Question; Repower a 38ft flybridge with 2 or 4 outboard motors?

[Nick Quinlan]

Hi I was given a boat - 38ft Gulf Craft Flybridge 1991.
Originally had volvo penta sterndrives


When I got her she had Yamaha I/O sterndrives 6cyl diesels x2 which were shot to bits and spares not available.
So I opted to re-power with outboards.


The convertion went well but I made the mistake of buying cheap 2-strokes to test the boat.

I am now looking to repower and have 2 options;

2x 350hp
or
4x 250hp [2x 30inch shafts and 2 x 25inch shafts]

The price is similar and I would love to put 1000 horses on the back.
Transom is very strong 12 inches thick and braced
Back is light now [because I removed the diesel I/Os]



Is a 4 engine setup feasable? Any big negatives to this slightly mad plan?

Would appreciate your suggestions. Thanks

 

[GA_Boater]

You are going to need a new bracket to hold 4 OBs. If you have the time and money, well, it's your time and money. How about 3 350s? Then 1050 horses.

 

[Nick Quinlan]

Agreed - will need a new bracket [which will be a displacement one this time to add bouyancy].

Well the boat needs 350 pair minimum to run well - existing 300s go but not fast.
The 350s and 300s are disproportionately more expensive than the 250s
2 x 350s are nearly the same price as 4 x 250s which got me thinking which is the better set up?

 

[dingbat]

Four is 25% more problems than three. I would add a third 300 to the mix and call it good

 

[Nick Quinlan]

Good point more maintenance on 4 but good for offshore to have some redundancy buit in? I dont think I can run a 3 engine rig as the two existing engines are already 30 inch shafts.(longest) so I would need a transom jack to put a third engine in running position behind the centre of the chime. Thats why im looking at 2 or 4 engine solutions. thanks for the suggestion!

 

[Scott Danforth]

I would leave it an I/O myself. however if you are bound and determined to go outboard, then go with twin 557's from Seven Marine

 

[Nick Quinlan]

Scott thanks for the heads up but without even checking I know the 557s cannot be serviced where I live [Oman]. Here Suzuki, Honda and Mercury have the best service and anything else is risky.

Here are the repowering quotes I have so far and rough reasoning why 4 engine rig maybe the way to go;

$122,000 Repower with the biggest Yanmar Z drives x2 available I/O - not going to happen could buy a new boat for that!!

$72,000 for 2 x Mercury verado 350 engines - ok but alot more money for 50 hp more
$62,500 for 4 x Suzuki 250 engines with bar assembly [plus new transom bracket $4000] alot of money but you get 1000 horses
$42,640 for 2 x 300 Verados - maybe underpowered
$41.600 for 2 x 300 Suzukis. - maybe underpowered

The 300s will really struggle with such a heavy boat. The 350s are sooo much more? This is why im tempted to do the 4 engine option and get alot more HP for similar cash.....

 

[Nick Quinlan]

also just noticed the 4 engine quote includes 4 marine batteries and $3000 sea star hydraulic steering.

To pay for the engines I am bringing in 2 partners on the boat - they are going to pay for the repower and after that its a 3 way ownership. They are both existing boaters with 26ft boats.

Big sacrifice but free repower and 1/3 marina and maintenance bills I reckon its worth it! Boat will get more attention too!