Sailing Colvic 28 without using motor

rotrax

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The LM's are really a yacht with a hard doghouse. I have a similar vessel in NZ, a Hartley 32. Not really a Motorsailer in the same vein as the ones under discussion, those with a Pilothouse.

LM's do sail well, you are right there.
 

Laminar Flow

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The LM's are really a yacht with a hard doghouse. I have a similar vessel in NZ, a Hartley 32. Not really a Motorsailer in the same vein as the ones under discussion, those with a Pilothouse.

LM's do sail well, you are right there.
Well, I'm not sure I would call their inside steering a wheelhouse in the sense that the Watsons, Fishers or the SP cruiser have one.
One of the best "modern" MS is perhaps the Elvstroem 38, though it does use flexible panels to close off the helm and if you can overlook the affectation of it's bulbous bow.
 

Arcady

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And one of those might be?

LaminarIf there is one, please let us know what it is..................................
Well since you ask, I would volunteer the Mark Ellis designed Cabo Rico built NorthEast 400. Undoubtedly a motorsailer in style, but a fine sailboat too.
 

Laminar Flow

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One could also add the Moody's to the list, though I'm sure the owners may squirm at the thought.
To note, the current crop of super expensive "expedition" yachts also seem to prefer above ground living and I have not as yet seen anyone in a black robe point a shaking finger at them while hysterically screaming windage. There has been a lot of nonsense written about how super efficient a cruising yacht has to go to weather when most seem to motor, even those with skinny black masts and bendy rigs with dozens of spreaders.

I am constantly surprised how far such discussions are removed from the realities of cruising and that, at the end of the day, real life performances are close enough as to make little difference.

I did enjoy passing an AWB of a similar size to our tub in the Baltic while close reaching in a F5. I waved to him, casually leaning on the rail in our deep cockpit as we passed him close enough to weather for him to see my stupid grin. He didn't seem to be the most accomplished sailor, but he did start fiddling with his sails as we passed him, going near enough a knot quicker with our forty year-old rags. He never did catch up.
In truth, with a comparable SA/D ratio, there is very little difference to be had on most cruising relevant courses.

The next thing people usually come up with in the motorsailer discussion is the concept of the lee shore and in the day of square rigged ships that was indeed bad news. So, all square riggers on this forum, take care. The rest you, but especially the motorsailers, if you were reckless enough to get yourself embayed, just start that lump of metal in your bilge and motor to safety.
If your boat is not a sreecher to weather, you will never win a race. True, but the level of brain washing cruisers have be put to in this respect is astonishing and some comments I have read on this and other forums reflect that : if it is not made of carbon and mylar with a super short, deep fin, it will not go to weather at all and you will die on that famous lee shore, never mind a long keel or, God forbid, multimasted or even a gaff rig. Although I do not need to own and sail one, I always delight in pointing out that Colin Archer's life boats, afflicted with all the features that make windward work impossible, could quite well claw their way off a real lee shore and in conditions that would leave brown stains in most sailor's undies and do it while towing a string of five fishing boats. I wonder if they fretted much about VGM and tacking angle? Obviously when they did, they started installing engines and at that point they even added a wheelhouse.
 

Supertramp

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One could also add the Moody's to the list, though I'm sure the owners may squirm at the thought.
To note, the current crop of super expensive "expedition" yachts also seem to prefer above ground living and I have not as yet seen anyone in a black robe point a shaking finger at them while hysterically screaming windage. There has been a lot of nonsense written about how super efficient a cruising yacht has to go to weather when most seem to motor, even those with skinny black masts and bendy rigs with dozens of spreaders.

I am constantly surprised how far such discussions are removed from the realities of cruising and that, at the end of the day, real life performances are close enough as to make little difference.

I did enjoy passing an AWB of a similar size to our tub in the Baltic while close reaching in a F5. I waved to him, casually leaning on the rail in our deep cockpit as we passed him close enough to weather for him to see my stupid grin. He didn't seem to be the most accomplished sailor, but he did start fiddling with his sails as we passed him, going near enough a knot quicker with our forty year-old rags. He never did catch up.
In truth, with a comparable SA/D ratio, there is very little difference to be had on most cruising relevant courses.

The next thing people usually come up with in the motorsailer discussion is the concept of the lee shore and in the day of square rigged ships that was indeed bad news. So, all square riggers on this forum, take care. The rest you, but especially the motorsailers, if you were reckless enough to get yourself embayed, just start that lump of metal in your bilge and motor to safety.
If your boat is not a sreecher to weather, you will never win a race. True, but the level of brain washing cruisers have be put to in this respect is astonishing and some comments I have read on this and other forums reflect that : if it is not made of carbon and mylar with a super short, deep fin, it will not go to weather at all and you will die on that famous lee shore, never mind a long keel or, God forbid, multimasted or even a gaff rig. Although I do not need to own and sail one, I always delight in pointing out that Colin Archer's life boats, afflicted with all the features that make windward work impossible, could quite well claw their way off a real lee shore and in conditions that would leave brown stains in most sailor's undies and do it while towing a string of five fishing boats. I wonder if they fretted much about VGM and tacking angle? Obviously when they did, they started installing engines and at that point they even added a wheelhouse.
Well said.

You can sail a racer badly and you can sail a motorsailer or cruiser well. I like your modifications to the CW and I suspect you would get off that lee shore with or without them!

The boat design and its idiosyncrasies are part of it but its really how you build up experience in a range of situations and conditions that complements your boat choice. Then you can make adjustments and improvements to suit yourself. Which boat you start or end with doesn't really matter so long as you are comfortable with it.
 

Laminar Flow

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Well said.

You can sail a racer badly and you can sail a motorsailer or cruiser well. I like your modifications to the CW and I suspect you would get off that lee shore with or without them!

The boat design and its idiosyncrasies are part of it but its really how you build up experience in a range of situations and conditions that complements your boat choice. Then you can make adjustments and improvements to suit yourself. Which boat you start or end with doesn't really matter so long as you are comfortable with it.
Yes, of course she could go to weather before I made the changes, just not very quickly. And, hereon lies the crux for all who claim a motorsailer doesn't have to sail fast or, more ridiculously, was not designed to.

Lift is proportional to the square of the speed.

For going to weather a motorsailer has a number of inherent disadvantages:

1) They have a high prismatic coefficient, while this is excellent news for reaching and running, the blunter ends, however, increase resistance going to weather. My boat's PC is 0.6 (optimum relative speed is 1.2) which actually gives her 25% less resistance at hull speed compared to a boat with a more common PC of 0.54. Most boats are designed to do well to windward.

2) Many traditional motorsailers have a long shallow keel, Fishers, Watsons, Banjers etc. While this may increase directional stability, it also increases wetted area and induced drag. Compared to a fin keel this is not an efficient set-up.

3) Many traditional style MS are very heavy: Fisher 25 D/L 485, the 34 with 433, the 37 with 407. My boat, by comparison is a svelte 360. In this context you simply have to accept that you are operating in a closed system. You will still be able to exceed traditional hull speed, just not by much and of course you can kiss surfing or planing good bye.

4) Voluminous hulls and superstructures increase wind resistance.

What has been done in the past is to take a hull that has a number of hydrodynamic handicaps, or better idiosyncrasies, and then cripple it completely by not giving it enough (sail) power to reach it's potential. Add to this the inefficiency of multi masted toy rigs and you have the perfect performance lemon. The 70's hysteria about the danger and difficulty of handling large sails is no longer plausible and, in terms of the mini sails on some MS, ridiculous.

To overcome the disadvantages of heavy displacement, increased wetted area, higher induced drag and a blunt nose a MS needs more sail and not less.

Since increasing the speed of our CW, first by fairing the rudder & deadwood and then by increasing SA, we have bettered her wind ward ability by at least 15 degr. The rudder is now an effective contributor to lateral plane, the higher speed increases lift significantly and both help reduce lee way. The added resistance of of wetted area is more pronounced in lght weather and can actually be fairly easily overcome by adding a bit more sail. Once in the swing of it, her momentum helps her push trough the waves.

Some brands recognized this. The Fishers added more sail to the 34's and 37's, the Banjer started out with 28 sqm, the last model had a 100 sqm.
Colvic, more focused on selling hulls for home completion, never made such changes to the design. Whether this was due to lack of feedback, I do not know, otherwise the steering problems could have been addressed long ago. It is now up to their owners to make the changes, which is appropriate for what was a mostly home finished boat, but this is not helped by self appointed experts who liked to claim there are no problems or that you will drown if you tamper with the design.
 

Laminar Flow

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What do you mean by a “cruising relative course”? Downwind?
Well, I actually said "relevant" not relative. In the context of cruising this pertains to the fact that cruisers tend to avoid long windward trecks. That said, we can and do sail upwind, but on long passages I'm happy to wait for a decent slant. Close hauled is fine, I just rather not spend days tacking to get there. I have my wife's full permission to say that as we still happily sail two up.

Example: Dieppe to Newhaven in one tack. Wind 12kts apparent, 8kts true, 4.8kts TTW. No need to motor or tack.

DSC_0943 (2) small.jpg
 
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rotrax

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Exactly. Our unmodified Island Packet SP Cruiser is hard work under sail alone to windward, the shallow draught - 1 metre - allowing significant leeway. We have been known to get to Falmouth via Cherbourg or Alderney so as to get a better slant on the wind.

I must get LF to look at our deadwood /rudder layout. There is a huge gap between the deadwood and rudder - improvement here might be benificial, as LF has found with Big Ann.

We are really looking forward to trying out our new furling reacher - it might be a game changer for us! Almost doubled our SA.

In perfect conditions - 15-20 kts true - we have reached hull speed, exceeded it through the water with a bit of tide.

Unfortunatly, those days are too rare.
 

Laminar Flow

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Hi Rotrax,
I looked up your keel/rudder configuration online and I have to say, as far as one could tell and compared to what ours was, it is exemplary. Unless your boat suffers from extreme weather helm, filling in the space between rudder and keel will not accomplish much other than adding to wetted area.

To make it a bit clearer to where a Watson owner gets to start out, I added the following pic. It shows the actual width of the deadwood and the result is a wedge of turbulence that severely impacts the performance of what is an already poorly shaped rudder. Apart from some pics of cobbled together fishing craft in developing countries, it was the worst example of hydrodynamic abuse I've ever seen. Under power the prop wash helps generate turning force and stabilizes the flow somewhat as far as steering is concerned, but under sail this is of course not the case and the prop simply adds to the turbulence. Overall, the coarse deadwood negatively affects both performance under power and sail. Conversely, it also the illustrates the opportunity for easy and significant improvement.

small deadw.jpg


In regards to your boat: The rudder and deadwood already look pretty good and simply being able to sail quicker with your increased sail area should improve windward ability.

Beyond this it would depend on how bad you've got the bug and how much effort you want to invest. There are essentially two options: a) Increase depth of keel or b) add an end plate to the bottom of the keel in the form of a Scheel keel, for example, and which could be fairly easily done and is an effective approach in shallow draft boats.

For now I think you should wait and see how your most recent improvements work out before taking further steps.

In a system where you have several factors contributing to performance, it makes the most sense when seeking to improve overall efficiency to address the weakest part first. If we are to roughly split a sailing boat into it's separate performance determining factors that would be the hull and rig (we'll ignore any contributions of a skilled crew for now).

A modern rig, well set up, is already pretty efficient and it is quite difficult to make significant improvements to it's windward ability. That leaves us with the hull/keel/rudder configuration. In regards to the underwater profile it has been found that even subtle changes can make for significant improvement.
Just recently we had a thread on the Sutton Hoo ship, where it was found that a very slight increase in the depth of the salient keel, from 2cm in former craft, to 4cm in the Sutton Hoo model, improved windward ability by 80%. I actually found that staggering.
Similarly, and more of a concern for us, there was a research series conducted at the Southhampton University on behalf of Laurent Giles Ltd. It demonstrated that quite subtle changes made over a series of models to the underwater profile had a significant effect on improving efficiency. I mention this case specifically as the original profile shows great similarity to your boats underwater profile. The case study can be found in Marchaj's "Sail performance", page 129.

Best, LF
 
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