Having more than one prop

[-JR-]

Hopefully someone has the same boat and can tell me what works best as I was thinking of getting a few differnt sizes

1984 Baylinner 18 foot volvo QA125a with a 270 leg

Boat came with a 14x19 works good about -30 mph at 4500rpm / 2 mph at 1000rpm

I tried a 15x15 did not like that - 20 mph at 4500 and 3 mph at 1000 rpm
to fast for trolling for fishing , engine also over heated while at 4500rpm

Was thinking of trying a 14x 21 on the boat but how will it do at low speed and high speed.

I only use the boat for fishing .

Heard today you should never drive your boat slow below 3500 rpm as engine and leg willl not get lubed or cooled enough is ths true ?
Should i not be using it for trolling ?
As i have for 8 years now .

Any info is wellcome.

 

[hwsiii]

Re: Having more than one prop

JR, we will try to help you as much as we can, but there is certain information that is needed in order to help you. The following form has all of the information that is needed to help you with your problems finding the right prop. If you do not know all of the information that is asked for on the form please give us the most information you have available, and especially all the information that is in RED as I have a program I designed to find the right prop for any planning hull boat that needs this information. It requires time to find all this information when we have to look for it and in my defense I expect you to be willing to expend as much effort in finding the right prop as I do. We hope to be able to help you get the exact prop you need for your particular uses, and this information is required to do that.


Iboats Boat and Motor Info

H

 

[steelespike]

Re: Having more than one prop

Your speed seems low with the 19 I think it should be closer to 40.
How are you measuring speed?Normally the 19 would troll faster than a 15.
Normally the 15 would rev much higher than the 19.Are you holding the rpm at 4,500 with both props or are you letting it develope full rpm? If you had an over heat you probably have a cooling issue developing and its not related to the prop size.
I'm no I/O expert but the only draw back I see to trolling is the many hours of wear your putting on the relatively complicated drive system.universals,various bellows,I believe 2 water pumps.I think most use a kicker motor but like I said I'm on the outside of I/O operation.