[Barry]

Hi,
My Z275 has a Volvo 7.4Gi with a DP Outdrive and a F5 stainless prop set-up.

With this set-up the engine pulls 4600rpm and tops out at 46mph.

I am considering purchasing an F9 duo-prop in order to increase top speed.

I would welcome any thought that you might have on whether this will be effective.

Many thanks,
Barry

[Dredd]

I'm not familiar with the Volvo Penta models (so I'm not sure what Merc model the DP compares to) but typically people don't install dual prop drives to gain top speed. The advantage of dual props is hole-shot and dock/low speed maneuverability. In many cases you actually sacrifice top speed for the other benefits.