In-Depth, Aluminum Boat Design & Selection, Part II
By Guest Writer, Colin Speedie
Index
Part I
Introduction
Turning the Dream Into Reality
Choosing A Suitable Boat, New Versus
Old
A Boat Built to Travel
Making the Most of Aluminum
Part II
Self-Defence in Harbour
A Practical Interior at Sea or in Harbour
Limits to Complexity
Are Spade Rudders Suitable for
Ocean Crossings?
A Practical Cruising Rig
Part III
The "S" Word—Stability
Anchoring in the Modern World
Self-Sufficiency in Power
The "C" Word—Corrosion
Electrical Systems and Aluminum Boats
What Has Worked So Far—Domestically
Self-Defence in Harbour
Those of us with aspirations to cruise in higher latitudes tend to focus on obviously important kit—sails, ground tackle, engine—but sometimes at the expense of simpler and less apparent elements. For example, some of our time will still be spent in port, but that almost certainly won’t be the sort of haven we’re used to in more developed areas. Over the years a few fishing ports have put in small pontoons that yachts may be permitted to use, but as often as not if you are seeking shelter from bad weather (and you will be, at some stage) it will mean rafting up with fishing vessels and work boats. And here it will be just as important to be prepared for port as it would be for an exposed anchorage.
Production boats these days tend to be designed for marina dwelling, not mixing it up with the big boys—mooring cleats that are too few and too small with inadequate fairleads, and often poorly secured to the deck. A bad night in a small fishing port with a big storm surge finding its way around the corner will soon find any weaknesses. And when F/V Cruncher arrives with an exhausted crew at 0300 and berths alongside you, will they be able to spot your cleats, or even drop one of their hefty lines around one? If not, look out, as they will have to make fast to whatever is most obvious, and not necessarily what you might have chosen.
The answer is to scale up accordingly, both above and below deck. For our new boat, we have specified oversized welded cleats, and added a huge additional pair in the bow, where from previous experience we know we’ll need them. We have no fairleads, simply wide and open access to the cleats, allowing all angle attachment. Extra cleats also allow one warp for one job, essential when additional warps such as shore lines are required.
At least a couple of really long warps are essential, especially in areas with a high rise and fall of tide, to make fast to bollards or rings on the pier. Robust protectors for these (we use reinforced loo pipe) where they pass over the edge of the pier, will stop chafe devouring them in a few hours. We’ve even seen warps with chain ends for this purpose, and didn’t think that was overkill at all.
A must is a robust fender board, especially when alongside vertical pilings, allowing the fenders to remain in place. It is possible to link sausage fenders into a horizontal daisy chain in normal conditions, but once your boat starts to surge back and forth, nothing but a fender board will do—they are also ideal when alongside barnacle encrusted jetties, too.
Our boat is also having a welded, unpainted rubbing strake just below deck level, for those unfortunate moments when a fender slips out of place, and the topsides grind against a dock, which should save paint and pride in equal measure.
For when the storm hits, you’re on your own, and preparation for every
eventuality is vital. And if you have made everything as strong as it needs
to be, with the gear to back it up, then you will be ready to face the
challenge, confident that you and your precious boat will still be there
in the morning.
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A Practical Interior at Sea or in Harbour
A boat designed for extended offshore cruising has very different priorities from one designed for the occasional weekend aboard or a two week annual holiday. The former, is, after all, going to be your home, and you will be spending the majority of each year aboard at anchor or in harbour. The emphasis therefore shifts towards practicality, stowage and liveaboard comfort.
The OVNI comes with an aft cockpit, so that to some degree dictates the layout below. We have made a significant number of departures from the standard layout, starting in the bow area where we have done away with a heads and shower module, replacing it with stowage and a small fixed workbench. Years working on charter boats and sharing cabins with heads units made this an easy choice! The standard forward cabin has an offset double forward to port, but this loses width due to the shape of the hull, so we have opted instead for a big central double, lots of stowage and a small writing desk. This is a bedroom, in effect—forecabins are of limited use at sea (unless you like being flipped like a burger), and we want a civilised, comfortable sleeping compartment for when we are in port.
The saloon is very much as per the standard OVNI layout, which is largely governed by the presence of the centreboard case. Sensibly Alubat make a virtue of this, offsetting the saloon seating and table to port, and using the case as the backrest of the central seat. We have asked for the chart table to face forward (it normally faces aft—which just feels wrong to us), and have altered the corner angles of the saloon seating to ensure that we have two good sea berths as a result. Although we are more used to having an island galley aft, this is not an option, so we’ll have to get used to a galley down the starboard side of the saloon—let’s hope it works well.
Aft of the galley we have opted for an enlarged head and shower, with full standing headroom. Again, we want a home, not a compromise, and with plenty of grab rails should have a heads that works as well at sea as in harbour. This modification loses us space in the starboard aft cabin, but we had already factored that in. Instead of the standard double berth in this cabin, we have opted for stowage and space for all of our vital services. What we want is instant and unobstructed access to all equipment that will need regular servicing—the watermaker and heater, for example—as our motto is “if a job’s easy—you’ll do it”.
A big double berth aft to port will be for guests, as well as being split as an additional sea berth. One of the things we are looking forward to most is company along the way, and this comfortable double ought to make even the most picky sybarite feel at home!
Wherever possible we have specified equipment
that we know will be dependable and easily serviced. Quality equipment
always pays for itself in the long run, so it’ll be Force 10 in the galley,
Lavac in the heads and Webasto for the heating system. We are, after all,
going to have to live with our choices day in, day out, and so we’re spending
good money now in the hope we shall save it in the long run.
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Limits to Complexity
We are now at the final stage of selecting our navigation systems, and as new products are being launched all of the time, have decided to wait until the last minute before committing.
But to some degree the choices are being made for (or taken away from) us, as so many of the manufacturers are moving towards integrated systems, reducing the available options for those of us who like to pick and mix the best kit from different stables. For example, it is now virtually impossible to buy a stand alone radar, as everyone is moving towards combined radar/plotters using their own Ethernet type connectivity.
Since the 90’s I have professionally skippered my own yacht on research projects, and have for the last six years used a laptop linked to a GPS for all basic navigation. Being only modestly computer literate has never been a major shortcoming, and although they have simply been fixed to the chart table with Velcro, we have never lost one to damp or rough handling. If you are used to computers at all, they are quick and intuitive to operate, and their large screens offer a good view of the charts. By comparison, I recently skippered a boat with a brand new plotter, and didn’t like it at all—the screen was too small, and the operation was clumsy and slow. And having recently watched two experts trying to sort out a problem aboard a boat with an Ethernet link between instruments and plotter—two sets of software, and by their own admission, a tendency to crash on a regular basis—I wonder whether this is really the way forward?
The new and the old both have their places
Of course PCs can go wrong, too—we carry a spare as back up, as well as up to date passage charts and pilot books, just in case. And as I learned to navigate long before we had any electronic luxuries, if I have to go back to dead reckoning in an emergency it should not a big deal. But with our laptop we can integrate weather files from the internet, AIS information, tidal streams and Navtex at far lower cost than a half way decent plotter. And we’ll stick with an NMEA interface which at least will allow some basic diagnostic tests to be run should it go down 1000 miles from the nearest dealer.
The one thing we have committed to is an Echopilot forward looking echosounder. We used an Interphase Twin Scope for the last seven years, and found that the ability to scan for depth and obstructions ahead of the boat was indispensable, especially in poorly charted waters. But Echopilot sensibly offer the option of a custom transducer housing made from solid aluminum billet (essential for us with our aluminum hull) which will enable us to pull the transducer prior to taking the ground, one of our main reasons for choosing an OVNI. Having heard nothing but good reports of their products, this was an easy choice to make.
And while
we’re on the subject of holes in the hull, we think the fewer, the better,
so we’re not having a through hull speed/log unit. Paddle wheel logs are
unreliable, and often tricky to calibrate accurately, and as a Furuno WAAS
GPS reads speed as fast as a log, we shall use a repeater in the cockpit
as a speedo, and the trip facility as a log. We are well aware that this
is “over the ground”, but we can compensate for that if needs be. And if
all of the electrics fail, then we have a lovely boxed Walker Knotmaster
towed log that has followed me from boat to boat over the years. There
should be a limit to complexity!
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Are Spade Rudders Suitable for Ocean Crossings?
As I mentioned in a previous posting, one of the most attractive features of our new OVNI is the protected rudder, which we think is an essential feature for a long distance boat. However, the three cruising boats I have owned over the last 25 years were all equipped with balanced spade rudders with no supporting skeg. And as in the last of the three I had covered over 60,000 miles with no problems, I had, in fairness, few reasons to doubt their strength and fitness for long distance cruising.
This last boat, like all commercially registered boats in the UK, has had to undergo a full, out of the water, structural survey every five years, and in the most recent survey the rudder and its fittings received an A classification. With the rudder being balanced, the immense and repetitive loadings it is constantly subject to are seldom felt through the wheel, but we know they exist, so each year we have conducted a careful examination of the shell looking for cracks caused by stress. In addition, every few years we have dropped the rudder, to examine the stock, the bearings and neoprene stuffing gaiter, but we have never found any evidence of deterioration or stress. So when we lost our rudder off the South Cornwall coast this summer, it was, to say the least, a shock.
Evidence of crevice corrosion and metal fatigue
As we were within half a mile of the shore, the priority was to gain some sea room. Fortunately we have prepared for such an eventuality, and with our flexible cutter rig have always managed to work out a combination of sails and warps to make progress in the right direction. So we furled the yankee, backed the staysail, and using the main to bring her head up, we turned her out to sea. With the wind being light we were making little progress, so we started the engine and brought our speed up to three knots. Although we were swooping around rather a lot, the combination of backed staysail and pinned in main worked effectively, so we didn’t need to trail a warp. A VHF call to the Coastguard to explain our predicament ended with the reassuring message that the local Lifeboat was being launched—with passengers aboard they were taking no chances.
The Lifeboat arrived and confirmed that our rudder was, indeed, missing—just as we had suspected. They passed us a drogue to be towed astern, and then a tow line and we were off. We had already dropped our sails as instructed and so had no way to balance the boat, but at a towing speed of five knots or more we were really swinging around on the limit of control even with the big drogue out, making it abundantly clear just how tricky it would be to handle a boat without a rudder at higher speeds.
Two days later she was out of the water, and we could see for the first time the extent of the damage. The 4” rudder stock had sheared off about 6" down from the hull, inside the rudder blade where no amount of inspection could have discovered a problem. Eventually a surveyor visited on behalf of our Insurers, and after some deliberation drew attention to two faults. One was that there was evidence of crevice corrosion at a weld where the shaft had been sleeved to allow the rudder to taper, which was where the stock had sheared. The second was the unmistakeable sign of “beaching marks” indicative of metal fatigue plainly visible on the sheared stock. So our claim was rejected on the grounds of “wear and tear/metal fatigue”—another shock.
Many yachtsmen are unaware that stainless steel is not corrosion free, and should not be constantly immersed, which can cause the surface oxide layer to break down allowing crevice corrosion to gain an entry. GRP rudders are notorious for becoming waterlogged, and in the anoxic, polluted solution inside the shell, corrosion will soon go to work on even the best marine grade stainless steel. Ally that to the metallurgical changes that the weld itself would have caused, the fact that the step down in size would have effectively created a “hard spot” (and thus a weakness), coupled to the continuous loading and flexing inherent in this type of rudder where it exits the hull, and you have, over time, a recipe for disaster. The remarkable thing with ours may be that it lasted as long as it did.
So
now I’m convinced that spade rudders are unsuitable for long distance offshore
voyages, not just because many new production boats have stocks made in
unsuitable materials (which they undoubtedly do), but also because there
may be a potential time bomb waiting to go off even in a well built older
cruiser. And whilst we were lucky, and all went well, I could think of
a thousand occasions in the past when the consequences might have been
very different—and that simply rules them out for me.
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A Practical Cruising Rig
Here in Europe the standard rig for most yachts sold as “cruisers” is still the sloop, usually with a large overlapping genoa of 130% or more. That might be fine in sunny sheltered waters with an army of gorillas to help out, but is less than ideal for shorthanded crews sailing in windy and exposed seas. This is when the ability to shift gear to suit the conditions by reefing swiftly and safely is far more important, and the true cutter rig comes in to its own.
So we have opted for a roller furling yankee, coupled with a hanked on staysail on a detachable stay. The mainsail is fully battened, using Harken cars and mast track—simply the best there is. All reefing will be by single lines lead aft to the cockpit handled by a power driven winch. The aim is to achieve (as far as possible) the ability to reef all sails from the cockpit with the minimum of fuss.
We have specified spare halyards for most sails, believing that the extra complexity and windage should be more than compensated for in terms of safety and reliability. This is not all that awkward to achieve—although our rod kicker (theoretically) does away with the need for a topping lift, we’re still going to have one as it will also double as a spare main halyard. The spinnaker halyard is having an extra long tail, to double up as a lifting halyard for our dinghy, and also so it can be deployed should we have to rescue anyone from the water. As this halyard is led aft to the power winch, this should prove a useful and practical feature.
All OVNIs are supplied with Sparcraft spars, which seem robust and well finished. A full set of folding mast steps are being fitted to simplify regular rig inspections aloft, conning the boat in shallow water and in case of the need to make emergency repairs. As OVNIs are true centreboarders, the mast is mounted well forward above the pivot point of the keel to ensure good balance of the hull and rig. This means that the boom doesn’t sweep the cockpit, a useful safety feature on any cruising boat. For the first time on any of our boats we have specified a boom brake, in our case the new model from Wichard. This is a clever looking device, derived from climbing equipment, and has no moving parts, relying solely on friction to slow the travel of the boom and will double, we are told, as a preventer when fully tensioned. It will be interesting to see how well it works.
The rig is well stayed,
in the best traditional cruising manner. Many modern yachts are going over
to one single chainplate per side to handle all standing rigging, combined
with aft swept spreaders, features that don’t appeal to us on a cruising
boat. In contrast, Pèlerin has fore and aft lowers giving vital
support where it matters in the bottom panel of the rig, combined with
parallel spreaders that reduce chafe on the mainsail, and make it easier
to reef the main off the wind—a hardship at times with a fully battened
main even with parallel spreaders. Some crews find the running backstays
on cutters a nuisance, but we like them as they stiffen the rig up immensely,
and are very reassuring in strong winds. Twin standing backstays offer
a simple and dependable failsafe in the event of one failing. All in all,
it’s a simple, strong, belt and braces set-up in line with our overall
philosophy of safe, self-sufficient cruising.
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