Boat lists,porposes while on plane.

[Tail_Gunner]

Were the specs i posted correct for your engine and is it a two stroke?

 

[juicegoose]

Specs are right on and it is a 2 stroke.

Thanks

 

[Tail_Gunner]

Ok can you get your hands on a 24p alumn 3 blade for a trial..borrow one something like that. A base line need's to be established here...im convinced your banging the rev limiter and want to how much a 24 pulls down the motor if it does at all.....You could buy a new solas for $100.00 I cant help but think that 1.75 combo of 200 hp 3000lb boat...even a 25 or 26p I just need to see that engine being pulled down by a certain pitch and how much.

That rev4 has to be worth 300/400 if its clean,.

 

[juicegoose]

Thanks Gunner. I've got a couple buds that might be able to hook me up with a prop. probably won't be a 24p solas but it'll be another prop with either 19-21p. I bought the rev4 for 500 or so new but did catch a rouge oyster or something and dinged one of the blades a little.

Anybody interested in letting me borrow a test prop with the flow torque II style hub? I'd pay shipping.

 

[Tail_Gunner]

Thanks Gunner. I've got a couple buds that might be able to hook me up with a prop. probably won't be a 24p solas but it'll be another prop with either 19-21p. I bought the rev4 for 500 or so new but did catch a rouge oyster or something and dinged one of the blades a little.

Anybody interested in letting me borrow a test prop with the flow torque II style hub? I'd pay shipping.

24 to 26....19 to 21 wont get it I am sure.

 

[alldodge]

If you can get an accurate tach this to would give you needed info

 

[Barramundi NQ]

Seeing pictures of the boat in the water at speed and also the engine height (I think the engine is too high). Am I correct in the way the tunnel is designed? Its function is to form a slightly higher slab?? of water as it leaves the hull. This means to me that the anticavitation plate should be right in that target range of close to the slab of water. Am I right here?
Also juice have you weighed the boat? It seems very low in the water at speed with the nose deep in the water. this one has me stumped

 

[Fed]

From what I understand it's a pocket not a tunnel Barra much like some of the Haines Signature boats, the ones with the big pipe up through the deck to stop them sucking themselves to the water.
To my thinking at speed there should be clear air inside the pocket with the water shearing off the very bottom of the boat not the top of the tunnel.

 

[juicegoose]

The tach using was measured against a mercury technicians test signal. It was accurate to within 100rpm

 

[juicegoose]

So the pocket tunnel design on my boat is there to bring a column of water up higher then the bottom of the boat. Artificially raising the depth of useable water for the outboard. I guess it could be possible that I'm raising the outboard to much. I did try and look at the anticav plate at different settings. it was hard to see because just forward of the nose of the lower unit the water was being split and splashing all over. maybe by the little anodes on either side. I for sure saw the anticav plate though.

In regards to boat weight. The only numbers I can offer are these.
boat dry weight - 1550
Outboard weight - 500
Full fuel under center console(bottom of boat) - 300
Person onboard(just me in the pic - 170
Batteries, 4 in center console - 300 lbs

Trolling motor and anchor up front - 50
misc items in back of boat pump for power pole etc. - 75
jackplate - 40
power pole and bracket 30

that's about 3000 lbs rounded up. could probably add another 100-200 lbs just for grins.

I've looked online for pictures of various bayboats and their attitudes. Mine seems to be right in line.I'm sure if I put two adults in the rear jump seats I could probably trim it up a little more but I don't run WOT all the time.

 

[juicegoose]

I was over at the Nautic Star website and took a look at the performance data sheets for various motors. The Yamaha f200 has the same gear ratio as my optimax.

They only test it on the 22ft bay boat but there test numbers should be somewhat similar. Their test as loaded was at 3300 pounds. Me fully loaded with people should be right around the same.
They topped out at 56.4 mph at 5950 on the tach. here is the sheet
http://www.nauticstarboats.com/wp-content/uploads/2014/09/224-XTS-VF200LA-Performance-Bulletin.pdf

I don't have a need to go fast but hey if I could swing a 21p prop with 4 adults on board and get better cruise that would be awesome.

 

[alldodge]

Compare the engine mounting height to where yours was

 

[juicegoose]

Ya I saw that. I would imagine I need to measure from the top of my tunnel not the bottom of the boat. More testing next time I suppose.

 

[alldodge]

I take it as they measured from the bottom of the boat, might be wrong, but just my take

 

[juicegoose]

Ya they did but for my purposes I was roughly looking at the prop they tested with and at what weight. I'm sure my 200 would sling a 21p prop but at what rpm

 

[Tail_Gunner]

So the pocket tunnel design on my boat is there to bring a column of water up higher then the bottom of the boat. Artificially raising the depth of useable water for the outboard. I guess it could be possible that I'm raising the outboard to much. I did try and look at the anticav plate at different settings. it was hard to see because just forward of the nose of the lower unit the water was being split and splashing all over. maybe by the little anodes on either side. I for sure saw the anticav plate though.

In regards to boat weight. The only numbers I can offer are these.
boat dry weight - 1550
Outboard weight - 500
Full fuel under center console(bottom of boat) - 300
Person onboard(just me in the pic - 170
Batteries, 4 in center console - 300 lbs

Trolling motor and anchor up front - 50
misc items in back of boat pump for power pole etc. - 75
jackplate - 40
power pole and bracket 30

that's about 3000 lbs rounded up. could probably add another 100-200 lbs just for grins.

I've looked online for pictures of various bayboats and their attitudes. Mine seems to be right in line.I'm sure if I put two adults in the rear jump seats I could probably trim it up a little more but I don't run WOT all the time.

I am almost certain your underpropped both props even that hacked 21 went to 5400 and stopped. the 17 should have taken you to 5750 with ease and I am sure it did that alarm was the key....Odd don't you think a 21 and a 17 pull to 5400 exactly.... Now aside from that any 200 hp boat with a 1.75 gear ratio at 20' will swing a 21 with ease I/O's....and they are heavier by 800lbs along with drives that are far less hydro dynamic...The engine is not to high one you would have blown out at the first turn and two she would have over heated almost instantly which it did not do.... indicating the water pickup was well with in the water column...most bass boat's run so high in the column they have to install water pickup's.

If you can get a 24p loaner I believe you will be surprised...the rev4 is a prop that works well running deep you see it being used a lot on high horsepower deep v I/Os quite a bit...Your application lends itself to cleaver type props that run well high in the water column hence the fxp/txp....along with that they carry weight very well and advertise minium bow lift....aka porposesing

Your trying to find where your engine runs out of touqre first...aka pitch......... then select and prop that fit's your hull type or compliments that....but first you need to find a prop pitch that pulls that engine to to at least 5200 rpm

 

[juicegoose]

How would you recommend I test this 24p prop? By that I mean test it at my typical load with people on the boat or test it light?

 

[Tail_Gunner]

For now it doesn't matter your just trying to find a pitch that pulls down that engine to below 5400..5200 or less tells you that things are working..a pitch that drag's her down working hard etc. You could always fill a few bags of sand for any weight you want to test at. Once a pitch is established then comes selection... ...As you already know a WAG can be a very expensive error..

Below is a link where I had a heck of time getting things right.

http://forums.iboats.com/forum/gener...-sport-s-cuddy

As to running to deep with a pocket tunnel here's a factory setup

 

[juicegoose]

Quick question here. What is the technical term for the plate just above the anti vent plate that pushes out forward instead of back like the vent plate? Splash guard?

 

[juicegoose]

Could it be possible that the Rev4 actually doesn't have enough bow lift to keep the bow elevated at a given rpm instead of the opposite that we have been thinking? Is there anyway to test this? Would adding more weight up front(people) and then trimming show whether more stern or bow lift is needed?

Just thoughts.