Colvic Watson 32, Rehabilitating the Traditional Motorsailer
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- čas přidán 24. 01. 2024
- This video shows how we turned our traditional motorsailer into a sailing boat, by cleaning up her underwater shape and increasing her sail area. First half, how it's done, second half, how she goes. Enjoy!
Excelleent video of the vast makeover. She seems to be a capable vessel, indeed. And she looks good in real life. Not just on TV. 😀
Great work. She's certainly picking up her skirt and running now. Quite the transformation and an attractive design to boot. 😎
The second time I have watched your video very informative thank you
Wonderful video Andrew, very enlightening.
The pace and narrative were perfect! Good luck in the future with your new born CW.
Chapeau!
I still have the original article in a folder. She certainly trucks along! A friend went through the same process with an old Tahiti ketch, and although not as stiff, she was certainly under canvassed.
Very good. I will buy a MS.
Thank you for this vid especially the rudder, deadwood mods must do them to mine.
Hi Andrew, very good video about all the improvements that you have achieved. A fine ship is your Big Ann, beautiful and comfortable. And so many ideas about poorly performing oldfashioned sailboats and motorsailors destroyed in less than half an hour.
How much does it cost to sail around the world?...everything most sailors got, and more. Mental, emotional. Finances relationships. Family. Educational. And so much more, all in decisions. Knowing how to Care for
others in a great stress. Adventure un matched...bendiciones...m
Excellent video! I do have a similar boat under refurbishment and have wondered about increasing sail area. But that is for later. First fiks boat.... Thanks for sharing! 🙂
Thank you. Before making any increases to your sail area, make sure your boat has the stability to carry it. I recently had a chat with a gentleman who owns a Fisher 30, which has the same hull as your version. He told me that he had enlarged and streamlined his rudder as well and was very happy about the improvements it had brought to her steering, including the ability to steer in reverse. Best. A.
@rFlow896 I think the stability should be sufficient to increase a bit yes. S.A./Displ is only 8.89 and Displ/len is 436, with Capsize Screening formula at 1.7. Slightly sea-heavier then your Colvic Watson. So comparable I think. I did actually service the rudder two years ago as I found a critical fault inside the rudder (covered in this video: czcams.com/video/Kl-J6uUPCuw/video.html). Extended the rudder ever so slightly and glassed all in. It has sort of a wing-shape. Since this is a project boat I have yet to sail it and feel the rudder work.
@@hsobstadI am not suggesting that it cannot be done, but I am advising caution. The two main factors for initial stability, which equates to sail carrying power, are beam and a hard turn of the bilge. Beam enters into the equation to the third power, hence: even a small increase in beam increases stability considerably. Compared to the Fisher the CW has much more beam and a harder bilge. The Fisher has a slacker bilge and greater immersed volume deep down. I think this might make her a seakindlier boat than the CW. However, as with all things, there is a tradeoff. I remember seeing a Dutch Fisher, a 34, I think, which had been given a (much) taller mast - it seemed to sail at rather pronounced angles of heel. That said, Fisher did over the years increase SA on the 34s and 37s and even the more recent reincarnation of the 25 was given more sail.
@@LaminarFlow896You may know but the Fisher 30 and the Fisher 30 Northeaster has very different beam with 2.82 vs 3.15. Your boat is about 20 cm wider than mine. I understand what you write, that is is an important factor. Then we have the Fisher 31 that has the same beam of 3.15 as my Northeaster. As I understand that boat is built on the same hull, but extended in the bow. The Fisher 31 has a much larger sail area.
Anyway, I will follow your advice and be careful. 🙂
Hi Andrew, A year ago my friend who owns a Nauticat 33 MkII like mine, passed to me your PBO article. I did the rudder modification but with a 0020 profile to match the thickness of the deadwood, hoping to get away without the deadwood profiling. The thicker rudder was also an idea of a Dutch owner of the same type of boat, who obtained good results.
I found that now I have better control at low speed under engine, and can turn in marinas accurately with engine in idle. In reverse, the improvement is there, but marginal.
Under sail, the strong weather helm is still very much there. This occurs even far from being on a close reach, and with little heeling. Hence, I have decided to also work on the deadwood as you suggest (and perhaps adding the wedge to the rudder). After having seen your photos in the video, I have to ask: is it OK to use ferro cement on a fibreglass hull?
However, in my case, I think propeller drag is another major culprit for weather helm. I have noticed that if, while sailing with engine on but in idle, I then stop the engine, I lose at least 1kn of speed. In both conditions, the propeller is spinning, but in the latter at a reduced speed, hence producing more drag. Obviously, the transmission is playing a part in preventing the propeller to spin faster and reduce drag. Overall, it seems to me that in my case reducing propeller drag with a feathering or folding propeller, if clearances allows, might lead to a sensible gain in speed and perhaps weather helm worth the investment.
Thank you for your article and video. It has been a source of knowledge and inspiration. I also appreciate the references in your article. I have just received 'Sail Performance', and ordered 'The Nature of Boats' and 'Principles of Yacht Design': a vast source of accessible insights.
Thank you for your kind words.
I only used the ferro in the steel rudder shoe - Steel and concrete are a happy marriage. Seven years later it is still in perfect condition.
The profiling has no effect on steerage in reverse, increasing the rudder size does. I recently spoke to a gentleman who increased the size of the rudder on his Fisher and was able to confirm the result.
I strongly believe that both fairing the deadwood and profiling the rudder is the key to improved performance and reducing weatherhelm.
A common result of changing to a feathering/folding prop is a reduction in weatherhelm. The reduction in turbulence allows the rudder to function much better and contribute more effectively to lateral plane. Streamlining the deadwood, in our case this was between 5" and 7" wide, has the same effect.
Best of Luck with your modifications, A.
Well done, Andrew. Loved your video.
Appreciative of the wry sense of humor with which you've put several myths to rest, I'm wondering what one would do with her two masts if taken under power through rivers & canals. Their hinged sloop masts are a primary reason I follow Colvic boats, in general. I'm presuming one would pull BA's w/crane & stow them at the same marina to await a return trip?
Hi there, interestingly, our boat has been through the French canals, from the Med to the North, though not under our ownership. The masts were simply stored on deck. I have, myself, been through the Canals as well, on a larger vessel, and we did the same. There are craning facilities at all entry points and it is a common procedure. There is also an option to have your mast(s) shipped ahead by road to your destination. Storage, while waiting for return, is of course also an option. Our mizzen is light enough to be stepped by hand from the wheelhouse roof and I have done this several times by myself. I do not think that a mast in tackle is essential.
@@LaminarFlow896 Glad to hear it's not uncommon as that's what I hope to do one day too - currently in the saving up for it zone. Fair winds to you for the encouraging reply.
Great video Andrew. You mentioned the increased mast and boom sizes, which have now improved the sailing performance by quiet a bit. I was just wondering if you could pass on what the sizes of masts, etc are? now.
The original mast supplier stated in a letter to the builder that, in his opinion, the CW 32 was "grossly underrigged" I concur with this. Consequently, the main mast was lengthened by 6' from 30' to 36' (9.3m to 11m). The mizzen was kept the same at 24.5' (7.5m), main boom length was increased from 3m to 3.8m and the mizzen boom from 1.85m to 3m. This increased the SA by about a 1/3 over the original design, giving a SA/D of about 13, which is still near the bottom end for a motorsailer according to Ted Brewer. According to my calculations, and by which I followed several methodologies, the original design is not balanced. Indeed, though still not perfect, our modified rig came out the better.
Hope this helps, A.
Hi Andrew, do you still have the original sails and if so would you consider selling? I have recently purchased a ketch rigged Colvic Watson but unfortunately her sails had been lost.
Hi James, unfortunately my CW was never standard rigged. When we bought her she already had a higher main mast and booms and I rather doubt the sails would fit a standard 32. When we replaced the sails they were some forty-odd years old , no longer very pretty, to say the least and our last voyage to the Baltic had pretty much given them the coup de grace. Sorry not to be of more help. A
Excellent.
Great video Andrew and very interesting. Be interesting to see what she would do with a feathering prop as well. Have one on our new boat and have been impressed in our first season.
Quite fancy moving to a more traditional motor sailor when i retire in 5-7 years but the thought of poor performance has really put me off. Doing these sort of upgrades to something like a fisher 37 could be transformational for me in the future
Thank you. I have given the idea of a feathering prop some thought. However the effect is much more pronounced on a lighter vessel, as prop resistance represents a greater part of overall resistance. We can and do let our prop spin, which reduces resistance by some 40%. I have calculated the increase in projected speed for our boat to be in the neighbourhood of 0.2 kts. For such a marginal increase I'm not sure I could justify the additional expense. I have considered drying out the boat to remove the prop for an afternoon ... Best, A.
Your bowsprit looks great, but what I can't see is how it folds up, and locks in the down position. If I am right about this it hinges at a point about level with the bow of the boat, and as it pivots upwards the bobstay becomes slack. If that is correct, how is it pulled down and locked in position?
Yes, you are correct, it hinges at the bow and upwards. To do this, you pull the pin on the bobstay and unhook the furler. One of the two mating faces has a stud and the other a hole. This prevents the faces from slipping against each other and keeps the tubes in column when under compression. The short strut is designed to absorb the anchor load.
Thank You. It looks brilliant. Sadly, I sold my yacht after a few health scares, but had been planning a bowsprit in the hopes of putting a light airs sail onto a furler as the cruising chute was difficult to deploy single handed. @@LaminarFlow896
Well maybe look one time to my " enhecements" nauticat i agree with most off your claims...but more sail area= more stab.= more keelweight !!??= stronger rigging!!!???the given speedspecs ...are if there are really treu...mindblowing,we have to discuss a lot!!!!! Naca 016 is my new shape,+ 400 kg of lead under the keel,taller masts etc ... also the “tail” on the end enhances indeed the effectiveness off the rudder with low speeds,used by slow heavy boats to manoeuvre better with sliw speed,but here??its an drag with speeds yoy mentioned cruising!?
9 knots treu the water ,with an waterline off under 10 m…. Take that patent!
Thank you for your interest. I did not increase the vessel's stability. What stability there is, is inherent to the design. Nor did I have to add any ballast. The factors that govern "stiffness" or ability to stand up to her rig are a fairly wide beam and a comparatively hard bilge. Not all motorsailers have this. Ballast, at the relevant angles of heel, that is up to 30 degr., plays a relative minor roll as to what is considered stiffness and sail carrying power. To wit, contemporary, wide beam designs manage with ballst ratios well below 30%. As to her speed: The CW 32 has a relatively high prismatic coefficient of 0.61. This provides considerable buoyancy to her ends which allow her, combined with a clean, flat run, to reach speeds in excess of a "traditional" hull speed. The price for this is a less than stellar windward performance, due to a blunter bow. as well as a slight penalty at lower speeds. As to the performance of the pressure wedge, I refer to the work done by Nguyen. & Ikeda. True, there is a slight penalty in drag, but the feature provides 17% more lift, which seemed a fair tradeoff considering the original rudder is really too small. Either way, the results speak for themselves. The videos are true and not doctored in any way. They speak for themselves.
@@LaminarFlow896thanks,i still dont understand how you managed her stability,wigh double the sailarea as original,also rigging attachments are surely not calculated for those new big forces,windgust will put lots off power on these,since the boat is heavy and not rezpond quick....
What do you mean by hardbilge??
@@guidouytterhaegen Hi Guido,
The factor that governs rig loads is the boat's righting moment or RM. If anything, increasing mast height and sail area reduces RM by raising the centre of gravity. The only point to keep in mind, is the increased compression loads due to narrower shroud angles, but that is likely compensated for by a reduction in RM. Taller masts will have a stronger section, unless you have multible spreaders, to compensate for the longer, unsupported panel lengths. More sail area does not increase the loads on the rig - it just means the boat heels more and sooner. What does increase rigging loads, is overloading a boat, which increases initial stability and RM at low angles of heel. A completely circular underwater section would be a "soft bilge" and have virtually no form stability on its own. A more rectangular or U-section, when pronounced, would be called a "hard bilge". As the centre of buoyancy moves out to the immersed side when heeled, this creates a powerful righting moment, especially on a heavy boat. Here: GZ, (the distance from the centre of gravity to the centre of flotation,) times the weight of the boat gives you the righting moment. GZ x G = RM.
@@LaminarFlow896 make sense,could you say what the benefit in speed would be with or without the kutterstaysail,and did you have to ad rxtra backstayrigging to support the extra forces on the mast?
So ghe hard bilge as i understand is the fact as i also noticed on the foto when your baot was on the dry,that after an sharp curve on top of the keel the hull goes nearly flat to the sides ,then again a sharp curve upwards ?
@@guidouytterhaegen Hi Guido,
From a broad reach to close hauled the stays'l adds an extra 0.5 - 1.0 Kt. Yes, I added backstays to take the loads. However, In think running back stays are better, as they reduce the compression loads, but it hasn't been a problem so far. Crossing the North Sea recently we did 6.5 kts under main, mizzen and stays'l during a 30 kt squall (broad reach)- no issues.
Correct, the hard bilge part is described by the sharp turn at the outboard end of the bilge flat.