Hanse 470e - 55 hp or 75 hp Yanmar Engine?

[SFH]

Hi,

New member on this forum and in the process of surveying two HANSE 470e:

One with a Yanmar 55 hp and the other with a Yanmar 75 hp.

Apart from the engine they are almost identical in condition and outfit but the one with the 75 hp engine comes with a significantly higher price tag.

I am aware that HANSE included the 55 hp as standard but I am also aware that many have selected the optional 75 hp instead.

Would the 55 hp be sufficient - even if I want to add a second alternator?

Would I benefit significantly by going for the 75 hp version?

/Steen

[beneteau-500]

you want the 75 hp full stop and will need it if you wish to add extra alternator with the 55 you will be running it at max rpm all the time

[noelex 77]

No direct experience with the Hanse, but I have a similar length (but a bit heavier crusing boat)
When I re-engined a few years ago I faced the same decision between the two engines. Cost was not consideration. In the end I went for the 55hp mainly to avoid the complication of the turbo.

I am very glad I did. I would not pay exta for the larger engine.

[pbiJim]

1hp = 746watts. Power of a 50 amp 12 volt alternator = 50 x 12 = 600 watts, which is less than 1 hp, even after figuring in a little loss from the inefficiencies of the alternator system. A second alternator is not going to make a very big difference on a 50 hp motor. I think that the questions are - how fast do you want to be able to push the boat & are both motors reliable?

[Mystic38]

55hp is small for a vessel of that size.. particularly when you consider the requirement to motor into wind.. the Hanse, with its hull profile, will slap and stall easily if there is not enough HP to drive it through the waves.

@pbiJim, the common rule of thumb is a motor loses 1HP per 25 amp of alternator charging.. given anyone who adds a second alternator is usually adding one at 100A and up, this could be a significant loss..but only relevant if the OP is also trying to motor into severe chop...while his batteries are drained...ie..not really a factor.

[pbiJim]

Mystic, I'm not saying that you are wrong, but do you know where that rule of thumb comes from? I would like to research it more as it conflicts with other information that I have. I'd like to improve my understanding if possible.

Thanks,
Jim

[GordMay]

Greetings and welcome aboard the CF, Steen.


(Watts ÷ Volts) x Efficiency = Amps
(746 ÷ 14) x 0.5 = 26.6

One horsepower equals 746 watts.
Many alternator assemblies run at about 50% efficiency.

Hence: Approximate Rule of Thumb:
25 Amps of Alternator Output = ± 1 H.P. of Engine Power

➥ http://www.cruisersforum.com/forums/...tor-21496.html

[Boracay]

The other factors are your experience and how many crew and how experienced they are.

If you don't have a lot of experience then the bigger engine could keep you out of trouble and the same for the crew.

If you can sail the boat in difficult conditions then the smaller engine may be fine.

I put a 85 hp naturally aspirated John Deere into Boracay (15 tonne) and have only gone to full power on test runs. Mostly we would be using 20 to 45 hp at a guess. I've also been very conservative about what conditions we go out into.

My understanding is that the turbo engine needs to be worked rather harder than the naturally aspirated version and that there may be maintenance issues. Fuel consumption would also be higher.

[barnakiel]

At 12t I would opt for the bigger engine in a light hull like this. Except if only used to motor in/out of the marina.

b.

[FLLCatsailor]

I would stronly recommend going with the larger engine... You are going to burn less fuel, at the same cruising speed since you will be running at a much lower RPM... You'll also have more power for when you need it...

[Bash]

I have the 75hp Yanmar on a 46' boat with a high-capacity alternator, and wouldn't want to go smaller.

Had the 56hp Yanmar on my 41' boat and it was fine, but it only displaced 20,000 lbs and the 46' displaces 28,000 lbs.

[Tayzach]

I have the 75 hp engine on my Beneteau 473. It is a great engine. I would not want a smaller engine. The standard engine on my boat was a 63 hp.

[stevensuf]

The 55hp will be more than enough 99% of the time , there may be the very odd occasion you would call for more power, but hey the 75hp will be a turbo which will in the long run will give you more grief than the odd 1% of the time where you wish for more power, both should give you hull speed or very close to it (at a huge fuel disadvantage vs 5-6kn).

Most cruisers motor in the 5-6kn range in a boat this size on longer journeys, to conserve fuel and extend range, in calmer conditions you will consume 2-3 l per hour at this speed equating to 8-12hp in use! So in average motoring conditions you will be using only 20-25% of the capacity of the smaller 55hp engine. Puts it perspective doesn't it?

[Cheechako]

My 47 Passport had 80 HP and it seemed about right. Heavy boat though. My HC38 had 30 HP and was severely underpowered.

[tobo]

We own a Hanse 470 equipped with the 75 HP version (Yanmar) and a Flexofold propeller (3 blades) with saildrive. It runs since 6 years in the Med and we only once had a bigger problem as the propeller sealing was leaking due to fishing lines or bits of plastic bags around we didn't realize quickly enough. The gearbox/clutch had to be exchanged (in water!) and that was it. The fuel consumption is between 3.5-4.5 l/h and we run it at 2200 rpm. Keep an eye on the oil level and consistency in the gearbox every month and every 2-3 days of the engine. The same with the water level and you will never have problems with a Yanmar as it is a pretty basic type of diesel without a lot of electronics . Nowadays Hanse switched to Volvo - I think they need more attention and have more electronics.