Official 390DA Thread

[Robert Hornedo]

Looks great

 

[Jus Cruisin]

The black piece. Is it a sunlight that’s on the older 390s but not the newer ones?

Ah, yes. It's a sunlight. There's a sliding cover in the cabin. The 390 was renamed 40 in 2006, I think

 

[jmauld]

Ah, yes. It's a sunlight. There's a sliding cover in the cabin. The 390 was renamed 40 in 2006, I think

Wish mine had that!

 

[Jus Cruisin]

This was our project we have a small vibration, so … shafts measured came out ‘perfect’, cutlass bearing is good, decided to pull props and get them reconditioned. Won the award at Sassy where we store her on the most people required to take off port prop… I am thinking they have never been off. Feedback is they were not so bad, prevailing thinking is the vibration is an attribute of the tunnels in the hull with respect to where the props are… seems plausible / I can understand the physics. I’ve been on one other 390 which felt similar albeit a bit less that was a regular 8.1 vs ours as HOs. Others have small vibration at the stern?

Prior to bringing the boat up last year I had a vibration from a loose motor mount found in the sea trial which also created a minor shaft seal leak. So I had both seals replaced and had the props inspected which were within spec. Finally had new plugs and wires installed early in the summer and didn't notice much vibration after all that maintenance.

 

[Jus Cruisin]

Bow in? I think we are likely in same place considering to bow in this year.. also was part of our rationale to buy a small center console … to check out the lake before we took the big gal out.

Are you going to use rack storage at Belle Maer for the CC?

 

[BuLion]

Are you going to use rack storage at Belle Maer for the CC?

We had thought about it as it offers some conveniences ... and its in there now for the winter, but most likely not.

 

[BuLion]

Prior to bringing the boat up last year I had a vibration from a loose motor mount found in the sea trial which also created a minor shaft seal leak. So I had both seals replaced and had the props inspected which were within spec. Finally had new plugs and wires installed early in the summer and didn't notice much vibration after all that maintenance.

Good catch on the motor mount, i've heard this before. These engines are hard on plugs for what ever reason, guess as much as it likes to eat fuel it also likes some substance too

 

[kiaman]

Has anyone played with their props

2011 39 sun dancer, bravo3 with a 22.5 pitch

was looking for a little more top end speed going to a 23.5 or 24. Open to ideas

 

[Redhook98]

Has anyone played with their props

2011 39 sun dancer, bravo3 with a 22.5 pitch

was looking for a little more top end speed going to a 23.5 or 24. Open to ideas

Did not know that boat came with I/Os as an option. ?? Whats your max RPM with the props currently installed? Usually going taller will work the engines harder and is undesirable. Shorter engine life and much more wear and tear. Plus it makes it much more difficult to get out of the hole with a full load. Diesels are much more forgiving in this area due to the low end grunt.

 

[kiaman]

about 4400 rpms

 

[Redhook98]

What are those motors rated for that year for max rpm?

 

[kiaman]

4800 max
the 4400 only get me about 30-33 mph

 

[Redhook98]

You want to step down then, not up. Sounds like someone may have already put taller props on there. If your supposed to be hitting 4800, but only see 4400, you are propped wrong. Going taller will exasperate the situation and make it worse. I would step down 2 inches in pitch. 1-inch pitch is typically 200 rpm. You would be surprised at the performance difference that will make.

 

[kiaman]

so what you are saying is going from a 22.5 to a 20.5

 

[Redhook98]

Yep. You need to reach max rpm. If the bottom is clean and motors are in good shape, then you are overpropped. Over propping is bad. Imagine having your car in 4th or 5th gear at 20 mph and hitting the gas. That is a big load on that motor. Thats what over propping essentially does. What props originally came with it, do you know?

 

[kiaman]

22.5 lol

 

[Redhook98]

Crazy huh? I stepped down 2 inches from factory with my Bravo 2s in my 29ft AJ when I could not make max RPMs. Pretty common. Different boat when I put the new props on. Felt like new engines. Actually better top speed too.

When they determine what props go on your boat, they use a formula. Part of that formula takes into consideration only 1/4 tank fuel, minimum water and waste, 2 people and no additional equipment. Take a boat that is actually being used, with 4 people, 250+ gallons of gas, tools, water, beer, supplies and everything else, you get a much different situation. Add a RADAR, arch or HT and other electrical equipment and options, even worse. A lot of prop shops will let you "borrow" props to get you dialed in. Or you can call and talk to a reputable prop shop and they can walk you thru this.

Most boats are actually over-propped because people are trying to get more speed and do not realize what they are actually doing. The only real way to go faster is to lighten the load considerably, or make more power that can throw a bigger or taller prop.

 

[gerryb]

Got tired of not having enough any hanger space on "my" side of the v berth.

 

[Jus Cruisin]

New stern thruster was installed today. Scheduled launch. All that's left on the things to do list is bottom paint...... I think/hope anyway.

 

[liv2ryde100]

Hey guys new to the 390da thread but not new to the site, last boat was an 05 340 dancer, in contract now on a 07 40 dancer with qsb 380’s, just finished reading through all 30 pages on here! Lol survey tomorrow!!