SOHVI: Performance and Improvements

Sea Legs for SOHVI

Despite having been afloat for most of the summer,  last weekend was the first opportunity I have had to dry SOHVI out and make a few changes.


First and most obviously,  I set up a pair of beaching legs acquired courtesy of eBay.



These legs (type PL30) are made by the Yacht Leg Company and have the great advantage of being telescopic, which makes them easy to stow in the starboard cockpit locker when not in use.

Drying legs may be of limited use elsewhere,  but here with 10m + tides,  the ability to take ground safely from time to time is a real bonus.   They are also very useful when laying up the boat ashore.


Some Summer shots:

A few shots of Brittany, August 2017

Performance under power

A summer of cruising means that our new Vetus diesel is now fully run-in.  During this time I have been unable to reach more than 2,650 rpm,  compared to the designed maximum of 3,000 rpm.  Consequently I decreased the pitch on the Variprop by approximately 1″, to 13″ (diameter is 22″)



Today we went out to conduct some speed trials and found that maximum rpm is now exactly 3,000 rpm.  Whoopee!  So what does all this tweaking mean in real life?  Let’s look at some data:

Doing the math:

I commented previously that the performance curves for the Perkins 4.108 and the Vetus M4.45 were very similar.   A quick conversion of units allows one to make the following comparison:




The Vetus is a little better than the Perkins below 2,000 rpm and much the same up to 3,000 – which is the maximum permitted,  generating 42 hp.


The following speed v rpm chart represents the average of a two way run on reciprocal course in reasonably calm conditions:

Objectively that is slightly slower than I expected,  but subjectively it seems fast enough, with the quarter wave right at the stern of the boat.  Any faster and we’d be going uphill!  The Vetus engine is also noticeably quieter than the Perkins (although I have not been able to quantify that with a db meter).


Interestingly the reduction of slope at approximately 2,000 rpm, or 6 knots, coincides closely with the theoretical maximum hull speed of 6.6 knots calculated using the empirical formula of 1.3 x √LWL (26′).  It may also reflect the fact that a flat-blade feathering propeller is not as efficient at higher output as a true helical screw.  This same propeller used on our old boat would typically incur a reduction of approximately 8% in top end speed compared to the fixed blade propeller.

Fuel consumption figures are more difficult to compare meaningfully.  Vetus provide the following data for the M4.45


Initially I performed a straightforward conversion from these figures into litres per hour,  but the end result suggested a consumption considerably higher than other MS33 owners experience with similar sized engines.  (I am indebted to Svein Lamark who first highlighted this difference – see comments below).



An exchange of emails and telephone conversation with Vetus UK clarified the situation.  The consumption curves are theoretical in so far as they assume the engine is fully loaded at any given rpm.  The reality of course is that for a given pitch,  the engine is only fully loaded at one particular rpm, which in our case is 3,000 rpm.   At lower rpm,  the engine is nothing like fully loaded,  or to put it another way, the propeller is absorbing considerably less horsepower than the engine is capable of delivering at these lower rpm.   The actual amount of power absorbed will vary considerably depending on the hull design, displacement, sea state and other variables.  Consequently real-world consumption at lower rpm is likely to be considerably less than I originally calculated.  Vetus provided the following data as to what a ‘typical’ installation might return and which clearly illustrates the point above.






Fully loaded at 3,000 rpm,  the M4.45 will consume in excess of 10 litres per hour. However,  partially loaded at a typical cruising rpm of 1,800 rpm,  the consumption is likely to be in the region of 2 litres per hour.   That very significant difference demonstrates the real cost of pushing a hull past theoretical maximum hull speed: it is much more efficient to motor at a relaxed cruising speed.    Interestingly the 2 litre per hour figure Vetus suggest above is very close to the 2.2 litre figure Svein achieves with his 49hp Yanmar installation (see comments below).

There is only one way to accurately report fuel consumption and that is to log fuel used against hours motored over a variety of conditions.  In other words,  to keep a decent log of fuel consumed during a season of cruising. Ask me in a year’s time and we’ll see whether I have been diligent enough to do this 🙂

It is highly likely that all of this simply serves to confirm what most MS33 owners will know already;  that a cruising speed of approximately 6 knots is undoubtedly the most economical way to make progress.

Final Thoughts

Should I have left the pitch unchanged?  We were obtaining close on 7 knots at 2,650 rpm,  which was possibly more efficient.  However,  it created some black smoke suggesting the engine was overloaded and in the longer term I am comfortable that the engine is now set up as it should be.

Had we not experienced a gearbox failure,  I would probably have kept the Perkins for as long as possible and been entirely happy with it.   Having made the change, and despite the fact that the performance is really not much better than the Perkins,  subjectively the experience is much nicer: the Vetus is undoubtedly quieter,  smoother and cleaner.  More importantly we are achieving the same performance as the old Perkins, but with the benefit of a feathering sailing propeller. Losing 75kg of weight has probably helped too, both in terms of sailing performance but also in our ability to carry all the usual cruising gear without depressing the waterline too much!

Posted in All the posts, Mechanical Stuff | 7 Comments

Sullom Voe is now on the market

George has contributed to our posts with information on wash boards etc. and now is selling his pride and joy.

For more information and loads of pictures go to

This is a well equipped boat at a good price. It even has beach legs which I spotted in an old post Sea legs but did not know that the boat was Sullom Voe.

Fjord MS 33 on Sea Legs

Fjord MS 33 on Sea Legs


Zooming in on the beach legs here is an image that might be of interest to some of you.

Beach legs on a Fjord ms 33

Posted in All the posts, Fjord MS 33 For Sale | 1 Comment

SOHVI: Living with SOHVI – first impressions

Guess what? – it turned out OK!

Despite having owned SOHVI for slightly over two years,  I have not had the opportunity to sail her in ideal conditions – until now!    Our original delivery trip back to Guernsey in 2015 included a lot of motorsailing against contrary headwinds.   So this summer’s launch was always going to be interesting.

First and most importantly the Vetus appointed engineer signed off my engine installation with some complimentary remarks – which was hugely gratifying.  I now have a fully functioning and warranted engine installation.  Based on that we took off on a short one week shake-down cruise with a 30 mile jaunt to our neighbouring island of Jersey (main picture above) and pleasingly almost everything worked as it should.   Last week we set off for a few days in Brittany and had a glorious sail for the 55 miles or so with the wind just astern of the beam.   I always had a slight worry that perhaps we’d bought a boat that was not going to be as rewarding to sail as our last boat – and although not as fast,  I was delighted to find we have a nicely balanced proper sailboat in SOHVI.  Here’s us heading for Ile Hébihens just west of St Malo:

Wouldn’t it be great if every sail could be as relaxed and as rewarding?!

Capturing the ambiance.

There’s something about sitting aboard late at night,  with the lights dimmed,  that makes everything look so cosy.  I tried a few arty photos,  but failed miserably to capture that certain ambiance.  These convey just a hint of that:


One of the things I came to hate most during the first few weeks of ownership was the ventilator fan above the galley – I invariably ended up hitting my head on it.

This combined fan and downlighter is sooo much kinder on the head – and more useful as a light too.


There’s still a long list of things to do, not least of which is rigging the asymmetric spinnaker, adjusting the pitch (finer) on the propeller and sourcing some beaching legs,  but we are getting there.   The intention is to take off somewhere for much of August and see where the wind takes us.  If the weather for the rest of August is like the beginning,  then there’s not much hope of that.   Fingers crossed for some better weather soon!

More pictures soon 🙂

Posted in All the posts, General Improvements, Journeys, The Boat Details | 2 Comments

Hope for Daphne

The wooden 36′ MS Daphne has been derelict in a sorry state the last years. There seems to be hope. She’s been sighted on a wharf at Killingen, Oslo, seemingly there for repairs 😀


Posted in Finding the Fleet, MS33 sightings, Uncategorized | 1 Comment

SOHVI: Back on the water!

SOHVI is back on the water.  Hooray!    However,  don’t confuse that with the assumption that this project is finished – it’s not,  as there is still much to do,  but it’s a huge step forward psychologically 🙂

Any boat owner will know that there never seems to be enough time to complete the long list of ‘to do’ items before launch.  And so it was with SOHVI – the boat was barely ready.  Last minute jobs included adjusting the pitch of the propeller and polishing the hull – the deck is still filthy (recommendation: never ever renovate anything under a tree!).

The propeller is a 22″ diameter 4-blade feathering Variprop made by SPW in Germany,  supplied some time ago for our last boat (approx 38′).   The shaft diameter (1.5″), taper (1:15) and rotation (RH) are all the same as the MS33 and so I asked the lovely lady at SPW to run some calculations for me.  “It is perfect” she said;  “You need a 22″ diameter propeller and 14″ pitch”  which is well within the range of adjustment.  Excellent!  That means we can experiment with a feathering propeller rather than being stuck with the fixed 3-blade originally installed.  Personally I think the pitch should be more like 13″,  but we’ll try it and see.

An unseasonable gale blew through which caused us to delay the lift by 24 hours,  but we finally launched on 7 June.  Here’s the sequence of events:


I’m particularly pleased with the mast support built into the radar pole – that has proved very useful for transporting the mast on top of the boat.

48 hours after launching we finally got the rig up: suddenly the boat becomes a yacht once more and somehow just looks so much better for it:

(I think I need to rake the mast back a few degrees to look better)

If you look closely you will notice the SOHVI is missing lifelines and bow roller – these weren’t ready for launch day.   Geoff Brown has performed artistry in stainless steel by creating a new double-roller stemhead fitting which carries the chain rode and nylon rode either side of the forestay.   The new lifelines should be here within the next week.


The new Vetus diesel starts superbly.  I am awaiting an inspection by their nominated engineers to confirm that my installation is acceptable,  allowing the warranty to come into effect.  One glitch I discovered immediately after launching is the cockpit gearshift connection is reversed:  pushing the lever forward engages reverse gear.   Oops – I’ll sort that next week before the engineer comes 🙂

We have still to load all of the stuff that turns a boat into a floating home: crockery, cutlery, bedding,  etc etc,  but suddenly it feels much more real!  All we need now is for some proper summer weather… 😎

Posted in All the posts, General Improvements | 5 Comments

SOHVI: Holding tank

You may recall my earlier post detailing the installation of a holding tank – well that is another job I have finally finished.  The tank just fitted inside of the old panel line, which made matters simpler.  Here’s the sequence of events:


I’m not a fan of using wood stain on plywood,  and I seriously considered fitting the new panel in white, but on the basis I can always paint it white later,  I thought I’d firstly try to match the colour.   In the end I used one coat of rosewood stain (teak stain was too dark) followed by 6 coats of satin varnish, which came pretty close to the colour of the original timber.

In terms of serviceability,  all of the top connections are accessible by removing a panel above the top shelf…









… and the bottom connection (which is only hand tight) can be reached through the white inspection hatch.






That’s an extractor fan mounted under the deck vent.  Just to make life a little more acceptable,  you understand 😷!

Posted in All the posts, General Improvements, Uncategorized | 3 Comments

SOHVI: Tidying up the rubbing strake

“Was the hull damaged?”…


… that is a question I have been asked more than once during my ownership of SOHVI.  No – definitely not!  She had a good survey report when we bought her and the hull is fine.



The reason for that question is that the timber rubbing strake on the starboard side had developed a kink.  It seems unlikely given all the fastenings,  but the strake had developed a bend across the width of the board – something that would be impossible to achieve if you tried to bend it deliberately that way.  Anyway,  it spoilt the smooth lines and snagged the eye whenever one looked at it.  So off it came :-).


Having taken the front section off,  it seemed logical to do the same to the aft section.  I’m not sure whether at some time in the past the boat was consistently moored with the starboard side exposed to the weather &/or sun,  but interestingly the port side is fine – so I have left that alone.  Here’s the boat ‘naked’ and with a quick colour change from brown to navy blue:



Once removed,  it was easy to see the pronounced kink.  I had originally thought that the timber was iroko – which is notorious for warping – but compared to my iroko caprail,  this is darker,  which suggests it really is teak (but see comments below).


Now – the dilemma was whether to replace the timber entirely,  or refit the original once repaired.   Given that the port side was fine,  replacing the starboard side with new timber would look obviously different.   The timber was basically sound – other than a small area near the stern post,  and it would save a considerable amount of work if it could be re-used.  Drastic though it seems,  the solution was three saw cuts,  through approximately two-thirds of the board, which allowed the board to be bent back into shape –  like so:


I drilled out the holes in the timber to accept No 12 screws and countersunk the holes (Fjord seem to have always used pan-headed screws even when hidden under wood plugs). I used Sikaflex to seal the heads of the deck/hull bolts and also around the shanks of the screws before refastening the boards.  I also took the opportunity the rout a small rebate on the underside to accept a bead of Sikaflex. (I’m sure I must have earned some shares in that company by now considering how much I’ve used in the last year).  Incidentally – that double screw-hole is down to Fjord,  not me!  It seems their first screw ended up directly on top of the chainplate bolt,  so the hole was capped and another one drilled just to the left 🙂


Here’s the timber plugged and masked ready for the 291 DC caulking sealant:





Here’s the repair I made at the aft end with a small graving piece inserted:




The end result is a significant improvement.  There are still some slight irregularities,  but the rubbing strake is once again easy on the eye …

There are still a million and one small jobs left to do,  but the water beckons – I reckon I have a couple of weeks work or so before we launch.  Yippee! 🙂

Posted in All the posts, General Improvements, Teak Deck Care | 6 Comments