Seajay 5m Barramasta repower

[NAGG]

For the past 4 years I've lived with a barely tolerable boating package - The hull was just meeting expectation ..... It was certainly stable , ride was ok but somewhat wet. Deck layout is outstanding. But there was something not quite right ..... :-? When it came to the F70 yammi I was quick to learn that fishing 2 up was ok ..... but add a bit of gear & you needed to play around with props - A light motor on the back & a big battery up the front ( along with typical anchors etc ) gave the boat a nose down attitude & clearly attributed to the wetter ride.
With most of the runs limited to Northern enclosed waters .... it was tolerable . However after a move back south & the desire to fish some old stomping grounds which involve the odd bar crossing a decision was made to repower the Seajay. I decided to stick with Yamaha & go for the maximum power rating (100hp) - prop configuration was to be decided .

Once fitted the boat certainly looked a better balance & that certainly showed on the trailer ( a trailer adjustment was required to put more weight on the towball) - particularly going with a duel battery arrangement. 113474

On the water spinning a pretty standard Aluminium (13 1/4 x 17) after the initial break in WOT she hit it's max 6000 rpm - 34knots (63 km) . I then fitted a 4 blade stainless (13 x 17) which saw 5900rpm & 66.9km/hr (36.1) ..... GPS figures 113480 At 4000 rpm (43km / hr) she is burning 15 Lt / hr ..... Interestingly this is what I was doing with the 70hp ..... but at 6000 rpm .... 30% more fuel

The new 5" LCD display is a improvement 113476 & pretty easy to navigate

The big surprise was that the boat as an overall package is so much better ..... aside from being quicker - it is drier (having run it through a choppy Broken bay) .

The only downside is that the boat needs a bit more trim at lower speeds - with a tendency for nose up or to porpoise (slightly) ..... which I plan to iron out with the use of a SE400 foil . But all up it seems to be well worth the investment .

Chris113479

[Noelm]

As has been said many times before, the right motor for a boat makes all the difference, too small, and things are "OK" to big (heavy) and things are "tolerable" but when it's right, things are just so much better.

[aussiebasser]

I'd try a 16" prop with more rake and a bit more cup. Should give you some extra lift to keep the nose up. I'd also try a 3 blade prop with a bigger blade size. If you're not reaching maximum rpm and you're only running one up, she'll struggle with more weight.

[Tim_N]

Chris,
Whack a stain;less Solas prop and a True tracker on it and then watch her go!
And also, watch you fuel consumption improve too, It happened to me.
Tim

[NAGG]

As has been said many times before, the right motor for a boat makes all the difference, too small, and things are "OK" to big (heavy) and things are "tolerable" but when it's right, things are just so much better.

Too right ..... & it is a big difference in buying a second hand boat where you can go for a run and pick up on its traits - putting together a new package is a totally different subject . I went for a run in pretty well the same hull with a 70 yammi on the back & she got out of the hole well & hit 50km / hr ...... so what changed you could ask? For starters the helm position was moved - add a live bait tank & leccy motor .... with a thumping big 200amp AGM & the whole dynamics changed . ....... unfortunately for me - that killed the performance.

Now it's just a totally different boat ....... a few tweaks here and there & it will be the boat I always wanted . Fortunately the cost penalty wasn't too bad

Chris

[NAGG]

Chris,
Whack a stain;less Solas prop and a True tracker on it and then watch her go!
And also, watch you fuel consumption improve too, It happened to me.
Tim

Hi Tim

I'm running a solas ss prop

Forgive my ignorance but what is a true tracker ?

Chris

[NAGG]

I'd try a 16" prop with more rake and a bit more cup. Should give you some extra lift to keep the nose up. I'd also try a 3 blade prop with a bigger blade size. If you're not reaching maximum rpm and you're only running one up, she'll struggle with more weight.

Hi Dale

I'm getting 5900 rpm & Yamaha quote 5000-6000 as the rpm range which doesn't leave a lot more to ring out of her . The motor installer did say the 16" was an option .... but we were talking basic alloy props.
Going the four blade was about getting out of the hole quickly which it does ....... this is what I want for bar crossings.

In all honesty though ..... I'll be flip flopping between a alloy prop for the trips up north (prop crunching rock bars / timber in the impoundments) & the stainless for the offshore / inshore stuff down here ...... I'll see what happens with the SE400 hydrofoil

Appreciate your input

Chris

[Tim_N]

Chris,
It is a planning plate, like a SE400, but better, in my opinion.
I had a SE on my F115 then went to a True Tracker (available from Solas) and it went sooooo much better.
Tim

[aussiebasser]

Normally with a four blade prop, you go down an inch in pitch compared to a 3 blade. So if a 17" 3 blade alloy prop was good, a 16" Stainless would be similar (less blade flex in stainless) and 15" 4 blade should be comparable. I like to be hitting the rev limiter when I'm on my own so that I know I can get the best when it's loaded up a bit. With the playing around I did with my 150 and motor set-back, height and ECU tweaking, I went up from a 23" 4 blade to a 25" 4 blade and I'm still hitting the 6410 rpm limiter. I still think 4 blades are a bitch to reverse though. The 100 will give you a surprising amount of extra torque for carrying weight too.

[Moonlighter]

Congratulations on the new motor transforming your rig!

Now, you mentioned that with the new motor, you've seen a tendency for the boat to run bit nose up and experienced slight porpoising. And that now you're considering fitting a foil.

One of the potential causes of that kind of a stance and the porpoising is a motor set just a bit too deep. I found exactly the same thing on my previous boat, the SE sport i fitted helped, but by lifting it one hole higher it came extremely close to completely eliminating it. I was able to leave the SE Sport off after i did that, as it just wasn't needed any more. I wished I had known the benefits of lifting the motor one hole to start with, and that I realised that the foil was treating the symptoms, rather than the root cause.

So you could consider lifting it one hole higher before you try the foil, regardless of which type.

Now that would be assuming that with the new stainless 4 blade, you've got great grip on the water and no tendency for the prop to let go. If it is currently hanging on really strongly, good chance that it will still be OK one hole higher. Plus, you would save the cost of the foil and not have to drill any holes in that shiny new motor!

[scottar]

Also worth trying the Solas "Lexor" 3 blade if they make it in a size that suits. Jumping onto the plane won't be an issue if the pitch is right. With a 17 " Solas 4 blade and the 17" BRP Rebel ( Solas Lexor by another name) there is very little difference in performance on my rig in that regard. There is however a pretty big difference in mid range economy - at least 10 - 15 percent. There is maybe a bit extra vibration but that would be the only downside.

As for the foil, you will know the first time you get caught in some snotty conditions whether or not the boat planes slow enough. If it doesn't then bolt one on.

[NAGG]

Congratulations on the new motor transforming your rig!

Now, you mentioned that with the new motor, you've seen a tendency for the boat to run bit nose up and experienced slight porpoising. And that now you're considering fitting a foil.

One of the potential causes of that kind of a stance and the porpoising is a motor set just a bit too deep. I found exactly the same thing on my previous boat, the SE sport i fitted helped, but by lifting it one hole higher it came extremely close to completely eliminating it. I was able to leave the SE Sport off after i did that, as it just wasn't needed any more. I wished I had known the benefits of lifting the motor one hole to start with, and that I realised that the foil was treating the symptoms, rather than the root cause.

So you could consider lifting it one hole higher before you try the foil, regardless of which type.

Now that would be assuming that with the new stainless 4 blade, you've got great grip on the water and no tendency for the prop to let go. If it is currently hanging on really strongly, good chance that it will still be OK one hole higher. Plus, you would save the cost of the foil and not have to drill any holes in that shiny new motor!


Thanks Moonlighter

When we set up the motor we actually set the cav plate around 1" above the keel - there is scope to raise it 2 holes

I actually tried some high speed turns to see if it would let go & it didn't .....

The beauty of the SE400 is that you dont have to drill ..... that's why I I'm going that way

Chris