Will a 15 X 19 instead of a 16 X 19 work?

[Old Blue]

I would like to try a 16 X 19 prop on Old Blue but all I can find are 15 X 19 props. Does anyone know how this would work? Can anyone offer a guess? Any insight would be appreciated.

Thanks in advance.
Brian on Old Blue

[NoSlack]

I have heard that 1" in diameter = 2" in pitch on the top end.
If you are running a 16" X17" now and go to a 15" X 19", you may end up in the same place.

I'll give ya a 16 X 17 if you wan't one to get re-pitched.

Mike

[Old Blue]

Well, I put her in the harbor with a 15 X 19 prop that had some cupping to it from Propellers of San Diego. I really liked that prop, it had a lot more blade area than my old 16 X 17. Heck the boat ran a knot faster at idle and had way more oomph backing off the trailer. I was so mesmerized with the change in handling that I ran through all my rpms without remembering to fill the bait tank. It was cool running 25 knots at 3500 rpm full throttle, I was thinking Ya baby this ones for me! Then I remembered that I better fill the bait tank and start taking down some numbers.

2600 14.5 kt
2800 17.3 kt ~ 170 degrees
3000 20.0 kt ~ 179
3200 22.5 kt ~ 190
3400 24.9 kt full throttle and warming up fast

Headed back to the ramp trying to think up ways I could add more cooling capacity.

Put her back on the trailer and switched over to Mikes old 16 X 17. I had thought that mike and I were running the same prop back when he had his 280 single prop. Fact of the matter is, mine was not an "elephant ear" but must have been a regular prop because it looked like Mikes had about 30% more blade area.

Headed back out and ran her again. Apparently the tide had started to flow.

2600 14.4 kt ~162 degrees outbound
2800 14.7 kt ~168 inbound 16.0 kt outbound
3000 17.0 kt inbound 18.7 kt outbound
3200 19.6 kt ~178 inbuond 20.7 kt outbound
3400 21.8 kt ~185 inbound
3600 23.6 kt full throttle inbound 24.8 kt outbound

All numbers were taken with full fuel tk and full bait tank and just myself on board. I figure this leaves me about 350 lbs shy of what I would be heading out for tuna since I would have a buddy, 100 lbs of ice and some fishing gear. Looks like the 16 X 17 elephant ear is the right prop.

My regular prop (16 X 17 with smaller blades) gave me 20 kt at 3400 rpm ~175 degrees with a full throttle of 3700 rpm.

When its all said and done I picked up about 5 knots on my cruising speed by replacing my 130 HP AQD40A with the 165 HP AQAD40B. Anybody got a good looking AD41 they wanna donate to a good cause?

Brian on Old Blue out.

[NoSlack]

Lookin good Brian.

Mike

[Moo Fish]

Did you say 41a's. I have a herd of them. But all project engines, one way or another. Happy to give you a tour.

RT

[Old Blue]

even if I was asking for it! Have two electronics installs to do, a coolant issue (might have to talk to Scott re his old heat exchanger) and can't seem to get that JRC 1800 radar out of my head!!!

I need another guy to live my life while I take care of a few things.

Brian on Old Blue out.