Gludy
Well-Known Member
Raggies, in really bad weather heave-to and in effect stop and drift down ind at an angel leaving the disturbed water behind them that prevents waves breaking over them ...... can power boats do the same?
Heaving-To in a Powerboat
- Thread starter Gludy
- Start date
rich
Well-Known Member
Why heave-to when you have the power to keep going?
Gludy
Well-Known Member
If you are caught in really heavy weather in a sail boat - the wind provides ample power to keep going but its often wise to in effect park your boat, avoid waves breaking over you and have a relatively peaceful time until the weather passes.
In a power boat, I can imagine situations where it may be best to do the same in say a f9. In fact many fishing boats in the Pacific do just that and use a para-drogue to help them as well. I think they hold themselves t about 40 degree to the wind using the drogue and the wind on their superstructure. So heaving to in a power boat can be useful. Its not a question of power, its a question of how beat to cope, if caught out, in very heavy seas.
In a power boat, I can imagine situations where it may be best to do the same in say a f9. In fact many fishing boats in the Pacific do just that and use a para-drogue to help them as well. I think they hold themselves t about 40 degree to the wind using the drogue and the wind on their superstructure. So heaving to in a power boat can be useful. Its not a question of power, its a question of how beat to cope, if caught out, in very heavy seas.
michael_w
Well-Known Member
I thought that fishing boats in heavy weather "dodged" ie: They hold station by motoring at minimum revs bows into the seas.
Gludy
Well-Known Member
Well some do and that is heaving to for a power boat.
With a sailing boat the drift downward at about 40 degrees leaves an upwind water shadow of disturbed water as a trail to the boat. This stops seas breaking over the boat.
I the pacific I know some fishing boats do the same using a drogue.
If you heave to with just minimum power head into the sea or use a drogue head oninto the sea the effect does not seem to be as good - the shadow is much narrower just the bean of your boat and hence you are likely to still have seas break over you.
I have just watched a Storm Tactics DVD taht was all about this with yachts and in passing mentioned the fishing boats, so I was trying to see of there is any experience out there with power boats.
On this DVD they safely heave to in 70 knot winds!!!
With a sailing boat the drift downward at about 40 degrees leaves an upwind water shadow of disturbed water as a trail to the boat. This stops seas breaking over the boat.
I the pacific I know some fishing boats do the same using a drogue.
If you heave to with just minimum power head into the sea or use a drogue head oninto the sea the effect does not seem to be as good - the shadow is much narrower just the bean of your boat and hence you are likely to still have seas break over you.
I have just watched a Storm Tactics DVD taht was all about this with yachts and in passing mentioned the fishing boats, so I was trying to see of there is any experience out there with power boats.
On this DVD they safely heave to in 70 knot winds!!!
BIG_PLANS
Well-Known Member
I have heaved to in a 12000 grt reefer ship, so no reason why power boats shouldnt.
Dyflin
Well-Known Member
Happens all the time in the offshore industry on the supply ships etc., have spents up to two weeks "hove to" or dodging as it's called. Auto pilot on and just enough power to keep the bow head to wind and counteracting wind and tidal effects (which can be up to 70/80% on the sticks depending on the wind and sea state). Stick the GPS to plotter mode and you'll see of you are crabbing to either side as well. It's easily done and makes motion very palatable considering te conditions.
Gludy
Well-Known Member
Thats fascinating .... so you are head on into the sea?
How long can you stay on autopilot? Is it for hours?
Do you ever use a drogue?
What force winds have you done this in?
How long can you stay on autopilot? Is it for hours?
Do you ever use a drogue?
What force winds have you done this in?
Nick_H
Well-Known Member
Interesting question, but the technique of heaving to or dodging is probably of little use to powerboats on the basis that they are not usually that far from land, and do not go out when the weather is already that bad, so if it suddenly turns when you're already out there, there will be a delay before the waves really pick up, so best to use that to find shelter.
Gludy
Well-Known Member
If you are cruising you can end up in fairly heavy weather and the best policy is as you say - head for cover. Yet you can find yourself with a safe haven a bit too far away and the need to make yourself as safe as possible in say an f9. So it is surely as well to learn how to cope with exceptional conditions rather than not know?
I know power boats that cross Biscay etc, so very often a power boat can be at least a few hours, if not many hours from a safe haven.
Other power boats such as Nordhavens cross Oceans, even though they may only be 40 odd feet long.
I know power boats that cross Biscay etc, so very often a power boat can be at least a few hours, if not many hours from a safe haven.
Other power boats such as Nordhavens cross Oceans, even though they may only be 40 odd feet long.
Salty John
Well-Known Member
I agree it is important to have a contingency plan for heavy weather. Having recently become a stink potter after a lifetime as a raggie I have tried to equate the three basic raggie tactics to those I'd now use in a power boat.
1. Running off before a storm towing warps or a drogue: Probably not an option with a power boat because they tend to be less stable downwind and with less reserve bouyancy in the stern. I certainly wouldn't do it with my Grand Banks.
2. Heaving-to: On a sail boat this is a voluntary and controlled tactic, bringing the boat to 40-50 degrees off the wind and usually forereaching very slowly. The slick to leeward helps to dissipate the energy of approaching waves. A boat that is hove-to is technically underway. The equivalent power boat tactic appears to be "dodging". The boat is underway and under command. It takes the seas dead on the bow, which I think is best for a power boat with minimal keel area to create any significant slick.
3. Lying a-hull: This basically means you have abandoned any hope of controlling the situation and leave the boat to fend for itself. The power boat equivalent would be a loss of power. A sail boat with a lot of underbody area to offset its windage will weathercock around a position about 45 degrees to the wind, actually quite safe. I doubt a power boat would do this and be more likely to go broadside-to. To prevent this
you would need to stream a sea anchor off the bow to keep the bow into the wind.
These are sweeping generalizations given the huge variety of boats out there, but seems a reasonable starting point. Any experienced heavy weather power boaters care to comment?
1. Running off before a storm towing warps or a drogue: Probably not an option with a power boat because they tend to be less stable downwind and with less reserve bouyancy in the stern. I certainly wouldn't do it with my Grand Banks.
2. Heaving-to: On a sail boat this is a voluntary and controlled tactic, bringing the boat to 40-50 degrees off the wind and usually forereaching very slowly. The slick to leeward helps to dissipate the energy of approaching waves. A boat that is hove-to is technically underway. The equivalent power boat tactic appears to be "dodging". The boat is underway and under command. It takes the seas dead on the bow, which I think is best for a power boat with minimal keel area to create any significant slick.
3. Lying a-hull: This basically means you have abandoned any hope of controlling the situation and leave the boat to fend for itself. The power boat equivalent would be a loss of power. A sail boat with a lot of underbody area to offset its windage will weathercock around a position about 45 degrees to the wind, actually quite safe. I doubt a power boat would do this and be more likely to go broadside-to. To prevent this
you would need to stream a sea anchor off the bow to keep the bow into the wind.
These are sweeping generalizations given the huge variety of boats out there, but seems a reasonable starting point. Any experienced heavy weather power boaters care to comment?
landaftaf
Well-Known Member
ships and power boats are designed to 'heave too' bow to weather, steaming into the weather at minimum speed. one can expect to be hit from the side every now and again as storm waves do not come in from a uniform direction.
boats can lie to a sea anchor as well
(could start to swing the lamp but dont want to make anyone vomit)
a study for (large) commercial vessels has been done to see if lying a hull is a safe alternative ........ apparently it is. however this does not change the accepted practice of steaming into the weather at minimum speed. /forums/images/graemlins/cool.gif
boats can lie to a sea anchor as well
(could start to swing the lamp but dont want to make anyone vomit)
a study for (large) commercial vessels has been done to see if lying a hull is a safe alternative ........ apparently it is. however this does not change the accepted practice of steaming into the weather at minimum speed. /forums/images/graemlins/cool.gif
Dyflin
Well-Known Member
[ QUOTE ]
Thats fascinating .... so you are head on into the sea?
How long can you stay on autopilot? Is it for hours?
Do you ever use a drogue?
What force winds have you done this in?
[/ QUOTE ]
Yeah, usually the wind is the defining factor and so the seas may be slightly on the shoulder but pretty much head to weather. She just gently rises up and down unless it's very hairy and she can't hold this course then it's time to steam slowly up and down or run for cover.
Personally I've been lucky and only had to do this in a maximum of force 10 winds in the Northern North Sea, but it depends on how steep the seas are because if the props are spending any time out of the water as she rides over a waves then you are going to loose thrust very quickly and she'll drop off the wind.
The kind of conditions are shown in these videos (download them instead of opening them as they take an eternity to connect but much faster and worthwhile to download)
Video 1
Video 2
Video 3
Video 4
Video 5
All posted on a Norwegian ships forum and taken from this ship
We can spend months in autopilot if necessary, much more efficient then steering by hand! Handling a drogue in these conditions would not be good seamanship, too much risk involved to have people working on deck, plus the forces involved...
Thats fascinating .... so you are head on into the sea?
How long can you stay on autopilot? Is it for hours?
Do you ever use a drogue?
What force winds have you done this in?
[/ QUOTE ]
Yeah, usually the wind is the defining factor and so the seas may be slightly on the shoulder but pretty much head to weather. She just gently rises up and down unless it's very hairy and she can't hold this course then it's time to steam slowly up and down or run for cover.
Personally I've been lucky and only had to do this in a maximum of force 10 winds in the Northern North Sea, but it depends on how steep the seas are because if the props are spending any time out of the water as she rides over a waves then you are going to loose thrust very quickly and she'll drop off the wind.
The kind of conditions are shown in these videos (download them instead of opening them as they take an eternity to connect but much faster and worthwhile to download)
Video 1
Video 2
Video 3
Video 4
Video 5
All posted on a Norwegian ships forum and taken from this ship
We can spend months in autopilot if necessary, much more efficient then steering by hand! Handling a drogue in these conditions would not be good seamanship, too much risk involved to have people working on deck, plus the forces involved...
TigaWave
Well-Known Member
From the yacht perspective, I've never found any way of stopping waves breaking over the boat when its hove to.
I've only really had to heave to for the sake of crew rest twice and waves still break over the boat and she was still getting knocked flat, 90 degrees a few times.
Our track was about 120 degress to wind at 2knots but heading was 40-50 degrees to wind. Breaking waves tend to hit the side of the boat and make her head up each time and roll. The decision to run is based mainly on the height and shape of waves. Steep breaking confused seas I heave to, big flatter waves not breaking we can run off but check speed with trailed warps.
Whether or not you can see the waves coming is also another consideration, as it's the unexpected waves that will cause the broach.
I've only really had to heave to for the sake of crew rest twice and waves still break over the boat and she was still getting knocked flat, 90 degrees a few times.
Our track was about 120 degress to wind at 2knots but heading was 40-50 degrees to wind. Breaking waves tend to hit the side of the boat and make her head up each time and roll. The decision to run is based mainly on the height and shape of waves. Steep breaking confused seas I heave to, big flatter waves not breaking we can run off but check speed with trailed warps.
Whether or not you can see the waves coming is also another consideration, as it's the unexpected waves that will cause the broach.
Gludy
Well-Known Member
I have never hove to but in watching the Storm Tactics DVD they avoided breaking waves by heaving to and using a sea anchor so that they always stayed in the shadow of the disturbed water they left.
I personally have never hove to and have no practical axperience of it whatsoever - I am trying to learn.
I personally have never hove to and have no practical axperience of it whatsoever - I am trying to learn.
Gludy
Well-Known Member
[ QUOTE ]
. Running off before a storm towing warps or a drogue: Probably not an option with a power boat because they tend to be less stable downwind and with less reserve bouyancy in the stern. I certainly wouldn't do it with my Grand Banks.
[/ QUOTE ]
Yet towing a sea anchor seems to be the suggested method in a following sea - stops the boat veering from side to side? I do not know the answer, just making the comment.
[ QUOTE ]
The boat is underway and under command. It takes the seas dead on the bow, which I think is best for a power boat with minimal keel area to create any significant slick.
[/ QUOTE ]
I have a fairly deep keel on my new boat and wonder how it would work with a sea anchor held at an angle just like the raggies do - some fishing boats do this in the Pacific.
I have never seen an article on power boat survival tactics in rough seas - I have some books and these suggest the drogue behind you in following seas.
. Running off before a storm towing warps or a drogue: Probably not an option with a power boat because they tend to be less stable downwind and with less reserve bouyancy in the stern. I certainly wouldn't do it with my Grand Banks.
[/ QUOTE ]
Yet towing a sea anchor seems to be the suggested method in a following sea - stops the boat veering from side to side? I do not know the answer, just making the comment.
[ QUOTE ]
The boat is underway and under command. It takes the seas dead on the bow, which I think is best for a power boat with minimal keel area to create any significant slick.
[/ QUOTE ]
I have a fairly deep keel on my new boat and wonder how it would work with a sea anchor held at an angle just like the raggies do - some fishing boats do this in the Pacific.
I have never seen an article on power boat survival tactics in rough seas - I have some books and these suggest the drogue behind you in following seas.
Nick_H
Well-Known Member
Planing boats go stern to if left to fend for themselves, because the bow is very light in comparison to the stern, and has less draught and therefore less friction.
Nick_H
Well-Known Member
I would guess the reason for towing a drogue behind you is to avoid broaching, and you would need to be making ground for it to have effect.
Gludy
Well-Known Member
yes thats right - you would still be making ground for it to work - you are not hove to.
Salty John
Well-Known Member
Yes, I'm sure that's right. Once the seas got big enough to break over the stern I would be getting her turned round, head to the seas. Being pooped by a big sea in a power boat with a flat transom, big aft cockpit and patio doors fills me with horror!