Originally Posted by Tsalta

Yeh,

I have never seen the reverse wrap before. I have definitly added to our SOP.

So simple but what an enourmous potential increase in safety.

Cheers

New to sailing, eh?


Believe me or not, but it was me who invented the reverse wrap, when I was about 7. Some time later I discovered I was not the first inventor though!


;-)


Another funny story I learned the stopper hitch when I learned the basics, and never found any use for it in a dinghy. Then BAM we go sailing a keelboat - and I am using it as one of maybe 3 or 4 most often used knots/hitches.



b.

[Tsalta]

I'm new at everything, even if I've been at it for years.

Cheers

[Barra]

This topic is why I'm usually way more relaxed on night watches on monos than cats when it's gusty.

Its frustrating to reef for the gusts in unsettled weather as you end up plodding along undercanvassed 90% of the time until the weather settles sometimes days later.

I find I'm still watching the gear pretty closely even when reefed looking for signs of stress in the gusts. Not so concerned about a pitchpole or flip as gear breakage from sudden load increases which has happened.

Meanwhile on a well balanced mono you can just enjoy the heel as everything happens automatically as its designed to do. Often with a better average speed than the undercanvassed cat. Unless your trying to cook of course ;-)