2009 searay 350da vs2008 monteray 350, mph gph cruisng style

[keokie]

ET,

Something is amiss. First, yes outdrives should give you considerably better efficiency than inboards in your boat. Inboards have great advantages (I am not trying to start a war, just trying to help the OP), but speed and efficiency go to the outdrives even in your size boat.

We do need to know a few things...

What props are you running?
What gears are in the drives?
What is your WOT speed?
What is the toe in on your drives when they are straight?
Are your celery sticks set for maximum negative trim?

Generally, leave the drives trimmed in all the way and raise tabs first. If you can raise the tabs all the way and stay on plane, try raising the drives a very little at a time.

If you raise the tabs and lose speed, you may need to add a little rpm. If you are cleanly on plane, you should not lose speed by raising tabs.

Answer the above questions for me, and I can provide valuable input. I have a bit of experience running outdrives in boats in your size range.

Very cute kid!

 

[JimT]

The OP has said he is running with the tabs 70% down at 3400 rpm. I suspect that if he pulls them all the way up it will solve his problems. Trim the drives up a couple of bumps and all will be good.

 

[Ethan's Tank]

The OP has said he is running with the tabs 70% down at 3400 rpm. I suspect that if he pulls them all the way up it will solve his problems. Trim the drives up a couple of bumps and all will be good.

I'm telling you, the mph drops if I run the tabs with it any lower. Bow rises and I lose a few mph

 

[Ethan's Tank]

I'm going to see if I can video all this and upload to YouTube for proof

 

[Ethan's Tank]

ET,

Something is amiss. First, yes outdrives should give you considerably better efficiency than inboards in your boat. Inboards have great advantages (I am not trying to start a war, just trying to help the OP), but speed and efficiency go to the outdrives even in your size boat.

We do need to know a few things...

What props are you running?
What gears are in the drives?
What is your WOT speed?
What is the toe in on your drives when they are straight?
Are your celery sticks set for maximum negative trim?

Generally, leave the drives trimmed in all the way and raise tabs first. If you can raise the tabs all the way and stay on plane, try raising the drives a very little at a time.

If you raise the tabs and lose speed, you may need to add a little rpm. If you are cleanly on plane, you should not lose speed by raising tabs.

Answer the above questions for me, and I can provide valuable input. I have a bit of experience running outdrives in boats in your size range.

Very cute kid!

Thanks Keokie, don't know these number off top my head nor if I have them all. I'll see what I can get and post them up

 

[Ethan's Tank]

Ethan

Your speed sounds off, but your MPG sounds fairly accurate.

My 2010 350 is a bit lighter than yours, but I have twin 8.1 HO's, but V drives vs outdrives.
I cruise about 3400-3500. I get about 25-27mph. My mph creeps up the longer I cruise as my fuel tanks empty. I average about .7 MPG. These engines are definitely not fuel efficient.

Also, when comparing to other boats look at total weight, not just dry weight. Do you cruise with full water, fuel etc? Also, when was the last time your boat was out of the water and the bottom was cleaned? I know the river creates a slime and I practically get a beard on my bottom. (Even with paint). This will impact your performance.

I obviously can't trim my props, but I do use my tabs to get up on plane if I have a full boat and then I put them back up once on plane.

Also, comparing current models with newer 8.2's to our boats doesn't work. As I understand it, the newer 8.2's are more efficient.

Hey Ryan,

Yes your 2010 would be like my year series 330. I cruise most of the time with.a small family; wife young son, small dog and large dog..if I were to guess, we are about 500lbs total. Fuel is rarely over half, water tanks full, grey normally about 25%, some food, lots of beer and water.

It was out of the water 3 weeks ago, it didn't have any barnacles or growth on it, but bottom was last clean this past April.

 

[Jeremygavin]

I have a 340 with same motors and drives. I am running 28" hill marine 4 blade props and my cruise is best at 3400 Rpms and that gets me about 30-31 mph burning 30-33 gosh so that is around .97-1 mph. I have the celery sticks flipped for maximum negative trim. To get on plane I have out drives trimmed all the way down and tabs all the way up. The only time I need tabs it to level the boat or maintain plane at slower speeds. Once on plane and at Soren I trim the drives up a few "bumps" of the switches, too much and I loose speed. With a few bumps I don't gain any speed but I gain a some Rpms which increases efficiency.
My dry weight is about 1200lb lighter than yours and I have more length but also a little more beam so to my it sounds like your numbers are a bit low. I can't imagine 1200 lb would make that much of a difference. When I have just my wife and I on board with little fuel and water I can get a little better numbers but when I am fully loaded water, fuel, 8 people I can still get 28mph and only I am burning 32-33 gph. That is still .87 mpg.

 

[Ethan's Tank]

I have a 340 with same motors and drives. I am running 28" hill marine 4 blade props and my cruise is best at 3400 Rpms and that gets me about 30-31 mph burning 30-33 gosh so that is around .97-1 mph. I have the celery sticks flipped for maximum negative trim. To get on plane I have out drives trimmed all the way down and tabs all the way up. The only time I need tabs it to level the boat or maintain plane at slower speeds. Once on plane and at Soren I trim the drives up a few "bumps" of the switches, too much and I loose speed. With a few bumps I don't gain any speed but I gain a some Rpms which increases efficiency.
My dry weight is about 1200lb lighter than yours and I have more length but also a little more beam so to my it sounds like your numbers are a bit low. I can't imagine 1200 lb would make that much of a difference. When I have just my wife and I on board with little fuel and water I can get a little better numbers but when I am fully loaded water, fuel, 8 people I can still get 28mph and only I am burning 32-33 gph. That is still .87 mpg.

Curious but what is your length and beam?

My 350 is 39.6' and 12' beam
I'm going out today, so I'll try it how you do it.

 

[Ethan's Tank]

Does anyone run theirs on cruise control, I'm wondering if this messing with my numbers then.
I set it to 3400 Rpm and let it ride

 

[Zorba]

It should make no difference. That would be just like syncing the tacs.

Also unless you have an aftermarket swim platform you are at 37' 6" loa.

Sent from my iPhone using Tapatalk

 

[Ethan's Tank]

It should make no difference. That would be just like syncing the tacs.

Also unless you have an aftermarket swim platform you are at 37' 6" loa.

Sent from my iPhone using Tapatalk

That looks like a 2010, mine is 2009. It came with a extended platform, Loa is 39'6"

 

[WDCboater]

Hey Ryan,

Yes your 2010 would be like my year series 330. I cruise most of the time with.a small family; wife young son, small dog and large dog..if I were to guess, we are about 500lbs total. Fuel is rarely over half, water tanks full, grey normally about 25%, some food, lots of beer and water.

It was out of the water 3 weeks ago, it didn't have any barnacles or growth on it, but bottom was last clean this past April.

Barnacles are not the issue on the northern half of the Potomac because it's fresh water. The big issue is river slime. Even a thin slime coating will cause you to lose a couple MPH, but it sounds like you're having more loss than that.

Hope me you can figure out the issue.

 

[Ethan's Tank]

Barnacles are not the issue on the northern half of the Potomac because it's fresh water. The big issue is river slime. Even a thin slime coating will cause you to lose a couple MPH, but it sounds like you're having more loss than that.

Hope me you can figure out the issue.

Today when I took my boat out to test everybody's techniques ie tab trims at 0 and power trims at short burst or trim down, etc. I noticed a drop in Rpms or a jump in Rpms with different combinations, but I always saw in drops in speed. I watched where my wake was created under the boat and how my rooster tail trailed. At the best combination, I set trim back to zero, lowered the tabs to about 50% and set cruise control to 3450, my speed raised to a steady 27 mph, burning @ .08 mph.

 

[Ethan's Tank]

Barnacles are not the issue on the northern half of the Potomac because it's fresh water. The big issue is river slime. Even a thin slime coating will cause you to lose a couple MPH, but it sounds like you're having more loss than that.

Hope me you can figure out the issue.

Ill have to figure out a way to clean the bottom, but at aquia, we are kind of mid-Potomac. Some of the boat here have a crust of barnacles on their out drives and bottom. It's saltier now with all the Damn crab pots in the channel, i'm able to catch a dozen crabs off my Marina docks

 

[WDCboater]

Today when I took my boat out to test everybody's techniques ie tab trims at 0 and power trims at short burst or trim down, etc. I noticed a drop in Rpms or a jump in Rpms with different combinations, but I always saw in drops in speed. I watched where my wake was created under the boat and how my rooster tail trailed. At the best combination, I set trim back to zero, lowered the tabs to about 50% and set cruise control to 3450, my speed raised to a steady 27 mph, burning @ .08 mph.

This sounds about right. Your cruise/burn is similar to mine. Two seasons ago we did a four day trip around the bay and I asked some of the techs at PWM if my fuel burn was normal. They said yes. I also don't get the range that some tests show.

One other thing, speaking of range, to keep in mind is running your generator. It cuts into total range and will suck about a gallon and hour. On my boat they hooked the generator up to the smaller tank!! One is 110 the other is 119.

Once or twice a season when we're anchored I'll grab a sponge and swim around the boat and clean the bottom. It's messy. I keep a snorkel on board. Don't use anything abrasive or it can peel your bottom paint.

 

[WDCboater]

Ill have to figure out a way to clean the bottom, but at aquia, we are kind of mid-Potomac. Some of the boat here have a crust of barnacles on their out drives and bottom. It's saltier now with all the Damn crab pots in the channel, i'm able to catch a dozen crabs off my Marina docks

Don't get me started on the crab pots! Occoquan Bay is a mine field this time of year!

Let me know if you ever venture up north! We've been staying mainly near DC this summer because our beagle has been sick.

 

[Ray Ray]

Today when I took my boat out to test everybody's techniques ie tab trims at 0 and power trims at short burst or trim down, etc. I noticed a drop in Rpms or a jump in Rpms with different combinations, but I always saw in drops in speed. I watched where my wake was created under the boat and how my rooster tail trailed. At the best combination, I set trim back to zero, lowered the tabs to about 50% and set cruise control to 3450, my speed raised to a steady 27 mph, burning @ .08 mph.

Now these numbers sound closer to normal, and all things considered, I think you're right about where you should be, performance wise. Overall, you'll need to find the sweetest configuration of drive trim and trim tab application based on running weight and conditions, but based on your test yesterday it sounds like the boat is running as designed. You'll just have to keep playing with it and get comfortable with it.

And yes, the crab pot placement in and around Aquia Creek, and the mouth to the river right now is insane.....It's a minefield at minimum!

 

[Sous]

Today when I took my boat out to test everybody's techniques ie tab trims at 0 and power trims at short burst or trim down, etc. I noticed a drop in Rpms or a jump in Rpms with different combinations, but I always saw in drops in speed. I watched where my wake was created under the boat and how my rooster tail trailed. At the best combination, I set trim back to zero, lowered the tabs to about 50% and set cruise control to 3450, my speed raised to a steady 27 mph, burning @ .08 mph.

Actually, that doesn't sound too bad to me. With the extended platform you are adding a bit of weight all the way at the back that would have some impact.

 

[bankyf]

Today when I took my boat out to test everybody's techniques ie tab trims at 0 and power trims at short burst or trim down, etc. I noticed a drop in Rpms or a jump in Rpms with different combinations, but I always saw in drops in speed. I watched where my wake was created under the boat and how my rooster tail trailed. At the best combination, I set trim back to zero, lowered the tabs to about 50% and set cruise control to 3450, my speed raised to a steady 27 mph, burning @ .08 mph.

If you upgrade to a Vesselview 7 it has an eco mode that will tell you exactly where to set the throttle and trims for max economy. It also adds cruise control and troll control for DTS equipped boats. Unfortunately, with inboards, the eco mode is inactive on mine. If things don't work out with Ray Ray and you want another opinion, I believe he is in a slip directly across from me with the amazing custom bimini top. Up until this boat, all I have ever owned is stern drive boats, so I am very familiar with them. FYI, Hope Springs fuel was $2.89 last week and it may have dropped a little with the new load they received earlier this week.

 

[Ray Ray]

If you upgrade to a Vesselview 7 it has an eco mode that will tell you exactly where to set the throttle and trims for max economy. It also adds cruise control and troll control for DTS equipped boats. Unfortunately, with inboards, the eco mode is inactive on mine. If things don't work out with Ray Ray and you want another opinion, I believe he is in a slip directly across from me with the amazing custom bimini top. Up until this boat, all I have ever owned is stern drive boats, so I am very familiar with them. FYI, Hope Springs fuel was $2.89 last week and it may have dropped a little with the new load they received earlier this week.

If you mean my snazzy, home-made spandex shade screen, then yeah.....that's me :grin::thumbsup:!!!