Honda BF350 on Canyon 306

[Sardinia306Canyon]

My friend who is Suzuki and Honda dealer just sent me 3 photos of one BF350 they temporary bolted on for test purposes to see how engine tilts out of the water due the much higher engine cowling.
Surprisingly the BF350 seems to tilt fully up, but it's a tight fit and on the photo the water line seems to be below the waterline and lower unit will not or a a bit stay partially submerged. However, in a few days they will bolt on the second one and then we drop her for a float test to see how deep the lower unit will be submerged, if so.
He mentioned also that there may be a problem with the hydraulic steering hitting the splash well and what i foresee is that we have to relocate the rigging tube attachments as they probably will limit engine tilt.
I will move back to Sardinia this weekend and report back when we dropped her and i decide to keep the engines or get twin DF300P instead.
Chris

 

[Sardinia306Canyon]

They bolted on a second BF350 but a XXXL version what does not matter for the floatation test, holy moly they look huge!
monday morning we will drop her with the crane to see how much the lower units remain submerged and if that would be acceptable, or not.
As long the fin and/or nose is a bit submerged i have no problem with that, if the water cooling grilles and conducts are then i have to choose the DF300AP as she lives 10 month in a slip and marine growthwill be a issue then.
From the photo it seems that a setback bracket may not help a bit, but then the rigging hose has to be relocated (still wondering why GW put them directly behind the engines) and the old holes glassed shut and gelcoat sprayed what will be a PITA. Only option what will help would be a hydraulic jackplate but that rises my repower budget even more, add another 100 lbs to the stern and i had bad experience with the Seastar Hydraulic Jackplate so i prefer to not have them again.
Chris

 

[family affair]

As great as it might be to have the extra HP, you might find the juice isn't worth the squeeze!
That looks like a lot of weight for the back of a 30ft cc.

 

[Sardinia306Canyon]

As great as it might be to have the extra HP, you might find the juice isn't worth the squeeze!
That looks like a lot of weight for the back of a 30ft cc.

It's not the extra HP, it's the lower fuel consumption and the higher torque what interests me, when i can cruise at 28 knots at 3500 rpm then i am more than happy and that would be at least 20% fuel savings.
The BF350 weight about the same as the F350 the 306 Canyon was available, extra weight is about 400 lbs to the F300 i had installed.
260 kilo 2011 Yamaha F300
357 kilo BF350
360 kilo F350 V8
When i stand with my 220 lbs on the transom the slightly immersed F300 lower units sink about 2 fingers deeper what would be acceptable.
However, it is a test my friend, Honda Italy and i is interested to conduct, if it does not work then i will get the DF300AP.
Chris

 

[family affair]

I'm curious. How do you know your fuel consumption will be 20% lower at that rpm?
Depending on how bad you you want the 350s, you could counter balance the other end of the boat with sand or water in buckets that get removed before you head out.

 

[Sardinia306Canyon]

I'm curious. How do you know your fuel consumption will be 20% lower at that rpm?

I had last year around 4200 rpm to get 26 knots, if i can do 3500 rpm it will save already a lot and the BF350 is known for a extremely low fuel consumption.
There is no need to add buckets, as i wrote above, two BF350 are bolted on and on Monday we will drop her with a crane and slings to verify how she rest in the water without the engines working. Then i will decide if i keep the BF350 and finish to install them or tell my friend to order two DF300AP instead.
Chris

 

[JJF]

Here is how mine sits with F350s

Post in thread 'Show Us Your Grady'

Nov 16, 2022

• JJF

• 

 

[Sardinia306Canyon]

So,
we put her in the sea and the test was positive.
The tip of the lower unit remain a bit immersed, but the intake grille not what is acceptable.
The boat is completely empty, just about 3/4 of fuel (200 gallons approx) so i estimate with the the added weight of the life raft, the to install Garmin Kraken and a 36V LiFePo battery on the bow plus the other zillion of things i carry the floating level should be better to same.
So i pulled the trigger and told my friend to order two new ones to install, same in white as the ones used for the test go on two other boats and i get new ones and both the correct LU length (the stbd engine on the photos is a UL model bolted on for this test)

 

[Fishtales]

Big weight difference with twins (Honda vs Yamaha 350) I'd be checking with the factory before I commit to a purchase.

 

[Sardinia306Canyon]

Big weight difference with twins (Honda vs Yamaha 350) I'd be checking with the factory before I commit to a purchase.

There is no big weight difference at all, it's the opposite

804 lbs 2011 F350 V8
770 lbs Honda BF350
The 306 Canyon came with the option for the V8 F350, also mine and it has 700HP written on the CE plate

Chris

 

[Sardinia306Canyon]

Work in progress
Cable looms and BCM are installed, Gauges and controls as well.
Still waiting that new bang cap is finished and then the engines can be mounted.
New GT51M-TM, Fresh antifouling and ready to drop she is.
Chris

 

[Sardinia306Canyon]

The photo below is from yesterday, today we finished 99% of cabeling, steering pistons, i guess we will drop her next week:
I installed also from Garmin a MSC10 satellite compass, a VHF 215 AIS, a GSD26 echosounder blackbox, but the Kraken trolling motor is here but i need more time to install it.

 

[Sardinia306Canyon]

So we dropped her in the drink today and i brought her 30 miles south to my marina.
I am still with a big smile about this engine change, as i already knew, extremely quiet, powerful and fuel efficient.
As i have to break them in i could not conduct extensive tests, but at cruising speed of 25 knots i experienced a whopping 15-20 gph lower fuel frow, much more savings than i expected.
However, i will conduct extensive tests later and post the results of the twin F300 and the new BF350.
Surprisingly even full with 300 gallons of fuel, water but only 2 persons and basic gear the lower unit is about same submerged as the F300 were and i am happy about that as this was my biggest worry.
Chris

 

[family affair]

Congrats Chris!
We need to see photos of the business end of the boat!
Are you sure that fuel flow was for both engines?

 

[Sardinia306Canyon]

Congrats Chris!
We need to see photos of the business end of the boat!
Are you sure that fuel flow was for both engines?

Thanks,
yes both engines and more photos will follow.
What are photos of a business end?
I can cruise steady at 3200 rpm making 20 knots and 3500 rpm making 25 knots @ around 19 gph
Last year when i bought her i made 25.7 Knots @ 4300 rpm @ 29 gph, same 3 persons, basic gear and 300 gallons of fuel but antifouling slightly slimy.
Yamaha F300 had 3x15.5.x17 Yamaha Saltwater II props, now i have 3x16x18 Honda Propellers.
Top speed at WOT raised from 41 knots to 44 knots, but could do only a very short wot run.
From my experience i would guess the BF350 would be a huge benefit over the F350 V8 on a 330 Express, or the Marlin (if she can take 700 HP)
Chris

Values are in Liters/hour but 36.5 l/h x 2 = 19.2 gph and i took the photo at 25 knots and no trim, trimming up to 50% would give a vene better result.

 

[Ekea]

in this context, the business end would be the stern with your new power. its a figure of speech in US english referring to the end where "all the business" is happening. with a chain saw, it would be the chain end; with a gun, it would be the end of the barrel...

congrats on the new power, its nice to have new stuff

 

[Sardinia306Canyon]

Thanks for explaining Ekea, this was a unknown phrase to me.
Above, a few treads earlier is a photo from the stern when we did the float test with the engines only bolted on,
but i will try do do some more rear end photos to show that they look sweet.
Chris

 

[Sardinia306Canyon]

I went out today and it was almost glassy and did also some speed / fuel flow test

2011 Yamaha F300 4.2L Saltwater II 3x15.5x17 propeller
2025 Honda BF350 V8 Honda 3x16x18 propeller

8 knots for trolling
F300 1700 rpm - 4.9 gph - 0.6g pm - 41% prop slip
BF350 1850 rpm - 6.9 gph 0.78 gpm 48% prop slip

Best fuel economy
F300 3500 rpm - 19.2 kt - 17.2 gph - 0.9 gpnm - 31% prop slip
F300 4000 rpm - 23.4 kt - 23.2 gph - 0.99 gpnm - 27% prop slip

BF350 3050 rpm - 19.8 kt - 14.5 gph - 0.73 gpnm - 22% prop slip
BF350 3300 rpm - 22.9 kt - 16.6 gph - 0.73 gpnm - 16% prop slip
BF350 3450 rpm - 23.8 kt - 17.4 gph - 0.73 gpnm - 17% prop slip

Fast cruise
F300 4700 rpm - 29.8 kt - 37.6 gph - 1.26 gpnm - 21% prop slip
BF350 4100 rpm - 29.7 kt - 26.2 gph - 0.88 gpnm - 12% prop slip

WOT
F300 5500 rpm - 36.2 kt - 52.4 gph - 1.45 gpnm - 18% prop slip
BF350 5650 rpm - 43.6 kt - 64.72 gph - 1.48 gpnm - 7% prop slip

• Remarks
  The F300 had less slip below planing speed, but more at planing speed than the BF350
• a better working prop on the F300's would have given better results, but on the BF350 most likely too
• kt = knots
• gph = Gallons Per Hour
• gpnm = Gallons Per Nautical Mile
• Boat was similar loaded, 300 gallons of fuel and 2 or 3 persons, only safety gear, bottom was clean (F300) or freshly painted (BF350)
• The Honda Bf350 beats the F300 fuel economy, about 11 gph or 0.38 gpnm at 29 knots.
• In Sardinia and Europe 11 gallons of gasoline at the marina cost today about 95 US$

The above data show also the importance of a low propeller slip if fuel economy matters.

Chris

 

[Sardinia306Canyon]

As requested: here more photos from the stern area






The lower unit intake is still submerged, i will see if i can adjust tilt to tilt a tad more and shift some weight forward.
However surprising the this hull don't really sink deeper than the about 360 lbs lighter F300

 

[family affair]

Nice write-up Chris. Thanks for sharing. Great improvement.
Too bad about the lowers being in the water, but it looks like this isn't new to you.
I'll stop complaining about my $3/gallon fuel prices.