A27 Thruster Install

[TorreyWP]

I see thruster install questions come up fairly often but I had not really seen anyone (especially A27 folks) document a self install so I though I would start to post my progress installing a Lewmar 140TT gen 2 thruster.

I selected this thruster because it was a little more thrust than what I hear most people have installed on their A27's and also the price from WMJ Marine was awesome! Shipping was free and also really fast... Our boat is located on the upper Niagara River (before the falls) so there is a considerable current going in one direction all the time and the area is subject to some serious cross winds that come off the lake. Couple all that with tight fairways in local marinas and ports all made this addition attractive. I will note that these boats do maneuver better than lots of single prop boats that I have handled without a thruster but it is time to join the club.

The biggest concern was locating and cutting "the hole". There are several factors obviously, install requirements and interior bulkheads that needed to be cut away but again, it was hardest to wrap my head around the actual cut. Hire Florida Bow Thrusters? No. Buy the big elongated hole saw? No.... How about this rig:

Thruster jig.jpg

By simply finding the center hole of the tube and cutting a hole big enough for a pipe to go through both sides of the hull, a die grinder attached to the pipe (with the outside edge of the cutting bit being half the diameter of the outside diameter of the tube) would allow for the curvature of the hull side.

After lots of measuring, double checking, reading the instructions and interpreting Lewmar's requirements, triple checking, using large magnets on the inside and outside of the hull, quadruple checking, over thinking it then one ice cold shot of tequila....I cut the center hole.

Happy with the location from the view point of all requirements and being straight, centered and aligned, I fit the pipe with the die grinder set up and cut the holes. It is important to note not to cut all the way through on either side but to just score the hull most of the way through to maintain the center hole on both sides. Then I removed the pipe and finished the cuts with the die grinder, sawzall and angle grinder. The tube fit tightly which is nice, now I have fiberglass work cut out for me...

Progress so far is pictured, I will try to update as I go along.

[Norseman]

Wow, do it yourself instal..

65DC9094-C32A-470A-8FEF-CCB6C0C4F206.jpeg

[DesertAlbin736]

One person to ask about thruster installations is Tribologist, aka Ulf, owner of A25 "Driftless'. He installed one in his boat a while back

Niagara River before the falls? I hope so! Over the falls would not be good. We hauled our A25 out there to Tonawanda last August & scouted Gratwick Park launch ramp as a place to put in. The current looked too strong & the dock to flimsy to mess with trying launch a 6.5 knot boat with a 24 HP engine there. So we ended up launching on the canal east of Tonawanda. Also only making it as far as Baldwinsville before we gave up on on the muggy weather & storms.

[WillieC]

Nice work! Measure twice….

[motthediesel]

That die grinder setup is quite brilliant -- well played sir! I guess you could have aligned a sharpie the same way, but a ground-out groove is a better cutting guide for sure. Another example of where hose clamps save the day -- they are the handyman's secret weapon.

[TorreyWP]

Just wanted to update this post for anyone interested. I got the boat in the shop last week so I could go to town on the fiberglass work related to the thruster install. I really went down a rabbit hole about the front edge flair and how it truly makes water (and more importantly in my opinion; debris) glide around the hull. I had a pretty good radius on the edge that was described in the manual but after comparing the flair on other boats in the yard, I decided to build up the edge about 3/4" and blend into the hull. Not 1 SeaRay in the yard has any contour on this edge, Carver does, the two Mainships in the yard both have a HUGE flair and one Albin 28 has a moderate flair. I settled somewhere in the light to moderate flair and stopped messing with it after 4 applications of flaring compound and glass, sand and repeat....

Thanks for the comments! Cant wait to try it out!

[WillieC]

Looking good! What kind of solvent/additive/thinner is in the open brown bottle on the table? You'll find a sampling of local hazy IPAs whenever I'm in the shop.

[tribologist]

Nice!! Next time you are doing glass work, try to get 1708 biaxial mat. Weave is really hopeless to work with in comparison. 1708 flows quite well in corners and is easier to wet out.

[DesertAlbin736]

Very professional job! Oh to have access to that kind of building to be able to work in!