rpm and correcting

[rick1954]

I have a question about my E26 351ci. I just got back from a short trip to a BBQ, on the way down river, going out with the tide. I was following other boats from my marina. We were moving along about 1800rpm. At this rpm I was constantly correcting course, no, I was back about 100 yards from the other boats. On my way back up river, again going with the tide, running by my self, at 2100 rpm I did not have to have my hands on the helm and did not have to correct corse. What rpm should you be cruising at, is 2100 ok or should I be higher, some input please. I read that article about mushing and stuff that did not help me one bit.

[Stripermann2]

Well, for one, you always have more control against a tide than with a tide. A bit faster speed as on your return trip, would also indicate a better handling boat. Everyone cruises at different speeds dependant on their local conditions, sea, wind, tide, etc.

Current is different than tide. If the tide was moving fast on it's way out, and you are traveling with it, the boat may handle differently as opposed to coming through a narrow channel with a fast current.

You just need to find that sweet spot where you are comfortable with speed and control. Don't overlook simple ballast conditions too. I.E.- When my holding tank, which is up under the v-birth if pretty full, it can make for sea-keeping hell at certain speeds until I pump out. Keep mental notes as to what loads you have on the boat when you go out at different times.

[MattSC]

Striperman has pretty much hit the nail on the head. Alot of it depends on how fast the current is running, also don't forget to factor in the wind. Remember, the rudder on an F-26 is pretty small and the prop is only 14" in diameter. If you aren't running with your stern directly in the current, this can also push you off course and cause you to have to correct. When you alter course to correct, make sure you give the rudder a chance to react or you could be constantly "chasing" the boat to run a steady course. As for picking best speed to run, every boat is different. It all boils down to where you feel the most comfortable running the boat while maintaining control. Certain parts of my trip down the river (last 2.5 miles) is no wake, the current can run up to 3knots or so and I can't run much more than 1000 rpm without leaving a wake. You have to think ahead of the boat, if that makes sense

[rick1954]

When I was running with the tide down river, I could not go to much more than 1800 rpm otherwise I would start to approach the boats that were in front of me. The Hudson river is wide where I was and not so much current. However, she corrects with very little rudder movement, I do know what you mean about over correcting, my first mate drives me nuts when she has to take the helm, she thinks she is tacking or something. The boat runs true at 2100 rpm all the way up to WOT, well I have had her up to 3800 rpm briefly and did not push past that. This is true for both directions tide no tide.
Is 2100 ok to run at , some one said that you should run the engin to the recommenced rpm, but this information I cant find. I have all the manuals and this information is not present.
I cant go to much over idle without making a wake, which is around 6 to 800 rpm. I think that if I were to stand on the stern and blow thru a straw the boat would move.
Thank you for your help.

[MattSC]

Rick,
As far as runnning the engine to the recommended rpm, I believe what you are referring to has to do with your maximum recomended rpm. For example, my engine has a recomended rpm of 4800-5200. If you are below that, say 4400 rpm maximum, then you have your boat over propped and the engine is "lugging" or working too hard which can lead to premature failure. My original engine was an LM318 chrysler which had a recomended rpm of 4000 at WOT. I'm not exactly sure what the rpm band is on a ford engine, I'll see if I can research it a bit for you.
As for a cruising speed, If you feel the most comfortable at 2100 rpm, you should be fine, it's not going to hurt anything. I usually run anywhere from 2600 to 3100 rpm, but it's a different engine with a different power band. If I'm not in a hurry to get anywhere and just putting around I'll cruise around 1600 or so.
Matt

[rick1954]

Thank you, that is what I was looking for. I think the WOT on this engin is around 4800rpm but not sure, I had her up to around 3800 with throttle to go. At 3800 this boat was moving, don’t need to go faster. Going along at 2100 was nice.

[lakeguy72]

The 351 cu in Ford 233/255 HP has a range of 3800-4200 per my Mercury owner's manual. I don't think I'd change props if you are at 3800.