Prop Question/ twin suzuki df200's on a 92 sailfish

[richmake]

This may seem like a simple question but I'm looking for some good input.
I've got twin DF200 Zukes with 3x16x20 counter rotating props.
The potential problem I have is we travel in an area with a great deal of crap in the water so eventually I'm going to spin a prop.
My current set up would cause damage to the lower end I can only assume so can anyone tell me if I should switch to a different prop/hub system.
Do these prop dimensions sound right for the boat/motor configuration?
Looking for suggestions
thanks in advance

 

[ocnslr]

Well, three blades and 16" diameter are standard on the Zukes with the higher ratio lower units.

The 20" diameter seems a bit high, so the best question is what RPMs can my make at WOT, with the engines trimmed up just short of ventilating?

When you do that test with a lightly-loaded boat, you should be right at the max RPM for those engines, which Suzuki gives as 6000RPM. If you can't make that, then you are "overpropped", i.e, too much pitch.

It is very important that you prop the boat to make that top RPM at WOT when lightly loaded, so you are still in the upper part of the RPM range when more heavily loaded. And so you are not lugging the engines throughout the RPM range.

Brian

 

[gw204]

My recommendation would be to look into a pair of Merc props (Mirage Plus or Enertia) that have the Flo-Torq removable hub system. They are designed to have the hub self destruct if you hit something in order to prevent damage to the props or gearcases.

I had 15-1/4 x 19 Mirage Plus wheels on my 225s and they were awesome. I bet that with the higher gear ratio of those Zukes you could spin the same.

 

[richmake]

Well..another crazy question.
I ran my boat yesterday strickly for sea trials and incountered something I never noticed before.
The boat seems to cruise at 4200rpm/25knots/17gallons per hour total....seems o.k.
The wierd thing is when I go full throttle...the gauges say 6800 and 7000rpm...
Is this possible or are the guages not working correctly.
shouldn't the top end be between 5000 and 6000rpm with the right props.
I'm not at all unhappy with my fuel economy/or ride....just curious