The pro’s and cons of displacement motorboats and planing motorboats.

First a background check: I come from sailing having started in the motor-sailor version of the very robust 40 foot Warrior. Nearly unbreakable and ideal as a starter full size boat.

After four years learning I graduated to a real sailing boat….a Beneteau 44 which was a total contrast….green, very saily, fast and fun….also four years.

End of the tale for sailing.

Change of circumstances forced a switch to a motor boat…..blue of course and 48 foot Dutch Sturier steel vessel built by Volharding Staveren with cruising speed of 9 knot…very impressive speed for a sailor. It was a model of packaging with three double cabins, two bathrooms in and outside helm position, twin engines and massively robust in any seas.

Problem was that without stabilizers the Southampton to Cherbourg trip in the usual South West wind became very uncomfortable due to uncontrollable rolling in anything above force 6 winds. However it is the only vessel I sailed on which experienced a force 10 wind (from behind) about 8 miles north east of Cherbourg. Discretion ruled….back into it to port, the crew was ill but morale recovered after the third bottle of wine.

Sturier 54 footer with stabilizers

To address the rolling issue I switched to a 54 footer….same yard….also displacement…. about 40 tonnes (and blue of course) with two Perkins 225Hp engines and the magic of fin stabilizers. It was a superb boat. We went all over, including an extensive period in the Med as far East as Tunisia and Malta. She handled any Med. weather with aplomb.

Sturier Yachts 675 OC

Even grander ideas emerged and I traded to a 68 foot Sturier…70 tonnes…. and still blue…… specially modified for deep sea use with extra 20 cm on the keel…..massive rudders and oversized stabilizers. All to deal with the North West winds down the Spanish/Portuguese Atlantic coast and the huge swells that produces. Again magic and although official cruising speed was 9.8 it surfed at up to 15 knot….still on autopilot…It has that much underwater stability and resistance to being thrown off course. Again down to Med…Based in Spain but the berth lease cost a bit less than 300,000 euro without regular tax and service charges. Renting was out of the question…it was the good time in Spain!

We cruised up and down the East and South coast and to the islands, Sicily. Tunisia and wintered in Malta. Back up the Portuguese coast two years later…. rather more splashy against the wind but we always made tea and ate hot food. We then based her in UK for a season in spite of quite high berthing cost and eventually in Holland where costs are about one third of that on the UK South coast. There the problem of size started to emerge. Box moorings for 21 metres with twin poles were awkward and not easy to find and my Dutch crew (my wife) found the fenders too heavy. We did frequent trips between Holland and UK …always overnight… crossing very busy waters alongside and passing Rotterdam-Approach traffic zones. Always safe and 90 per cent of the trips in great comfort with one exception….into a Force 8 South-Westerly 20 miles North of Dover with wind against tide making us divert to Ostend. It was meant to be recreational after all. Green seas were coming over the top regularly and it was the only time we failed to complete a voyage on plan in this vessel.

The smaller “Vlet” for the IJsselmeer in Holland was a strategic mistake

However while the 68 foot boat was in Spain and to ensure we had something to use in Holland which my wife very much enjoyed, I bought nearly new demo model of a Dutch steel Vlet. Weight about 14 tonne…..blunt at the bow and ideal for use in canals. It was a very nice boat with superb interior for a couple with a good bedroom, superb cooking, washing and toilet arrangements, enormous living space and twin helm positions.

However in the end a strategic mistake as we were based in Volendam in the South of the Ysselmeer and most trips required a 25 to 30 mile trek up or down the lake. With the prevailing wind South West it meant an awful lot of going into the wind on at least one of the legs of the trip. The Ysselmeer may be called a lake now (was sea 80 years ago) but it has vicious short waves once the wind goes above 20 knot. With its blunt voluminous bow the Vlet tries to climb every wave and on the beam it of course rolls like all displacement vessels do without stabilizers. She has now been sold to a very happy new owner who has no intention of sailing in open waters.

The new Sturier 500 CS for sailing in Holland

Advancing decrepitude triggered a decision to go back down the scale again and the 68 footer was swapped for a highly computerized and very advanced Sturier CS 500 which is a 50 footer…. all still the same yard….but not in blue…. (Fiat 500 “Funky-White” instead). Years in the Med finally made me overrule friends and spouse…. the sea in the Med is very salty and even the fresh water stains are just too obvious on the blue. You never have enough air-conditioning capacity for August weather either and the dark blue loves absorbing energy. The CS 500 is currently based in Holland but possibly scheduled to go back to the Med Spring 2015. Thus far the displacement motor boat part.

Planing motorboats

This brings up the faster non-steel part of the story. Once the big boat was back in North Europewe had no boat in the Med so we decided on a runabout. On impulse I bought a new 8 metre fisher type boat…twin shaft drives thrusters etc. etc. It lasted exactly three months. Once it went over 23 knot it started to scare me and She-Who-Must-Be-Obeyed was not impressed. Just getting to the front for mooring was an effort well beyond my tolerance level. In any case it failed the acid test…any boat that moves when I step on it is too small.

Undaunted though we switched tack and later bought a second hand Beneteau 13.8 with two times 480 Hp….. A very well specified boat with excellent sea keeping and first class accommodation given the size (three double cabins, two bathrooms, good saloon and well equipped fly bridge). You can see what a well-developed boat produced in great numbers does for quality at a modest price. Still in service…. Based in Denia…just back from a two day trip to Ibiza…3.5 hour each way….into, and on return backed by, force 5 North East wind.

This concludes the facts in the story. Now the opinion:

Firstly the speed of the planing vessel is the outstanding positive….Barcelona to Denia in one daylight stretch. In bad weather 20 miles is one (endurable) hour from port in most of the Mediterranean East Coast Spain You are rarely more than that from a safe haven The fly-bridge is magic in half decent weather. Manoeuvrability with engines and bow thruster only, is great but the snag is that with this enormous power on a 12 tonne vessel the reaction to minimal gear shifts (forget about using the throttle while manoeuvring) is so extreme that you often get an overreaction. This is not at all helped by the 1.5 second delay on gear shift movements.

The fact that it is so light of course means that almost every marina can lift you for repairs or under water maintenance and there are plenty of service outlets and spares for this kind of boat and the VOLVO engines and all workshops can handle them. Not so good is when you look under the floors and see the relatively undercooked hose and water handling arrangements including bilge pumps

BUT…..there is no tea making or cooking under way. And you have not to believe that flat calm sea state is anything but an exception in the Med. The ride is almost always bouncy and very noisy. Sleeping under way is mission impossible.

Fuel consumption is a treat to the Saudi’s…. 100 litres per hour at 18 to 20 knot cruising speed…probably double at max of 30 knot. Slow cruising is only possible in flat calm when the temptation is to do just the opposite. “No-Wind” does not mean “No-Swells”. Sea movement can stem from storms as far away from around Sardinia or a distant Mistral which influences weather all the way to Minorca passing on swells till they hit the main land whilst local conditions appear benign.

Going from Denia to Ibiza and back in the Beneteau uses 700 litres at a cost of 1000 euro…enough to drive you back to sail! The big boat 68 foot took 6 hours and burnt 600 litres. With my 54 foot Sturier it took 7 hours and burnt 400 litres there and back. With the new 50 foot boat with more modern engines it might take nearly 8 hour but should burn only just over 300 litre. It takes more time but in a hurry we need to go Easyjet. The ferry is faster but for 4 people it will cost about 800 euro too. On all three our own slower ships we could eat and drink on the way and listen to music. And the ladies can go and have a very nice restful sleep as well and be fit for the festivities in Ibiza once there. More usefully still we do not have to worry so much about the weather forecasts. Beam winds are perfectly manageable up to 30 knot and stern winds are very welcome even in the smallest of the three. Winds here are regularly around 20 knot during the day….usually North-East or South East in summer. The basic wind is enhanced by on-shore breezes from about noon to 7 or 8 at night. The late afternoon fading of the onshore breezes makes returning to a berth later in the day much more comfortable and with a slow boat it is always best to depart early when the wind is at its lowest.

With very powerful hydraulic bow and stern thrusters manoeuvring the displacement vessel into a berth is different to the Beneteau but once pointed into the berth, engine movements back or forward far more controllable. Windage is obviously less for the heavier, lower profile, vessel. The last few metres of mooring stern-to is just easier with a much lower powered engine and once the fixed length-sprung, stern lines are handed to you by the marinero and on your cleats, you can put both engines forward on idle and the ship will hang straight (without either breaking the line or the onshore bollard). It gives time to get the sunken bow lines up forward and tight and then spring back as taut as possible once you go back to neutral. With the high power engines and low vessel weight this is just not possible and with one engine it can become a drama as it will pull the vessel whichever way the neutral engine is.

And once calmly in port the sloshing of water against the hull is certainly a great deal less noisy against steel than epoxy/fibre hulls.

Going into a seriously heavy sea the chances of doing structural damage to a 50 foot, heavily framed and girded 35 tonne steel hull powered forward by 300 HP are close to zero. Not so in an epoxy/fibre hull of 12 tonne powered by near 1000 Hp.

Likewise the chances of shaking something loose at 9 knot in a heavy hull are a great deal less than at 20 knot in a lightweight plastic hull especially as double clipped hoses are not in the build programme.

Night boating at 20 knot in an epoxy/glass boat has to be far more risky than proceeding at less than half the speed in steel, if rogue objects present themselves in the water. More importantly the radar stability is heavily dependent on the stability of the vessel itself. At night in a motor boat anything not on the radar or with a light does not exist for all practical considerations. Half the time the vibration and movement in the faster boat is such that dealing with buttons (or mouse clicks in the case of the 500 footer) becomes very critical. In anything around or above Force 5 winds I have difficulty dealing with instrument and radar buttons and settings accurately. And again going slower is not an option in the Beneteau ….all stability disappears at displacement speed in any wind from the sides and in a following sea, broaching becomes a serious possibility at low speed. Night sailing would actually be ideal as the wind drops and the traffic is minimal if you are used to the North sea….but not at speed…..you will not see anything in the water other than ships and even then the fishing boats are as unpredictable as they are in the North sea….only with fewer or the wrong lights.

Enormous positive for the Beneteau is the fly bridge and really if displacement vessels want a part of the Med-Sea market that has to be an essential. Furthermore proper Besenzoni style passarelle is an absolute must. If the 50 footer is to come to the Med this will have to be retro-fitted…..no matter the aesthetic considerations against.

The Med style boat is meant to be used as most locals do…..stay at base…. go an hour round the corner and anchor in a scenic bay and spend the rest of the day sunbathing and drinking…. go home after 7 in the evening when the wind drops. Go at full speed and close to land so your friends on the beach can see your stern wave and be impressed on how much money you have to burn and park up back in berth with no wind.

If you want relaxed travelling and go serious distances there is only one option …..Displacement… and live with the absence of the upper deck or try to see if there is a version that gives you a fly-bridge for the days you want to boat like a Spanish resident.

Me personally…….I’m now a confirmed, steel displacement man any time…. Now that I have seen both worlds in both North and South Europe the case is made in favour of the CS 500….even for the Med.

Sipko Huismans

29 August 2013