2007 200 DAUNTLESS: Bow-mounted Trolling Motor

[Redfish12]

I plan to mount a Minn Kota Riptide Terrova trolling motor on the bow of a 2007 200 DAUNTLESS, which has the optional fishing package which includes a pre-wired electrical connector and added reinforcement at the bow. The standard mounting directions for a Minn Kota Riptide Terrova trolling motor instructs they are to be through-bolded to the hull. This is not possible with a 2007 200 DAUNTLESS because of the Unibond hull foam core.

Here is my plan:

• I will use the Minn Kota RTA-17 quick release bracket that requires 6 x4-inch base plate to be attached to the bow using four 1/4 x 20 bolts, and to locate the base plate so that the shaft of the troller motor clears the hull by 1.5-inches;
• because of the curvature of the bow, I do not believe the embedded reinforcement in the hull extends to the edge [of the hull at the bow], and therefore I think it is not possible to attach the base plate directly to the boat;
• a different mount, a side mount is available and is an option;
• I will make a simple extension platform out of 1-inch thick KING StarBoard to gain the extra three or four inches needed;
• the KING StarBoard extension platform will be fastened to the hull by machine screw fasteners that will be threaded into tapped holes in the embedded phenolic board reinforcement in the hull;
• I have information that phenolic board thickness is 3/8-inch, it should be drilled and tapped for the 1/4-20 machine screws;
• the Minn Kota base plate will then be attached to the KING StarBoard extension;
• I expect to be able one of the fasteners for the Minn Kota base will be able to align with one of the fasteners for the extension, so at that location I could use a longer machine screw and attached the Minn Kota base to the embedded phenolic material in the Unibond hull.

Please give me answers to these questions:

Q1: is my plan sound?

Q2: should I drill and tap all the way thru the phenolic and into the foam?

Q3: if I drill into the foam, what sealant should be used to seal off the foam?

Q4: is there a way to drill beyond the phenolic board and fill the hole with epoxy or caulking?

Q5: for the one-inch thick KING StarBoard extension, what width should the board be to distribute the force of the trolling motor hanging off the edge?

Q6: how many screw fasteners will be needed to fasten the KING StarBoard extension to the hull in order for me to feel safe?

Q7: is use of 3M4200 Adhesive (as recommended by some unidentified source) to bed the KING StarBoard material to the gel coat of the Unibond hull (in order to add strength to the attachment of the extension to the hull) a good idea?


ASIDE:

Other than one 2003 thread, I could not find any prior discussion about mounting a trolling motor on the bow of a 2007 200 DAUNTLESS. If there are prior discussions on this topic, please point me to them.

For some reason, the limited information I was able to get from Boston Whaler was not accessible directly from them but was only accessible by being relayed through a dealer.

Contact:
Mounting a trolling motor to bow of Dauntless 200
by Redfish12 » Sun Sep 29, 2024 6:24 pm

I grew-up using a Boston Whaler. I I just bought a 2007 200 DAUNTLESS. So far, the 200 DAUNTLESS seems like an admirable boat so far. I plan to use the 200 DAUNTLESS mostly for inshore angling. The installation of a bow mounted Minn Kota Riptide Terrova trolling motor with a feature called SPOT LOCK will be the first major upgrade.

[Phil T]

The entire archive of the forum can be searched using the internal search engine.

I know for fact there are at least 5 threads on bow trolling motor installs on the Dauntless 200, 210 models.

Here is the link to the search:
https://continuouswave.com/whaler/search.html

[jimh]

...6 x 4-inch base plate to be attached to the bow using four 1/4 x 20 bolts....

For attachment of a machine screw to a 3/8-inch phenolic board, I would not use 1/4-20 threaded fasteners. I would use a higher thread-per-inch, possibly 10-32 fasteners of higher strength than made-in-china-hardware-store variety. In the situation described, the strength of the fastener itself is not in any way a limitation. The limiting factor is going to be the strength of the attachment to the embedded phenolic plate. I am sure the phenolic plate will fail long before a stainless steel machine screw would fail. Because there is no limitation on the number of fasteners for this extension plate, you can use as many as you like.

For attaching the the trolling motor mounting plate to the KING Starboard extension, the existing holes on the trolling motor mounting plate will determine the location and number. Here again you won't be able to through-bolt (unless you remove material on the underside of the KING Starboard for a bolt head) With a one-inch thickness in the KING StarBoard, a 1/4-28 (fine thread) mounting bolt should give you very good attachment of the machine screw to a tapped and threaded hole the KING StarBoard.

[jimh]

Q7: is use of 3M4200 Adhesive (as recommended by some unidentified source) to bed the KING StarBoard material to the gel coat of the Unibond hull (in order to add strength to the attachment of the extension to the hull) a good idea?

There are several possible problems with this idea.

The principal concern is the strength of the bond between the KING StarBoard and the 3M4200. The KING StarBoard material is probably an ultra-high molecular weight (UHMW) plastic, and exactly how effective 3M4200 will be in creating an adhesive bond to it should be researched.

The second concern is the attachment of the 3M4200 to the deck gel coat. That might become so strong that removal of the extension plate may break off some gel coat or at least tear the gel coat away from its bond to the laminate, or in the worst case tear the gel coat and laminate away from the foam.

My unscientific opinion: just use a sealant between the hull and the KING StarBoard plate, and rely on the mechanical fasteners to provide the attachment strength. Using a really strong adhesive-sealant like 3M4200 might be a big problem in the future.

ASIDE: I have some experience with removing materials bonded to a hull with really strong adhesives. See my brief article at

Refitting a Depth Sounder Transducer
https://continuouswave.com/maintenance-logs/newDS/

[Redfish12]

I really appreciate the input.

Phil--I had not seen much about using an extension board for trolling motors, but I had seen a few of your posts about how to work around a bow rail and how to wire a bow-mounted trolling motor, which are more complicated problems. Those posts were actually very helpful in my search of this boat (particularly realizing that I wanted to make sure I bought a boat that was pre-wired from the factory for a trolling motor and I figured I would just do without a bow rail).

Jim--those are excellent points about mechanically securing the King StarBoard [to the hull]. I had not even considered the bond between the King Starboard and something like 4200. In doing a little searching, it doesn't seem like there is much that will stick to KING StarBoard or other HDPE boards. I will be focusing on the machine screws (probably several of them) as the main source of strength, as you said.

[jimh]

ASIDE:
When I suggested that you use finer-pitch threaded fasteners (higher number of threads-per-inch) I was going on my own intuition about those fasteners giving better attachment into thin materials. I searched for more advice on using higher TPI fasteners, and found this discussion, which seems to confirm my own opinion:

Thin materials and stronger fastening are both reasons fine pitched fasteners are used.

https://engineering.stackexchange.com/questions/52448/is-high-tpi-sheet-metal-screw-stronger-for-thin-materials

I have some experience in use of stainless steel fasteners into phenolic material from working on professionally made radio antennas. Phenolic material is often used on radio antennas because of its insulating properties and ability to maintain them even when wet, and also for good weather resistance. All the screw fasteners I have seen that were threaded into phenolic material were always the higher-TPI version of a particular fastener's size.

[Redfish12]

Interesting, thanks for sharing that
I had never thought about the relation between threads per inch and the strength of the fastening