Aux Engine Performance?

Channel Ribs · 06 April 2011, 12:03

If you have an auxiliary engine it would be great if you could post the horse power of the aux, size of boat and attainable speed.

Thanks in advance

bedajim · 06 April 2011, 12:13

6.5 M x 15 HP 2 ST = 7 Knts

Steering with main engine as rudder

Jim

Richard Selman · 06 April 2011, 13:30

7m 9.9 Hp main engine steering -> 5 knots

Richard

willk · 06 April 2011, 13:36

Out of interest - do you guys know what your speed would be if the main leg was out of the water? I'm not criticising, I'm just curious to know if there's much difference. I certainly would sacrifice a knot for a proper helm position too!

kwil · 06 April 2011, 14:20

6m Mariner 4 Sailpower 2 stroke 4.5 - 5 Knots. Main engine up or down makes very little difference seems to be compensated by the shift in weight of the helm from right in the stern using the tiller to moving forward to the wheel if using main leg to steer.

Keith

Richard Selman · 07 April 2011, 05:21

Makes little difference to my speed if the main engine is in the water. Also tried it in into F6 + waves and it only dropped to 4.5 knots.

Richard

Channel Ribs · 07 April 2011, 11:19

Thanks for the data so far, keep it coming

willk · 07 April 2011, 11:22

Thanks guys. Interesting

Grouse · 07 April 2011, 11:35

6.5M Rib 6Hp Mercury = 4.5knots.

BogMonster · 08 April 2011, 00:38

6hp Johnson 4 stroke on 5.8m Humber Destroyer about 4.5 knots
4hp Merc Sailmate 4 stroke with high thrust prop on Osprey Vipermax 5.8 about the same.

Likewise not much difference with leg up or down, less than 0.5kt anyway and much easier to steer!

Actual GPS speed generally fluctuates between about 3.5 and 6 knots over waves etc.

I find that about half throttle on the aux works best, full throttle gives very little more speed just more noise/vibration and higher fuel consumption.

Another useless bit of information is that with both the aux and the main engine running you can pretend you have twins and spin the boat on the spot

Nos4r2 · 08 April 2011, 01:14

2.2hp 'cause it's all that'll fit. 3 to 4 knots max depending on wind direction, steering with main engine.

monkeydiver · 08 April 2011, 07:37

8.5 Humber 18 hp tohatzu 10 knots
5.4 Avon sea rider 2 hp
Honda four 4 knots

willk · 08 April 2011, 13:42

Quote:

Originally Posted by BogMonster

Another useless bit of information is that with both the aux and the main engine running you can pretend you have twins and spin the boat on the spot

Yeah, Arnold Schwarzenegger and Danny DeVito kinda twins, maybe...

BogMonster · 08 April 2011, 23:14

Quote:

Originally Posted by willk

Yeah, Arnold Schwarzenegger and Danny DeVito kinda twins, maybe...

Obviously you do have "slightly" more revs on the aux than on the main engine