Duo-prop size - Sealine S34

[QBhoy]

I shouldn’t likely offer comment here…but just a couple of comments, from what I do know around these engines and the s34, but with different engine installations…

so firstly, I’d say that the kad32…although A fairly coarse engine…is in my opinion, most likely underrated, in terms of actual Hp. Seems to me, to be a very potent and powerful engine, for her claimed 170hp. Especially in your average installation and mated To a 290dp and powering the usual boat like a Sealine s23/25.
Anyway…despite that…although twin set ups of the above in a boat like yours…would be considered the lowest power option when new…I’d say they would still do pretty well…and to be really fair…27/28 knots from this set up, should be considered pretty bloody amazing, in real world terms. I might also suggest that if you are achieving this speed verified by gps and with A4 props…I’d say with some confidence, that your tachometers are a little off the mark.
Anyway…as little and as rough around the edges, as these wee engines may appear, in comparison to the other options, like the Cummins and VP 6 cylinders…they seem to so just fine, for what they are…as long as there is adequate sound insulation around the machinery hatch.
Regardless…I think you’re doing just fine as you are (even if the rpms might be a little off)…and very envious of your boat too. All the best !

 

[Greg2]

Tachos were a little out the real issue turned out to be fuel filters with insufficient flow rate. We only kept the boat less than two years but loved it and the engines - your comments about them are spot on!

 

[Momac]

so firstly, I’d say that the kad32…although A fairly coarse engine…is in my opinion, most likely underrated, in terms of actual Hp. Seems to me, to be a very potent and powerful engine, for her claimed 170hp.

Certainly the 6 cylinder engines are smoother at low rpm , but that is to be expected.
On the other hand I always feel you would never know there are only 4 cylinders in a kad32 when up to speed.

The idea of the kad32 being under rated at 170hp may be due to the fact that the kad32 is lighter weight than the ad41. For this reason , in the same or comparable boat and the weight factor x 2 engines , the advantage of the Ad41 over the kad32 is perhaps not so great as might be expected. However in a S34 the AD41 almost certainly wins the day in overall performance. But not a lot in it.

Extra engine bay space with kad32's in a boat like the S34 which is designed to accept 6 cylinder engines is a benefit.

I must confess to being a fan of the kad32 having only owned two boats , both with kad32's. But I would be completely happy with ad41' or kad43's as I believe this little group of engines to be a good solution for boats .

 

[QBhoy]

Certainly the 6 cylinder engines are smoother at low rpm , but that is to be expected.
On the other hand I always feel you would never know there are only 4 cylinders in a kad32 when up to speed.

The idea of the kad32 being under rated at 170hp may be due to the fact that the kad32 is lighter weight than the ad41. For this reason , in the same or comparable boat and the weight factor x 2 engines , the advantage of the Ad41 over the kad32 is perhaps not so great as might be expected. However in a S34 the AD41 almost certainly wins the day in overall performance. But not a lot in it.

Extra engine bay space with kad32's in a boat like the S34 which is designed to accept 6 cylinder engines is a benefit.

I must confess to being a fan of the kad32 having only owned two boats , both with kad32's. But I would be completely happy with ad41' or kad43's as I believe this little group of engines to be a good solution for boats .

Agree. Good points.