Heavy weather - engine on or off?

If you've got the right sails on the boat I don't see any benefit in using the engine, and plenty of risks.

A heavy weather jib and 3 reefs in the main should provide plenty of power to keep the boat going. On my boat I can't see the engine alone providing enough power to make steering easy

With storm jib, storm staysail and 3 reefs in main in F9 close hauled, we will be well heeled - with the side deck underwater, making about 3 knots through the water, but making 0 knots over ground towards a windward destination.

I have tried it.

In the same conditions with the engine on we will make about 1 knot through the water directly into the wind without any sails. If there is no current we are making progress.

You will find that in all boats there is a wind strength where you cannot make any progress against the wind regardless of your sail wardrobe/number of reefs etc. Also the sea state will be against you as well.

Much better to turn around and go somewhere else.
 
With storm jib, storm staysail and 3 reefs in main in F9 close hauled, we will be well heeled - with the side deck underwater, making about 3 knots through the water, but making 0 knots over ground towards a windward destination.

I have tried it.

In the same conditions with the engine on we will make about 1 knot through the water directly into the wind without any sails. If there is no current we are making progress.

You will find that in all boats there is a wind strength where you cannot make any progress against the wind regardless of your sail wardrobe/number of reefs etc. Also the sea state will be against you as well.

Much better to turn around and go somewhere else.
All boats are different, mine is very happy under heavy weather jib (not storm), and deep reef in the conditions described (at least at the lower end - I've done that a couple of times). She will sit with the lee rail just about touching the water and goes like a train, doing a good 6-7 knots provided the sea is not too steep. Under engine I imagine I would struggle to make 1-2 knts, and the motion would be a lot less comfortable.

In my view I don't go anywhere at that sort of VMG, so I would go somewhere else. I would not be comfortable in any circumstances where the safety of the boat depends on the engine - just too many things can go wrong.
 
All boats are different, mine is very happy under heavy weather jib (not storm), and deep reef in the conditions described (at least at the lower end - I've done that a couple of times). She will sit with the lee rail just about touching the water and goes like a train, doing a good 6-7 knots provided the sea is not too steep. Under engine I imagine I would struggle to make 1-2 knts, and the motion would be a lot less comfortable.

In my view I don't go anywhere at that sort of VMG, so I would go somewhere else. I would not be comfortable in any circumstances where the safety of the boat depends on the engine - just too many things can go wrong.

Ok. Make that the upper end of a F10. Then I bet you have no sail combination which will get you to windward then.
 
Ok. Make that the upper end of a F10. Then I bet you have no sail combination which will get you to windward then.
Absolutely - but I don't think my engine would either. My guess is that the wind on the hull, mast and rigging would tend to push the boat down wind faster than the engine could counter.

I might try something like "heaving to" under engine, having the engine at low revs and the autopilot on to keep the boat's head to - or just off - the wind - but not with any idea of getting anywhere.
 
Absolutely - but I don't think my engine would either. My guess is that the wind on the hull, mast and rigging would tend to push the boat down wind faster than the engine could counter.

I might try something like "heaving to" under engine, having the engine at low revs and the autopilot on to keep the boat's head to - or just off - the wind - but not with any idea of getting anywhere.

With my boat, mid F9 with nothing up (i.e. minimum windage), with the engine on full revs (90 hp) pointing just off the wind is not possible. Point dead into the wind is not possible either. The boat will go backwards and swing around pretty damm quick. I can hold her at about 60 degrees to the wind then and will be heeling a fair bit. The decks will be under water some of the time.

I can heave to under reduced sail in the same conditions. Over ground I will be going downwind very slowly - probably a lot less than 1 knot through the water - however this is very difficult to correctly measure as there has always been a significant current when I have been out in those conditions. The boat will point at about 35 degrees to the wind and will be very settled and relatively comfy. The effect of the slick to windward on the approaching wave crests needs to be seen to believe. (I don't have a clue about the physics behind this and before I ever saw it, I never believed it possible).

Going down wind under bare poles without engine I will be at about 6 knots, stable, easy to steer and in perfect control.

No idea about F10. Never seen one (previous owner said he had been heaved to in one for 48 hours).
 
With my boat, mid F9 with nothing up (i.e. minimum windage), with the engine on full revs (90 hp) pointing just off the wind is not possible. Point dead into the wind is not possible either. The boat will go backwards and swing around pretty damm quick. I can hold her at about 60 degrees to the wind then and will be heeling a fair bit. The decks will be under water some of the time.

I can heave to under reduced sail in the same conditions. Over ground I will be going downwind very slowly - probably a lot less than 1 knot through the water - however this is very difficult to correctly measure as there has always been a significant current when I have been out in those conditions. The boat will point at about 35 degrees to the wind and will be very settled and relatively comfy. The effect of the slick to windward on the approaching wave crests needs to be seen to believe. (I don't have a clue about the physics behind this and before I ever saw it, I never believed it possible).

Going down wind under bare poles without engine I will be at about 6 knots, stable, easy to steer and in perfect control.

No idea about F10. Never seen one (previous owner said he had been heaved to in one for 48 hours).
Just looked your boat up - what a beauty! but you probably have a bit more windage than most people. I'm surprised you would use a storm job in heavy weather rather than just a staysail - it looks as if you would move the centre of effort well forward.

My 20HP ceases to provide sensible forward propulsion long before your 90HP.
 
Just looked your boat up - what a beauty! but you probably have a bit more windage than most people. I'm surprised you would use a storm job in heavy weather rather than just a staysail - it looks as if you would move the centre of effort well forward.

My 20HP ceases to provide sensible forward propulsion long before your 90HP.

To keep the balance. Otherwise I end up with too much weather helm. (I have tried it).

Really nasty stuff I will have 2 reefs, storm jib and storm staysail.

Not sure what happens with 3 reefs in the main. May be then the jib comes down as well. Never been in a situation needing to try that.
 
Let’s say you found yourself in 30-35 knots of wind and 2-3 meters of waves with a lot of rolling and pitching of the boat. These are obviously heavy weather and not survival conditions, since you can still sail (at some direction, not necessarily towards your course) with heavily reefed sails. Having the engine on could always help since it could provide some better steering or some push eg when climbing up the waves. In fact some articles or books mention that in these conditions a good method is to keep the main up (reefed of course) and motor sail. However, any sort of dirt in the fuel tank with all the rolling and pitching could easily block a filter and stop the engine. So, question is would you have the engine on and risk it? And does a full tank reduce this risk?
This is really a not “academic” question because I believe these are conditions which we should always prepared to do so. And just to add, let’s assume that we sail in a clear distance from shore meaning we don’t need the engine on to avoid going aground.

In heavy conditions I think the state of the crew dictates the answer. If motor sailing steadies the boat, as it usually will, the crew will benefit, the journey to landfall may be shortened. Clearly, sailing at night in these conditions, in a seaway even a TSS, presses the skipper to act wisely and at least motor past the point of exposure to traffic.

But if the crew is loving it and the boat is maintaining steady progress, the case for motor sailing is much reduced.

The comments about crud in the tank ruining the fuel lines is not without point, but is not a reason to exhaust the crew or stagger on being driven way off course....

If you're using autopilot beware the condition of the batteries - running the engine benefits the security of the electrical reserves.

I have made a crossing of the N Sea in my Fulmar in a full gale, and went to motor sailing as night fell. When the seas really get up and the wind is forward of the beam you have no choice if you want to maintain your course!

PWG
 
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