what prop for low speed trawling.

[jurgenscraft]

I have a 21 foot cabin boat powered by a 225hp Evenrude motor which has a
omc 14 1/4 x 21 pitch prop, this combination runs very well, planes well and runs true to the manufacturers rpm range,but, when I have reached the fishing area I reduce throttle and trawl at 2000 to 2500 rpm at this rpm I am travelling at the trawling speed required.I was wondering if I should not try a prop with a lower pitch to bing up the rpm by 750 rpm or so as to keep the plugs clean and the motor nearer its power band, some days we trawl for 4 hours or longer at a time,will trawling at reduced rpm have any detrimentel effect on my motor,or am I just worrying about nothing.
king regards William Wright.

 

[Silvertip]

Re: what prop for low speed trawling.

2000 - 2500 RPM should not bother the motor a bit since it is properly set up now. By going to a lower pitch you would obviously raise the rpm and get a little better hole shot, but you would lose significant top end and would have to monitor RPM very closely (and throttle back) to avoid over reving at cruise. A 750 RPM increase would mean you need to decrease pitch by 3 - 4 inches (dropping to a 17 - 18 inch pitch). Since at WOT you are in the proper rpm range, with the lower pitched prop WOT would mean you would over rev by 750 RPM. If you are not having any performance issues (plug fouling, etc) now, leave things as they are. At 2000 - 2500 you are running at displacement speed so fuel economy should not be an issue. If you still feel you need to raise the revs a bit, the most I would change would be to a 19P. If you are at or very near the top of the rev band at WOT, 400 RPM would not harm anything as long as it didn't continually hit the rev limiter.

 

[Texasmark]

Re: what prop for low speed trawling.

I'd leave it alone as you have all your ducks lined up. 2000-2500 rpm's is not like running 600 rpm's for extended periods.

If you changed props to satisfy your trolling your mpg and performance to and from the fishing site would be unacceptibly low and slow.

I have proven (to myself) that an engine tilted up, as Merc did (maybe still does) years ago when they made the slant fishing engines, that fuel puddles in the cylinders if the cylinder is not tilted up when trolling. So as an added measure, just trim your engine up so that the rear is a little higher than the front to help in eliminating any puddling which would aid you in your quest for not loading up your engine while trolling.

Use syn oil (Pennzoil has it) and add Sea Foam to the fuel. Both will reduce smoke and keep your engine from loading up.....I have also proven that to myself......I don't care what others say about it.

Mark

 

[EricR]

Re: what prop for low speed trawling.

Are you talking about trawling, which is to drag a net along the bottom such as a shrimp boat, or trolling,which is to proceed slowly while pulling fishing lines in the water? Big difference, as trawling would put quite a low RPM load on the engine and need a low pitch work boat type prop.

 

[Bondo]

Re: what prop for low speed trawling.

Ayuh,.......

If you're trying to get your Trolling speed down,+ the RPMs up,.......

Add an over sized set of Trim Tabs,+ a couple Sea Anchors.........

Run out to the Fishing Grounds,+ then put the Tabs, All Down,+ tie off the Sea Anchors to the forward cleats.......
If that doesn't work, get Bigger Sea Anchors(Drift Socks).......

 

[Hashi]

Re: what prop for low speed trawling.

Are you trolling or trawling?

If your trolling, I'd look into a second motor. Don't want to put that much stress on your primary engine.

If your trawling with nets, then I'd seek professional trawling captain's advice.

 

[jurgenscraft]

Re: what prop for low speed trawling.

sorry about the long delay regarding the trawling / trolling I am trolling in the fishing areas some times the motor runs at 1750 rpm.
Regards William

 

[HighTrim]

Re: what prop for low speed trawling.

If you do find you are having plug issues, gapping them an extra .005 will help if you are doing extended trolling.

 

[rndn]

Re: what prop for low speed trawling.

A little off base, but what are you trolling for that requires you to run 2000rpms?

 

[Bondo]

Re: what prop for low speed trawling.

A little off base, but what are you trolling for that requires you to run 2000rpms?

Ayuh,.........

Or,......
What motor do you have that won't idle lower than 1750rpms,..??..