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Discussion Starter #1
22’ NR Seahawk with the kicker mounted on the left side, on the small box style mount that is basically just welded onto the transom. Not connected at all the the offshore bracket. Have cracks in the welds at the top on both sides, figure too much pounding over the roads or waves over the years. Boat is 12 yrs old and run hard so not surprised I guess. Not extending down much at all and likely won’t fail ever, but I want it fixed soon.

Any recommendations for someone who can do a repair on it? I don’t weld aluminum at all so outside my skill level.

And once it is repaired- any thoughts on how to prevent it happening again? Aren’t there some supports struts or something that are made for supporting your motor when trailering? Do they help with this issue?
 

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Give Joe a holler, QuietRiot here on the board. He has a shop in St. Helens and does a lot of boat work. JD Aluminum Works.
 

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I think probably any of the boat manufacturers there could help you out or recommend someone. I’m assuming Motion Marine is still near there.
 

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Elite welding & Fab
Near clark county fairgrounds
Google search will give you info
 

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My Pro Steelheaader did same thing with a little 8 hp kicker: cracked at both upper welds. Been repaired twice so far, added gussets on second go-around. Gussets cracked even with superb welds by ex-aircraft aluminum fabricator. I need to figure out even more support/gusseting to add. So consider making some heavy duty mods to avoid the problem: don't just re-weld.
 

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Discussion Starter #7
Yeah it is a matter of stress concentration at those two small points, been thinking that over as well. Not a great design in my opinion (former Mech Engr/Designer of heavy equipment). You have a heavy object cantilevered out, that is going to get bounced around a lot, and they basically just welded an open box to it... not sure how I would have done it personally, but fairly certain not like they did it!

thanks for the recommendations everyone.
 

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Do you travel with your motor all the way down? If tilted up, not good.

fop
 

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Fop is correct. If I'm not mistaken I was corrected as well. Now the motor hangs, only up while moving on the water with the big motor. The travel position is down for me. No more bouncing..
 

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On the trailer I used a strap to snug the kicker down so it wouldn't flop and bounce going down the road. If you have ever followed a drift boat down the road with its motor unsecured you will readily understand why the mount is cracked.
 

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I travel with mine down. But upgraded gussets cracked.

I have driven behind and seen no bouncing. It rotates occasionally but that's about it. Been doing the snug strap to stop rotating.

Thought about adding a support off trailer frame but trailer design makes that impossible (would scrape on bumps).

Really scratching my head how to fix other than going to even larger gussets. Since Op is an ME, I will be quite interested to see what you design?

And no, I will not stop driving 95 mph in order to be the first person at the Fishin Hole. I have really perfected my 4 wheel drifts into the boat launch.
 
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T8s/T9.9s don't bounce on these brackets when tilted down. I've followed my own for probably a thousand miles with the wife towing it (I had the RV), and it probably has 150K total trailered miles in 15 years. Come to think of it, I've never heard of one of these NR brackets cracking.
 

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Since owning my seahawk i have been traveling with the kicker motor up... I checked the welds last night and didnt see any cracks or signs of cracks... When my motor is all the way down its only about a 15" from the ground... makes me feel uneasy.... so i tow with it up.....The 15" clearance bothers me.. but come to think about it my axel is probably lower than that...hmmmmm....
 

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Since owning my seahawk i have been traveling with the kicker motor up... I checked the welds last night and didnt see any cracks or signs of cracks... When my motor is all the way down its only about a 15" from the ground... makes me feel uneasy.... so i tow with it up.....The 15" clearance bothers me.. but come to think about it my axel is probably lower than that...hmmmmm....
Trailering with the kicker tilted up is not approved by Yamaha, unless a transom saver type device is used. I'd be more concerned about kicker damage from non approved transportation methods (unless of course you are using a transom saver).
 

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Discussion Starter #15 (Edited)
OP back here- always tow with the T8 kicker down. Lots of ground clearance. So not sure if the damage is from road travel, or blasting across waves and wakes at B10 and similar. I tend to go as fast as I can stand in rougher conditions, hate plowing along. Usually cruise at 30-35 MPH, boat will do high 40’s or even 50 MPH when it is really flat and going with the current! I adjust down as needed when rougher, basically go the same as most people do who have a little more power available than the average boat. 22 foot NR Seahawk with F250.

Certain the boat did not have this issue when I bought it used in 2009, but I suppose a prior owner could have towed it with the kicker up for the 3 yrs prior, causing the cracks to originate, though not be visible. The paint has been cracking for some time, I always put off doing a thorough inspection as it required breaking off a bunch of paint, and I could tell it was just the very top of the connection, and it did not appear to be worsening. Not sure if it is getting worse or not at this point since it has been a while since I looked at it. Just got looking at it again while replacing switches on the T8.

The main get one of the Yamaha spacer bumpers. So it gets towed as recommended by Yamaha.

If I had designed the boat it would be bullet proof. It would also require 2 or 3 F250 engines to do the work one F250 does now!

From an engineering point of view, just to consider the cantilever situation for say bounce and bump protection (motor not in use) the welds along the bottom of the kicker mount box don’t do much, the ones on the side don’t do much, and there is no connection and therefore no welds along the top. So any bouncing concentrates the downward force at the upper part of the side welds. Not surprised at all that they cracked really. If you towed with the motor up it would not be good as first the motor isn’t designed for that, and second you are increasing the arm on which the force is applied (moving center of gravity/force further away from the mount) so more torque = more damage to the weld joint at the top of the bracket connection.

as for gusset designs, I think the factory solution I would consider first would be to use much thicker side plates on the kicker bracket. That would give a larger weld foot print at the top while still maintaining the same look for the bracket. I would also likely over do it, and add a flat bar along the top of the inside of the bracket, making the weld now like 1 foot wide, instead of 1/2” wide combined like it is now. For a gusset fix, maybe 2” x 2” triangles, welded horizontally on the inside of the bracket to the top of the sides, to spread out the force. Then that force is applied to about 4-1/2” of weld vs the current 1/2” total. I sure would not bother with a vertical gusset, seems to be incorrect. Not very sure as actual experience and testing would be needed to really make that kicker mount bulletproof. It has been 25 years since I designed any machinery, and I never designed anything from aluminum, and in sawmill equipment, which was what I worked on, the answer was always to use 1/2” steel if you thought 1/4” was adequate! Or 1” steel if 1/2” was adequate!


for the member who added gussets- how big, where connected, and how were they oriented?
 
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