Proper RPM range

YYZRC

Do you have the Navionics app on your cell phone?  It will give you GPS speed and you can compare to your Raymarine.

Once I'm up on plane I fully retract the tabs and adjust the outdrive trim.  When I'm happy with speed/RPM after trimming the drives up I then use the tab(s) only to level the boat as/when needed.

I believe the fridges are the biggest draw.  You could for sure turn one off but the recovery time for a marine fridge is ages.  If the drinks get up to say 15 degrees in there, it would probably take 6 hours of fridge run-time to get the temp back down to 3-4 degrees.

There are little things you can do - switch all bulbs to LED, unplug the amp for the TV antenna (it is constantly powered).  I don't think your solar will do much as the fridges draw so much power; you need probably 400 watts of solar all day long to keep up to the battery discharge caused by the fridges. 

Did you get your generator figured out?  I usually run it in the morning to charge batteries + power coffee maker, toaster, water heater etc.  I'm not sure whether the engine or the generator+charger would charge the house batteries faster.  At least if you run the starboard motor you will get some 'free' hot water!

Pat310

@cnc before you shell out for a new gps download a free speedometer app for your phone. I never used one but seems to be tons of free ones on the Apple app store

CnC

Sorry @YYZRC yes generator was simply the breaker on its panel as someone here (possibly you?) suggested. Works great. That's what I've been doing (before and after having the boat pulled to fix the burst trim line) which feels a bit more natural to me through prior experience with my bassboat. But I'm definitely open to do whatever will work more efficiently. So the generator charges the house batteries as well? It seems fairly quiet but I do remember someone at the dock stating that others at the island docks kinda discourage generators running? Is this a rule that you know of or just a courteous thing not to do? How long do you run the Gen for?

CnC

Will do that @Pat310, thanks!

YYZRC

I'm sure someone like @Grahamu who runs a bit more conservatively in terms of RPMs can give better details on how to use the tabs efficiently.  The boating season in Ontario is short so I like to go fast!

The generator will power your 120v battery charger which will charge all the batteries on board; house and starting.

I anchor out in coves every weekend and there are always people running generators, especially in the morning.  I don't find it offensive, with the exception of the guy who shows up with a construction site genny on his platform that sounds like a chainsaw. 

When I get to a cove I always pick a spot on the outskirts.  If someone decides to nestle in on my starboard side, so be it, but they're getting my genny exhaust in the morning!  I run it for about half an hour in the morning, mainly to get hot water for a shower + coffee and fridges.  I also run it for an hour at night to run the AC to cool the cabin.  I do have a solar setup (3x100w panels) that helps with the fridges. Here’s a photo of my old setup on my 330. 

CnC

Awesome info @YYZRC Thanks so much
Cliff

Grahamu

Once on plane I give the drive trim a nudge with the button that operates both drive trims at the same time.
At anchor i normally run my genset for an hour at breakfast and the same at dinner time. I have a 4 - 6volt house bank and have not had a problem at anchor for 2 days. All my lights are LED but I make sure everyone understands they turn off items not being used. I cannot turn off my fridges as they  are on non-resettable 12 volt fuses on the breaker panel. I would like to change that sometime.

PickleRick

You can download a free app with speedometer for your phone(Waze also displays speed) so you can verify your GPS is accurate.

YYZRC

Grahamu said:

I cannot turn off my fridges as they  are on non-resettable 12 volt fuses on the breaker panel. I would like to change that sometime.

I did that on my 330

https://rinkerboats.vanillacommunities.com/discussion/comment/143031#Comment_143031

CnC

Was this difficult to do @YYZRC ? I'm guessing this kills the power to both fridges? Where can I purchase it, Amazon?

YYZRC

I got them from Grainger.ca. I think each fridge has a separate pop breaker that you can replace with these. Just make sure you get the correct amperage (match what you have now). You have to drill out the hole a bit with a step bit and drill holes for the mounting screws. 

On my Waeco fridges you can turn the thermostat dial to “off”. 

CnC

I'd like to tell you that I already thought of something so simple but I'd be lying. I'll check the cockpit fridge and turn it off if it has it. Probably won't admit it afterwards though if that's ok?

Grahamu

@YYZRC I looked at it over the winter but decided to put it off after looking behind the panel when it was out a few inches It was a problem just changing the panel lights.

Michael T

Yes, I probably am somewhat senile but to determine the proper RPM range for any boat I have ever owned I have consulted the proper RPM range of the engine in question and then propped it to run right to the maximum rated RPM at WOT. You can play around with drive gear ratios prop diameter, rake, number of blades etc. etc. but all that ever mattered to me was the proper rated RPM band and getting as close as possible to the maximum rated RPM at WOT. Period. If you under prop engines and aren't careful you can damage your engines due to over revving and no your rev limiter may or may not help you before the damage is done. If you over prop and run too low in the engine(s) RPM band range you will lug them and definitely damage them. My 2013 EC 310 with 350 Mags would hit 50 MPH on VV at WOT. My 2014 EC 360 with twin 502 Mags would hit 50 MPH on VV WOT. Those were properly propped boats. My Rinker 190 with a 390 HP 383 would hit 70MPH on a Gaffrig "tattletale" GPS Speedo at WOT within right at the top of its rated RPM band. It has always only been RPM at or close to WOT for me. If my engine's RPM band was rated at 4400-4800 I sure as h3ll aimed for 4800. By checking my RPM at WOT and ensuring they operated very near the top of their rated RPM (Mercury/Mercruiser engine tech shop advice btw) I ensured that if I had a bit of extra load more than when I tested my WOT I had a safety margin. IMO a boater who runs the engines too low in the rated RPM band at WOT has no insurance if they have extra "load" on board and is killing their engines by lugging them. I have posted before with stats from a friend who had a Rinker EC 350 with twin 350 Mags. These engines should never have been put in a boat that size, could barely get it on plane (very painful to watch) and were a constant source of trouble, gas guzzlers, underperformers and one eventually blew-up. Buy a boat with the correct sized engines and prop it to "tickle" its maximum RPM at WOT and your engine(s) will thank you. Get the biggest engine option for your sized boat and you won't have to have conversations about getting on plane or carrying a load. MPH is IMO irrelevant - prop/gear your boat to run very near the top of its RPM range at WOT under the load you most commonly use and forget it - unless you alter something in the equation significantly. If you do the run it at WOT again and see where the RPMs fall. 

CnC

Great info @Michael T . Your approach to WOT numbers with proper pitch props is how I did it in the past with smaller boats. No disrespect but going out and purchasing another boat (especially in this overpriced market?) that is properly powered isn't an option for me right now or most likely ever. Gotta make the best of what I've got has always been a crutch I've been blessed with. I appreciate your advice and will take this route as soon as I get all the correct numbers and then start trying props. 
Regards Cliff

LaRea

CnC said:

... So the generator charges the house batteries as well? It seems fairly quiet but I do remember someone at the dock stating that others at the island docks kinda discourage generators running? Is this a rule that you know of or just a courteous thing not to do? How long do you run the Gen for?

The generator will run all of the things that run on shore power.  You might pop a breaker if you run too many things at once (for example, air conditioner, water heater, cooktop and microwave all at the same time).

You can run the generator as long as you need it.  You can run it overnight if you are careful about ventilation and carbon monoxide detectors.  

If you want the generator to be reliable, run it at least twice a month for 15 minutes or more.  You can do this anywhere, including when the boat is in a slip at a marina.  But most marinas will not want you to run it for hours at a time inside the marina.  

When anchored with other boats tied up (rafted up) to yours, be courteous about running the generator.  There's no rule ... just be aware of how the noise and exhaust might affect others around you.  

Liberty44140

My previous 2006 342 with 350 MPI horizons and 22p props on bravo 3 drives maxed out at 4800 rpm and 41mph. I don’t think 48mph at 4200 is possible even with 24p props, especially at 4200 rpm. 

Unless of course the wind was blowing 48mph from behind you? 

PickleRick

You guys with 8 ton boats going 40 mph complaining about being under powered are funny.

My 220 hp 5 ton boat maxes out at about 22 with no crew and half a tank of fuel.  That's on a glass smooth lake with no wind. 

I filled up my boat in October back when diesel was 1.88 a gallon(112 gallons tank)

I just dropped below the full tank mark last weekend after some extended cruising.  My fv235 with a 4bbl 5.7 woukd use 10 to 12 gallons a weekend on a good weekend.

With a big block I don't think I could afford to go boating more than a couple weekends a year.

Black_Diamond

You can get a free app that will show your speed in mph.  Nice 2x checker.  

My old 342 with 350 MAG MPI and Hill Marine 20P 4x4’s would cruise at -4,000 rpm at 30mph or so. With tabs down on plane till low 20’s/ high teens mph. Those props solved everything. 😁. Rarely had to even trim the drives. 

davidbrooks

Oh and to your question of do we mess with the trim on the props while getting on plane?  No.  Just after you are on plane to find that sweet spot.  Getting up on plane they should be full down.  Now i will say that after switching over to the Hill 4 Blade props i don't do much to my outdrive trim.  Maybe bump it a little at 30mph and higher but not much at all.

Michael T

@PickleRick.....ain't that the truth, amigo. From memory: at cruise (30+mph) my 2014 EC 360 with twin 502 Mags set at perfect cruise attitude would drink about 24 GPH - sea level, 80 degree day with about 60% humidity - any higher for either value and the GPH went up. My brother-in-law joked on one cruise geez, man we are peeling-off 50 dollar bills here as we cruise! A fill-up (last time was 2016) of 91 marine fuel was about USD $800.00 ($1,100.00 Canadian). I filled-up about 20 times a year. To slip, maintain, store, gas, anchor (using generator) or visit other marinas on trips all added-up to ballpark US $25,000.00 a year. With a $300,000.00 investment it is not for the faint of heart! Do I regret a minute of it? H3ll NO - they were Rinkers!

PickleRick

I've never been into the top end of an efi big block but I have been into one with a carb.  If you open the top hat there are no jets, just little elves dumping 5 gallon jugs of gas directly into the intake.

Michael T

@PickleRick.......no - BIG elves dumping 10 gallon jugs. and they are hiding in the EFI too.

CnC

I downloaded a speedo app ( thanks @Black_Diamond ) and it does differ from the GPS making it 7mph faster. Its a Raymarine unit (not sure of the exact model offhand?) and I'm hoping that an update will fix this.  Thank you as well to @LaRea for the generator advice too. Never occurred to me run it to keep it working properly, I'll definitely do that from now on. Oh and by the way, Both fridges have dials that can turn them completely off if needed. I know this is probably small change to most here but we just did our first 2 nighter on an island dock (no power) and the batteries lasted pretty much 2 full days with both fridges running and using fresh water periodically as well as the electric toilet

LaRea

Okay, now I understand what you mean by "island dock" ... a stand-alone pier or floating dock with no power.  So here's the caution on generators:

If you are anchored with a single anchor, the bow stays pointed into the wind, and generator exhaust will flow safely away from the boat.  If you are tied to a pier, or if you have bow and stern anchors, the bow doesn't always point into the wind.  You might have exhaust drifting into the cabin, which increases the carbon monoxide (CO) hazard.  

So if you're on an island dock, yes -- be careful with the generator.  

YYZRC

@CnC did you replace your CO detectors? I buy the battery powered Kidde ones from Canadian Tire on sale for around $40. Always have two on board!

CnC

Yep, replaced it with that exact one as well. It definitely works because it has already gone off a couple times when I was doing some engine stuff on then dock at our marina so I know it works well and does its job

Boatruptcy

I have a 2004 342 with Merc 350 MPI and Bravo 3s and 3 blade 24p props.  Like @davidbrooks and Grahamu, I couldn't hit 48 mph unless I was going over a waterfall!  I cruise comfortably at 24-27 mph at 3300-3400 with trim tabs all the way up after getting on play, or down one notch depending on wind conditions.  I've never gone over 4000.

Michael T

@Boatruptcy (like the name btw) has any po ever had your engines to WOT - even just to bump them off the rev limiters. That is (imo the ONLY way) how you will find out if you are propped to avoid lugging or over revving - for your boat and your loading of it. I am reaching back down memory lane here I have owned 4 x 350 Magnums. I believe all were rated 4600-5000 RPM. The latest ones were twin 350 Magnums on B lll drives in my 2013 EC310 and they would both turn right up to their rated RPM at WOT. In fact I believe all of them would run to at least to their rated RPM at WOT...... IMO - as they should.

kordo

Yes, you can turn off the cockpit fridge by turning the temp control counter clockwise until it clicks.  At least that is how mine works.