Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Raising the motor worth it?
Posted by jb4146 on 10/01/09 - 5:23 PM
#1
I have an Evinrude 48hp SPL - with trim and tilt - mounted in the lowest position on my classic 15. The lower bolts are through-bolts (not lag screws) in the lower "blind" holes on the engine bracket. My anti-cav plate is perhaps 1/2" below the keel line with the motor trimmed all the way down. I have an aluminum 11-3/4x17 prop (recommended size) of unknown pedigree. No tach, so I don't know where I am at WOT (4500-5500 per spec). By GPS I'm topping out at 32-33 mph with a light to moderate and balanced load. I'm considering raising the motor 1 or 2 holes up as I have read in many posts a higher position is preferred and recommended. This would be a winter project. I don't have any handling problems now that I am trying to remedy, but would like the reduced draft and wouldn't mind perhaps a slight speed boost and any improvement in fuel economy. On the flip side, there's the work involved in raising the motor, drilling new bottom holes, and filling/dressing the old lower holes. Also wondering if the new lower holes can be drilled with the motor in place. I don't think I'm interested in going with a jackplate. Any thoughts or opinions would be welcomed.
Jim
Posted by Tom W Clark on 10/01/09 - 5:30 PM
#2
Yes, it is worth it.
No, you cannot drill the new holes with the motor in place. You really need to remove the motor to fill the old, clean up the transom and drill the new. Not a big deal.
Posted by floridaskater on 10/01/09 - 6:52 PM
#4
isn't a jig a good idea for drilling these holes? I've heard of problems when you don't use a jig.
Posted by Tom W Clark on 10/01/09 - 7:10 PM
#5
A jig is nice, but not necessary; a good layout is necessary. It is also important to drill "square" to the transom.
Posted by russellbailey on 10/02/09 - 5:26 AM
#6
Having a 1980 15' Striper with a 70 hp Evinrude, I was in the same situation - mounted all the way down in the blind holes.
I would really recommend trying a jackplate first - I like the Bob's 4-in-1 convertible. After adding this in the 5" extension mode, I am up between 5"-6" from the original mounting location, have no problems with prop slip, and the Doel-Fin rides just below or right at the surface.
The work to add a jackplate is not a lot and I'd think less than re-drilling the holes and patching them. Plus, you can go up a lot higher and thus run notably more shallow. You can use the original blind holes with the jackplate - you just have to drill 2 new lower holes in the jackplate.
Posted by CES on 10/02/09 - 11:43 AM
#7
Go for it, it's totally worth it!!!
Posted by jb4146 on 10/02/09 - 1:21 PM
#8
Thanks all for your input. Looks like I have my first winter project lined up.
Joe,
Appreciate the link - I had been studying that article and drawing before my original post. I'll likely go with new lower (green) holes from the drawing, allowing me some adjustability to go up 1 or 2 holes from where it is now.
Tom,
Point taken, if not a jig, I'll at least use the diagram from the article as a scaled template. For the old holes, softwood plugs and resin underneath the Spectrum gelcoat patch cosmetic repair.
Russell,
Good point on the jackplate, and the Bob's 4in1 looks slick. But unless I can find a suitable plate in the next few months at a a steep discount, I'll probably just go with new holes.
Jim