Category Archives: Engine room

Starter motor

Taking down the sails and getting ready to enter harbour only to find that something (discharged batteries?) prevents the starter motor from turning over at the usual pace is a somewhat tiring experience. In our case, the problem wasn’t discharged batteries but one of the brushes in the starter motor that had gotten stuck in its holder. Luckily, we had an extra brush holder complete with brushes on board; it took a bit more than an hour to change and the holder with brushes cost about USD 15.

On old holder (right), one brush was stuck.
On Anna, removing the starter motor is a 10 minute job due to easy access.

New heater #2, installation

After finding out that the heater brand “Planar”, manufactured in Russia, are being sold at less than half the price of similar German heaters, I decided to replace our old Webasto. I found a complete kit of the model 44D-12-GP-TM available from , including a spare glow plug and freight, for only SEK 6,000. Delivery was prompt and trouble-free.

Installation was straight forward, except;
1. I replaced first three meters of heating duct (was 80mm, now 100mm). All the heating ducts have previously been insulated as it improves heating markedly.
2. Old heater had a pump lifting from the main fuel tank. New heater has a dedicated fuel tank (7 litres) – although this can be supplied from the main tank with a separate lift pump in the future. I decided for this solution so as to ensure clean fuel for the heater.
3. Connections for combustion air and exhaust are 26 and 24mm respectively, significantly smaller than the old heater, meaning that new reductions have to be made.

The heater started on the second attempt (after the fuel line had been primed…) and worked as expected.


The Planar is rougly the same size as the old Webasto, so coudl be fitted in the same location. Exhaust connection is still temporary, awaiting welding of 80-24 mm reduction. Some tidying up still left to be done…


Although manufactured in Russia, the heater is sold by Autoterm in the Czech Republic and carries a CE marking.



After installation, I was happy to confirm that the Planar actually consumed slightly less electricity than stated in the data sheet.

New curtains


Another great example of the principle that one should never try to estimate how much time a job on a boat will take, since it simply will a) decrease the probability that you will do it and b) be wrong by a factor of about 3 (the job will always take 3 times as much time as your estimate, no matter what your estimate is). Better to just start working; then you will at least save time on planning…

On the HR41, there are 32 curtains (16 portlights), assuming you do not put curtains on the portlight in the cockpit locker. We decided to go for a fabric which matches the gelcoat and also lets some light thru (as opposed to the old/original curtains which were dark blue).


Old curtains.


New curtains; 32 pieces, Thankfully, tthe sewing is very simple.


The fabric prevents people outside from looking in, but still lets quite a lot of light in.

Engine sizing

The guys who own Maringret, another HR41, have put up a calculation on their blog at of how they sized their new engine. It’s a great step-by-step calculation which shows an application of the chapter “Engine selection and installation” in Nigel Calder’s book Marine diesel engines (and if that doesn’t interest you, you should check out their collection of links) . Here’s how our calculations (leading us to aim for a 40hp engine) compare with those of Maringret (leading them to target 60+ hp).

Boat                                                 Maringret        Anna #1        Anna #2          Anna #3
LWL, m (ft)                                     10.4 (34.1)          10.4 (34.1)     10.4 (34.1)       10.4 (34.1)
Bow wave velocity, knots             5.84                     5.84               5.84                  5.84
SLR (theoretical)                            1.34                      1.34               1.34                 1.34
Hull speed (theor.)                        7.83                      7.83               7.83                 7.83
Target max speed, knots             ??                           6.5                 7                      7.83
Displacement, tons (long tons)   18 (18.29)            14 (14.2)       14 (14.2)         14 (14.2)
Water resistance, lbs / long ton   55                        20                  28                    55
Total resistance, lbs                        1006                  284                 398                 781
Effective hp                                       23.6                   5.5                   8.4                 18.3
Propeller efficiency, %                     50                      65                    65                  65
Required hp                                      47.2                   8.5                   13                  28.1
Adverse allowance, %                      33                      33                    33                  33
Target hp                                           63                      11                    17                   37

The calculations are a great illustration of how the energy required increases exponentially as you try to push the boat faster than the bow wave. And that most boat issues are a matter of compromise and a consequence of intended purpose.

On the Volvo Penta web page, there’s a nice little engine configurator to identify the recommended engine size depending on length of waterline, displacement and required top speed;

Replace heat exchanger

During the three seasons since new, the heat exchanger has developed small corrosion pits at the front cap for the tube stack. The tube stack itself and the inside of the heat exchanger were fine. To their credit, Vetus sent a complete new heat exchanger without any discussion whatsoever. It looks slightly different from the original one.
The o-rings for the end caps are 61×2.5. The end caps of the new heat exchanger are brass instead of the original plastic.

As with most new engines, it does not have any sacrificial zincs. All the manufacturers claim that the alloy shall withstand corrosion. Well, I’ve fitted zincs anyway…


Old heat exchanger


New heat exchanger


New. Aft end cap.


New. Fwd end cap.

Old. Corrosion of housing at o-ring.

Old. Corrosion of housing at o-ring.

Engine experience

After doing 3000 nm during 3 months, whereof about half under engine, our experience shows;

  • motoring consumes, on average, 0.4 liter per nm (equal to 2.6 liter per hour)
  • motoring against a headwind of 8-10 m/s and 1.5m waves at 2200 rpm gives a speed of about 5 knots
  • motoring against a headwind of 14-16 m/s and 2-2.5 m waves at about 2500 rpm gives a speed of 3.5-4 knots

Taking into view actual motoring performance as stated above, we are happy with the engine fitted. If one also considers fuel consumption, easy access to service points, lower weight and also lesser drag when sailing compared to the bigger propeller a larger engine would require, we consider ourselves lucky that we did not fit a bigger engine. Obviously, this is also what the Hallberg-Rassy people figured out, since the original engine produced 45 bhp.

Test of new engine

To our great relief, the engine started on the first try and ran perfectly. We did a one-hour test-run (keeping below 2000 rp, in compliance with the manual’s instructions for breaking in) and were very pleased with the very low noise and vibration level.

The speed achieved with the Vetus M4.17 in the HR41 (42 bhp, 12 tons) was almost identical to the speed achieved with the Volvo D2-40 in the HR35 Rasmus (38 bhp, 7 tons). 5 knots at 1500 rpm, 5.5 knots at 1700 rpm and 6.3 knots at 2000 rpm.

Engine room, complete

The engine replacement is now complete. In total it cost double the purchase price of the new engine, which included not only the new engine and transmission but also the work and material of the following;

  • installed new sound proofing of engine room
  • replaced all hoses
  • replaced entire exhaust system
  • replaced prop shaft, cutlass bearing and propeller
  • installed Bullflex between transmission and prop shaft
  • installed instrument panel with analogue gauges
  • installed engine control (single handle Teleflex)
  • replaced electrical diaphragm bilge pump
  • replaced water pressure pump
  • installed extra fuel filter (Racor)
  • installed sea water strainer
  • cleaned and painted engine room

new engine sThe new Vetus M4.17 is considerably smaller than the old Volvo MD21, making all service points much easier to reach.








Many thanks to Jonas at for the excellent job; done at the agreed price and finished on time!

Rebuild Webasto heater

The guy who sold us the boat had told us that the heater made some noise and probably needed a new bearing. Since the heater had to be taken out of the engine room when replacing the engine, we took the opportunity to rebuild it; disassembly, replace two bearings (one indeed proved to be damaged), general cleaning, replace grease in fuel pump and paint.

webasto-lagerwebasto helbild b