Part 2: Two other major sorts of monohull boats are seen in today's marinas. The full displacement monohull does not have a clear derivative in modern power catamarans, which all utilize planing to one extent or another. The monohull sailboat contributed sailing rig and other traditional attributes to the far more recent development of sailing catamarans, but it's hull form was generally abandoned (with the possible exception of daggerboards). These sail catamarans then evolved into today's second type of power catamarans, retaining virtually none of the monohull sailboat hull features. Finally, to converting sailing catamarans to power catamarans. Why? Sailing catamarans have, by virtue of their sail rigs, virtually unlimited range. Modern sailing catamarans are commonly used for coastal cruising as well as routinely crossing oceans. By virtue of their high sailing speeds, limitless range and their unique maneuverability under power they are particularly well suited to do so. In coastal and local cruising, sailboats of all sorts use their engines -- and don't use their sails -- maybe 90 percent of the time. Sailing catamaran hulls are similarly as slender as my second sort of power catamaran, or even more so, and use the slender hull minimized bow wake approach to breaking out of the 'hull speed wave trap.' Note please that they lack the modern power catamaran's 'semi-displacement' planing features of flat bottomed aft sections and powerful enough engines to achieve significant hull lift. They operate in strictly displacement mode. The particularly small engines needed to only approach displacement hull speed are designed into the hull with oodles of compromises and trade-offs which have evolved over a considerable time to uniquely suit the hull and engine combo. Adding a larger engine will be very challenging in terms of the strength of various hull components, size and shape of the spaces available, etc., and without planing capabilities in the hull shape, will not give spectacular improvements in top speed. Interior space utilization in sailing catamarans has evolved into very efficient and effective designs. Significant modifications to add larger engines or much larger fuel tankage will force some very unhappy compromises. Primary among these are considerations of weight and balance. Catamaran performance, both sail and power, is incredibly sensitive to both total weight, and to the presence of significant weight far from the center. Orders of magnitude more sensitive than the common monohull. Adding significant weight in upgraded engines, and far worse in increased fuel tankage to an existing evolved sail catamaran hull will cost large penalties in sail performance and boat motion, for small gain in top speed under power and/or greater range under power alone. The main fuel tank in my PDQ is probably the heaviest item aboard, and occupies the bridgedeck space where the center of gravity of the whole boat resides. Adding a large fuel tank to a sailing catamaran would severely compromise its behavior if it could not be correspondingly placed. Sailing catamarans, and my second type of power catamarans derived from them are thought to have some difficulty in finding comfortable marina berths. In practice, I find that my anticipations far exceeded the reality, and I have had a little increased cost, but no particular difficulty finding dock space, and that the catamaran hull is particularly better suited for anchorage, by virtue of its roll resistance and the level of comfort aboard. Anchoring out is a particular treat in my book. In short, if you took the considerable trouble to 'convert' a sailing catamaran into a power only catamaran, you would compromise off some of the finest advantages of the sail cat, while gaining little of the advantages of the modern power cat. A modern sailing catamaran cannot go very fast under power alone, but screams along under sail. Sailboats of all shapes have interior spaces already compromised for sailing, like low overheads and sail handling cockpits. These would be difficult to reconfigure to match the interior space utilization of a power boat. The difficulties of sailing are that you cannot ever count on favorable winds, and sailing catamarans are variously compromised in their upwind performance. If you can loosen up your schedule, shed your case of 'get-there-itis' and just go with the flow, the sail performance alone will get you wherever you would like to go, and if you are not after the speed of a planing power boat, catamaran or monohull. When the 'diesel wind' is used either because the wind is wrong or the owner is lazy, he gets the performance of a full displacement 'trawler' sort of boat, not such a bad way to go either. The tiny diesel engines already found on these boats can be given significantly more range by temporarily adding a modest amount of fuel bladder or gerry can storage for a particularly long jaunt without taking a huge penalty in handling and boat motion. With an unmodified, or slightly modified sail catamaran one can go anyplace today's power catamaran can go, albeit not on precisely the same schedule. The long deep ocean passages that only the larger power catamarans can manage are readily available to almost any modern sail catamaran.

Thanks very much for these valuabkle comments, Gary. So, in effect what you are saying is that if one has no hurry, one can forget the saIls and use the smallish diesel engines and potter along on the sailing cat, but thinking of it, as it were, a powercat? Rupert. On 13 Mar 2008, at 13:48, Candy Chapman and Gary Bell wrote: > > > Part 2: > > Two other major sorts of monohull boats are seen in today's > marinas. The full displacement monohull does not have a clear > derivative in modern power catamarans, which all utilize planing to > one extent or another. The monohull sailboat contributed sailing > rig and other traditional attributes to the far more recent > development of sailing catamarans, but it's hull form was generally > abandoned (with the possible exception of daggerboards). These > sail catamarans then evolved into today's second type of power > catamarans, retaining virtually none of the monohull sailboat hull > features. > > Finally, to converting sailing catamarans to power catamarans. > Why? Sailing catamarans have, by virtue of their sail rigs, > virtually unlimited range. Modern sailing catamarans are commonly > used for coastal cruising as well as routinely crossing oceans. By > virtue of their high sailing speeds, limitless range and their > unique maneuverability under power they are particularly well > suited to do so. In coastal and local cruising, sailboats of all > sorts use their engines -- and don't use their sails -- maybe 90 > percent of the time. Sailing catamaran hulls are similarly as > slender as my second sort of power catamaran, or even more so, and > use the slender hull minimized bow wake approach to breaking out of > the 'hull speed wave trap.' Note please that they lack the modern > power catamaran's 'semi-displacement' planing features of flat > bottomed aft sections and powerful enough engines to achieve > significant hull lift. They operate in strictly displacement > mode. The particularly small engines needed to only approach > displacement hull speed are designed into the hull with oodles of > compromises and trade-offs which have evolved over a considerable > time to uniquely suit the hull and engine combo. Adding a larger > engine will be very challenging in terms of the strength of various > hull components, size and shape of the spaces available, etc., and > without planing capabilities in the hull shape, will not give > spectacular improvements in top speed. Interior space utilization > in sailing catamarans has evolved into very efficient and effective > designs. Significant modifications to add larger engines or much > larger fuel tankage will force some very unhappy compromises. > Primary among these are considerations of weight and balance. > Catamaran performance, both sail and power, is incredibly sensitive > to both total weight, and to the presence of significant weight far > from the center. Orders of magnitude more sensitive than the > common monohull. Adding significant weight in upgraded engines, > and far worse in increased fuel tankage to an existing evolved sail > catamaran hull will cost large penalties in sail performance and > boat motion, for small gain in top speed under power and/or greater > range under power alone. The main fuel tank in my PDQ is probably > the heaviest item aboard, and occupies the bridgedeck space where > the center of gravity of the whole boat resides. Adding a large > fuel tank to a sailing catamaran would severely compromise its > behavior if it could not be correspondingly placed. Sailing > catamarans, and my second type of power catamarans derived from > them are thought to have some difficulty in finding comfortable > marina berths. In practice, I find that my anticipations far > exceeded the reality, and I have had a little increased cost, but > no particular difficulty finding dock space, and that the catamaran > hull is particularly better suited for anchorage, by virtue of its > roll resistance and the level of comfort aboard. Anchoring out is > a particular treat in my book. > > In short, if you took the considerable trouble to 'convert' a > sailing catamaran into a power only catamaran, you would compromise > off some of the finest advantages of the sail cat, while gaining > little of the advantages of the modern power cat. A modern sailing > catamaran cannot go very fast under power alone, but screams along > under sail. Sailboats of all shapes have interior spaces already > compromised for sailing, like low overheads and sail handling > cockpits. These would be difficult to reconfigure to match the > interior space utilization of a power boat. The difficulties of > sailing are that you cannot ever count on favorable winds, and > sailing catamarans are variously compromised in their upwind > performance. If you can loosen up your schedule, shed your case of > 'get-there-itis' and just go with the flow, the sail performance > alone will get you wherever you would like to go, and if you are > not after the speed of a planing power boat, catamaran or > monohull. When the 'diesel wind' is used either because the wind > is wrong or the owner is lazy, he gets the performance of a full > displacement 'trawler' sort of boat, not such a bad way to go > either. The tiny diesel engines already found on these boats can > be given significantly more range by temporarily adding a modest > amount of fuel bladder or gerry can storage for a particularly long > jaunt without taking a huge penalty in handling and boat motion. > With an unmodified, or slightly modified sail catamaran one can go > anyplace today's power catamaran can go, albeit not on precisely > the same schedule. The long deep ocean passages that only the > larger power catamarans can manage are readily available to almost > any modern sail catamaran.

gram rupert wrote: > Thanks very much for these valuabkle comments, Gary. So, in effect > what you are saying is that if one has no hurry, one can forget the > saIls and use the smallish diesel engines and potter along on the > sailing cat, but thinking of it, as it were, a powercat? > > Rupert. Yes. To use a sail cat in place of a slender hull power cat one gives up some interior space and the ability to power at higher speeds. The speeds will be similar to those of the large displacement trawler type cruising monohulls. Fuel economy will be splendid. In fact this is the way sail catamarans frequently achieve coastal cruising, sailing being more fuss and winds are frequently unfavorable. If you want the planing hull type of power catamaran performance, forget sail catamaran hulls unless you are willing to invest in producing a hydrofoil supported boat with a proportionally huge motor. It would probably be easier in such a case to start from scratch. Are you looking at all the mid forty foot sailing catamarans just now coming out of charter service? Me too. The Admiral and I are looking retirement in the face, and we have always dreamed of exotic tropical islands.... pretty much out of reach on our PDQ without Dockwise. Cheers Gary

Are you looking at all the mid forty foot sailing catamarans just now coming out of charter service? Something like that, yes, as it seems to be a sensible way forward. I have heard that there are also quite a few on offer at the moment. Thanks, Cheers, Rupert. On 13 Mar 2008, at 15:57, Candy Chapman and Gary Bell wrote: > gram rupert wrote: > >> Thanks very much for these valuabkle comments, Gary. So, in effect >> what you are saying is that if one has no hurry, one can forget >> the saIls and use the smallish diesel engines and potter along on >> the sailing cat, but thinking of it, as it were, a powercat? >> >> Rupert. > > Yes. To use a sail cat in place of a slender hull power cat one > gives up some interior space and the ability to power at higher > speeds. The speeds will be similar to those of the large > displacement trawler type cruising monohulls. Fuel economy will be > splendid. In fact this is the way sail catamarans frequently > achieve coastal cruising, sailing being more fuss and winds are > frequently unfavorable. > If you want the planing hull type of power catamaran performance, > forget sail catamaran hulls unless you are willing to invest in > producing a hydrofoil supported boat with a proportionally huge > motor. It would probably be easier in such a case to start from > scratch. > Are you looking at all the mid forty foot sailing catamarans just > now coming out of charter service? Me too. The Admiral and I are > looking retirement in the face, and we have always dreamed of > exotic tropical islands.... pretty much out of reach on our PDQ > without Dockwise. > > Cheers > Gary

gram rupert wrote: > Are you looking at all the mid forty foot sailing catamarans just now > coming out of charter service? > > Something like that, yes, as it seems to be a sensible way forward. I > have heard that there are also quite a few on offer at the moment. > Thanks, > Cheers, > Rupert. I suppose that the great surge in availability and acceptance of these fine boats in charter service must have been from three to five years ago, as there seems to be a real surge of them on the used boat market just now. In pricing them don't forget to factor in the cost of compensating for the hard use they have had, and be very selective about only buying boats from the few charter companies with high maintenance and repair standards. I likewise feel that these ex-charter type sail cats are better suited to long distance cruising than pottering about in one's home waters of a weekend, because they lack the power catamaran's turn of speed under power. The power catamaran probably also has an edge in interior space and creature comforts. If you look carefully you can find the occasional PDQ 34 on the used market, and whereas the initial price is higher than the ex-charter sail cat, that gap will close considerably if major systems need to be restored or upgraded. It is caveat emptor for both, with the charter boat bearing the largest risks. Again, cheers Gary

Wise words. Many thanks, Rupert. On 13 Mar 2008, at 16:21, Candy Chapman and Gary Bell wrote: > gram rupert wrote: > >> Are you looking at all the mid forty foot sailing catamarans just >> now coming out of charter service? >> >> Something like that, yes, as it seems to be a sensible way >> forward. I have heard that there are also quite a few on offer at >> the moment. >> Thanks, >> Cheers, >> Rupert. > > I suppose that the great surge in availability and acceptance of > these fine boats in charter service must have been from three to > five years ago, as there seems to be a real surge of them on the > used boat market just now. In pricing them don't forget to factor > in the cost of compensating for the hard use they have had, and be > very selective about only buying boats from the few charter > companies with high maintenance and repair standards. > I likewise feel that these ex-charter type sail cats are better > suited to long distance cruising than pottering about in one's home > waters of a weekend, because they lack the power catamaran's turn > of speed under power. The power catamaran probably also has an > edge in interior space and creature comforts. If you look > carefully you can find the occasional PDQ 34 on the used market, > and whereas the initial price is higher than the ex-charter sail > cat, that gap will close considerably if major systems need to be > restored or upgraded. > It is caveat emptor for both, with the charter boat bearing the > largest risks. > Again, cheers > Gary