Bestevaer 49ST

[estarzinger]

^^ I am not at all an expert on this . . . but my feeling on engines in the high latitudes . . . . we had the 75hp . . . . and I will say that I think the wave situation can be more about prop area than HP. We could have used a bigger prop (had 20" could have used 24 or 26" in some situations) but (IMHO) did not need more HP. Bigger props however obviously come with drawbacks (sailing drag and rope catching).

essentially we never found it smart to try to motor right into waves, and I think thats true unless you have a 'power boat', but we did find it extremely effective to motor/sail (just main up) at a 20 degree apparent angle - made excellent vmg and did not need more hp, just could have used more blade area for push thru the wave cycles.

In the end I was happy with the compromises we made in this area. We never could not get anywhere because of lack of HP or prop.

As an aside, Dock, the lower HP yanmar blocks are reputed to be more reliable than the higher spec ones. It's the same block, but the higher hp models drive it harder and have additional equipment hung on it (coolers and various spec turbos). I have never seen the actual data but it makes sense to me that a 'detuned' block would be more reliable. Listening to your desires and priorities, if you ever seriously consider another boat, I honestly think you should think about Dashew's "ultimate logical solution" - the offshore powerboat - there is obviously a ton of power generation (both electricity and propulsion) and they tend to have much better dinghy space. If you want a systems heavy, high power gen, motor thru anything, environment it just makes sense.

[Panope]

Originally Posted by estarzinger

^^ I am not at all an expert on this . . . but my feeling on engines in the high latitudes . . . . we had the 75hp . . . . and I will say that I think the wave situation can be more about prop area than HP. We could have used a bigger prop (had 20" could have used 24 or 26" in some situations)................

I'll second the recommendation for over-sizing propeller diameter/area.

Panope (15,000 lbs) went from 15 horsepower with a 14 inch diameter 2 blade prop to 40 horsepower with 18 inch diameter 3 blade. Even when running the new engine at 15 horsepower (matching the old engine's max power), the boat motors into wind a waves much much better than before. Naturally, the extra power is icing on the cake for bashing into stronger wind and chop.

-Panope is powered at 5.3 horsepower per ton. I am very happy with that and an 18" prop. (Panope is less than half the weight so may not be a good comparable).
-Hawk is powered at 5.0 horsepower per ton. Evans wished for (at times) a prop larger than his 20".
-Dockhead is powered at 4.5 horsepower per ton. He is unsatisfied (not sure of his prop size) and dreams of a HR64 with 300 horsepower or 8.3 horse power per ton!
-The Bestevaer 49 with 75 horsepower is 4.4 horsepower per ton.

Sounds like a 24", 3 blade feathering propeller would be just the ticket.

Steve

[Dockhead]

Originally Posted by Panope

I'll second the recommendation for over-sizing propeller diameter/area.

Panope (15,000 lbs) went from 15 horsepower with a 14 inch diameter 2 blade prop to 40 horsepower with 18 inch diameter 3 blade. Even when running the new engine at 15 horsepower (matching the old engine's max power), the boat motors into wind a waves much much better than before. Naturally, the extra power is icing on the cake for bashing into stronger wind and chop.

-Panope is powered at 5.3 horsepower per ton. I am very happy with that and an 18" prop. (Panope is less than half the weight so may not be a good comparable).
-Hawk is powered at 5.0 horsepower per ton. Evans wished for (at times) a prop larger than his 20".
-Dockhead is powered at 4.5 horsepower per ton. He is unsatisfied (not sure of his prop size) and dreams of a HR64 with 300 horsepower or 8.3 horse power per ton!
-The Bestevaer 49 with 75 horsepower is 4.4 horsepower per ton.

Sounds like a 24", 3 blade feathering propeller would be just the ticket.

Steve

On light ship displacement I have 5.0 horsepower per metric ton; 5.5 per English ton. This is absolutely plenty 99% of the time, all the more with a variable pitch prop (Autoprop) which pitches down when load is high, giving more "leverage" and using available power more efficiently. Out of 3800 RPM rev range, usual cruising speed is only 1800, less often 2000, and 2500 is usually enough when a moderate amount of power is needed.

So judging by my case, 5.0 hp per ton light ship is really plenty for most people.

But "most people" don't spend a lot of time powering against hard weather. The demand for power in that case goes up exponentially, and it could even be a matter of life and death. Of course, far more power is available from the sails, than from the engine, so Plan "A" will always be to sail against hard weather, or motor sail (something I did a lot of last year struggling upwind for 1500 miles with old sails), but there are cases (no room to tack; harbor entrance; rig problem; etc.) where only power will do.

Concerning prop size: Great care should be taken not to overprop the boat. This destroys engines.

If I were building a boat like this, I would look for a Hundested manually variable pitch prop, or at worst, a Brunton Autoprop. Variable pitch is pure gold for motor sailing or hard weather. Hundested is the dog's danglies for this and the perfect prop for an expedition-type boat, but has a couple of drawbacks: (a) from 150 horsepower; they don't make small ones; (b) requires an extra control cable, mechanism, lever at the helm; (c) cost.

From the Hundested site:

The Advantages of Controllable Pitch Propellers

A fixed propeller, designed for maximum speed, cannot give maximum power at low speed, while a fixed propeller designed for power, cannot achieve maximum speed.

With a controllable pitch propeller it is always possible to obtain full utilization of the engine, irrespective of the purpose of the vessel.

Maximum horsepower can be taken from the engine – without overloading – by changing the pitch.

Even if the engine drives a winch or a shaft generator, the number of revolutions can be kept constant – and the speed of the vessel can then be regulated by means of the propeller pitch.

At speeds lower than the maximum speed the engine’s fuel consumption can be reduced considerably by increasing the pitch and lowering the number of revolutions while maintaining the required speed. In this way the loading of the engine and the total efficiency of the unit is increased.

When using sail and engine power at the same time the correct pitch can always be obtained so that wind and engine together are utilized in the best possible way.

Prompt and inexpensive replacement of individual blades in case of damage to the propeller.

Engine idle speed on a fixed pitch propeller vessel often propels the vessel too fast for docking manoeuvres whereas a CP propeller offers superior low speed vessel control.


From my own experience: From more than 20 years of using Brunton Autoprops on two different boats, I would never ever go back to a fixed pitched prop on a sailing vessel. It is a revolutionary change. Imagine a car with only one gear. That's a normal prop. It's almost always in the wrong gear. Compared to a car with many gears -- that's a variable pitch prop.

[weavis]

In my experience with Motor boats.

I overpropped conservatively. There reaches a point when the gains are no longer effective.

75hp with strong wind over tide would be a test for your boat. I have been stood still in a 17 foot motorboat and a modern 40hp on full revs.

[weavis]

I am pro Solar in a big way. I also like wind generators.

The cons.

Effectively, charging from solar can only be counted in sunlight hours. So in the UK, thats about 1 hour a day All power consumption requirements have to be divided IN REALITY by sunlight hours. Any extra usage ie bilge pumps start running, emergency maintenance with tools, extra guests on board, will seriously hurt the power reserve. A single battery failure will hurt the reserve, a multiple one is disaster.

A purpose built boat is a home. I see no reason on earth to deny oneself extra power for safety and necessity ever. Dont have to use it often but it is there. If you ever have a party and need to heat 30 gallons of water for the crawdad boil or the crabs......... plug it in, and let the water maker keep filling the tanks. Gas cooker took a dump? miles off shore? Plug in the electric plate and keep going. Solid fuel heater misbehaving? Plug in the fan blower and keep going. Need to do work on the boat and the obscure rip off marina wants to charge you expensive for electric? you got the picture.

My wind generator....... lovely thing. Only ever used it offshore as the noise was unbelievable.

LOL. a while back, guy next to me broke his shore power cable...... I just wired straight into my 2k genny and he was able to finish his task whist wife went off to get a new plug.

I have gas cooker and heating, I like them. I also has 3 large tanks, now forced by space to only carry 2. Cost of gas is now 33 sterling for 15kg.
It hurts.

I have made a note that if ever I build a boat, it will have solar and a generator. Living in England makes you look hard at realities when the sun dont shine.

[Dockhead]

Originally Posted by weavis

I am pro Solar in a big way. I also like wind generators.

The cons.

Effectively, charging from solar can only be counted in sunlight hours. So in the UK, thats about 1 hour a day All power consumption requirements have to be divided IN REALITY by sunlight hours. Any extra usage ie bilge pumps start running, emergency maintenance with tools, extra guests on board, will seriously hurt the power reserve. A single battery failure will hurt the reserve, a multiple one is disaster.

A purpose built boat is a home. I see no reason on earth to deny oneself extra power for safety and necessity ever. Dont have to use it often but it is there. If you ever have a party and need to heat 30 gallons of water for the crawdad boil or the crabs......... plug it in, and let the water maker keep filling the tanks. Gas cooker took a dump? miles off shore? Plug in the electric plate and keep going. Solid fuel heater misbehaving? Plug in the fan blower and keep going. Need to do work on the boat and the obscure rip off marina wants to charge you expensive for electric? you got the picture.

My wind generator....... lovely thing. Only ever used it offshore as the noise was unbelievable.

LOL. a while back, guy next to me broke his shore power cable...... I just wired straight into my 2k genny and he was able to finish his task whist wife went off to get a new plug.

I have gas cooker and heating, I like them. I also has 3 large tanks, now forced by space to only carry 2. Cost of gas is now 33 sterling for 15kg.
It hurts.

I have made a note that if ever I build a boat, it will have solar and a generator. Living in England makes you look hard at realities when the sun dont shine.

To be fair to SWL's and Noelex's power scheme, they already have a considerable diesel-powered generator in their jumbo school bus alternator on the main engine. So they will not be completely dependent on solar.

If solar mostly covers your needs, then this is a perfectly good backup.

From a systems point of view, this is not worse than what I have now, which is genset backed up by school bus alternator, and probably better since there is nothing to go wrong with solar. The downside is that you have to limit your power consumption. That prevents you from doing things with electrical power which require abundant power, and which eliminate other fuel sources, etc. --

Electric cooking
Electric heating
Aircon
Heating water

etc.

I'm actually not quite sure how their washing machine is going to work on solar -- requires a lot of power even without electric drying.

Solar is fabulous -- who could not be a fan of it. But like everything it has certain limitations and drawbacks.

[weavis]

Originally Posted by Dockhead

To be fair to SWL's and Noelex's power scheme, they already have a considerable diesel-powered generator in their jumbo school bus alternator on the main engine. So they will not be completely dependent on solar.

If solar mostly covers your needs, then this is a perfectly good backup.

From a systems point of view, this is not worse than what I have now, which is genset backed up by school bus alternator, and probably better since there is nothing to go wrong with solar. The downside is that you have to limit your power consumption. That prevents you from doing things with electrical power which require abundant power, and which eliminate other fuel sources, etc. --

Electric cooking
Electric heating
Aircon
Heating water

etc.

I'm actually not quite sure how their washing machine is going to work on solar -- requires a lot of power even without electric drying.

Solar is fabulous -- who could not be a fan of it. But like everything it has certain limitations and drawbacks.

I didnt go there regarding the washing machine or drying

However, if the primary reason for an arch is to put solar panels on to prevent shadow, Im not sure it will work as well as expected. Sail shadow screws with everything depending on position of sun and heading.Positioning of panels is entirely dependent on available space-and therefore to some extent, is a pain. Be nice to know the area of the coach house roof available for solar panels, but this will be negated if a cover is to be used for a shade........ it also means turning the boat around if the shadow hits the arch..... but then my panels are a little old so perhaps the newer ones are not so dependent on direct light.

I still think the main area of concern is the lack of another hull.

[Seaworthy Lass]

Originally Posted by Dockhead

To be fair to SWL's and Noelex's power scheme, they already have a considerable diesel-powered generator in their jumbo school bus alternator on the main engine. So they will not be completely dependent on solar.

If solar mostly covers your needs, then this is a perfectly good backup.

From a systems point of view, this is not worse than what I have now, which is genset backed up by school bus alternator, and probably better since there is nothing to go wrong with solar. The downside is that you have to limit your power consumption. That prevents you from doing things with electrical power which require abundant power, and which eliminate other fuel sources, etc. --

Electric cooking
Electric heating
Aircon
Heating water

etc.

I'm actually not quite sure how their washing machine is going to work on solar -- requires a lot of power even without electric drying.

Solar is fabulous -- who could not be a fan of it. But like everything it has certain limitations and drawbacks.

One thing I should explain is that at the moment we have an inbuilt diesel DC generator and it is simply not required. It is just run a minimum time purely to keep it healthy.

Dockhead you are very correct - we will have back up on the new boat via the engine alternator. Also, if problems occur with the super reliable solar system, Noelex has the skills to repair or jury rig the system.

Until recently solar power was used on boats as a supplement rather than a primary source of power. With the availability of large cheap solar panels, this has changed. Our current solar system provides 99% of our electricity. We dislike motoring and do very few engine hours (our engine was replaced 6 years ago and with using the boat well over 300 days a year during this time, the new engine has only accumulated only just over 400 hours).

Having lived on this solar power for so long very happliy, we are confident that a new system of over double the wattage will more than fulfil all our needs (washing machine using a cold wash included).

We truly don't want to be relying on a generator or engine for our primary source of power for vital functions of watermaker, cooking, heating.

Dockhead, your power needs are very different to ours. A generator suits them well (and as one is being used, it is then appropriate to convert all sorts of systems to run off this). It is simply unnecessary for our needs. It is not a case of one system being universally superior. Solar suits us perfectly.

SWL

[Panope]

Originally Posted by Dockhead

.........Concerning prop size: Great care should be taken not to overprop the boat. This destroys engines.

If I were building a boat like this, I would look for a Hundested manually variable pitch prop, or at worst, a Brunton Autoprop. Variable pitch is pure gold for motor sailing or hard weather..........

Dockhead, Just to clarify, I was advocating larger diameter/area, not over-propping. Large gear reduction ratio is the key. Variable pitch is a nice feature but when it comes to maximizing low speed (boat speed) thrust, nothing beats a larger, slow turning propeller.

Consider the tug boats of 100 years ago. Many had less than 100 horse power yet they were able to create tremendous, ship pulling force because they had absolutely humongous, slow turning propellers. Many folks will quickly say that these old "house sized" engines somehow made "bigger horsepower" because of some sort magic in their high torque rating. The truth is that a modern, high revving engine will turn that giant old tugboat propeller just as well given a large enough gear reduction box - A.K.A - torque multiplier.

The standard for sailboat propeller sizing was set back when engines were tiny and only expected to be used for docking or windless conditions. Consequently, sailing performance dictated the undersized (diameter) props that most sailboats have. Now that folding/feathering props are common, the need for these small propellers as been reduced greatly.

I propose that for your need to occasionally bash into F7 or greater, that a larger slower turning fixed pitch propeller will give you far better performance than your smaller, controllable pitch prop . Naturally, a combination of both would be Ideal. Do you happen to know your propeller diameter and gear reduction ratio?

It may be that Noelex and SWL's cruising style is not the motor-bash type and will never need this kind of thrust that you and I find so important.

Steve