Convert trailer from straight axle to drop axle

[bzano]

Just wondering if this is a worthwhile pursuit. I’m thinking of using a 4 in drop axle on my trailer for my Hunter 18.5. By lowering the trailer 4 in it would be helpful while setting up & rigging. Also easier to launch & retrieve. The clearance now is about 14 in from the frame to the ground so I should have plenty of clearance even if the trailer is lowered. Has anyone done this? Other than some $$ for the axle and some hours of work don’t see much downside. Thoughts?

 

[Project_Mayhem]

I can't comment on your proposed mod but here's some observations... There doesn't appear to be much weight on the front of the trailer. If you are having handling issues, you might want to consider moving the boat forward on the trailer.
I had a similar setup with a 19'. That thing had the same mini balloon tires and bounced all over the place

 

[Tedd]

In the photo, it looks to me like you might be a bit tight on ground clearance, but that could just be the perspective. So long as you're happy with the ground clearance I think it's a great idea. For a 9 degree ramp, getting the waterline 4" closer to the ground means the tow vehicle is about 25" further up the ramp when the boat floats off. Lowering the center of mass will improve stability, too, at least in theory. You might want to also lower your hitch ball so that the frame rails remain close to horizontal.

I recommend making four shoring stands to support the trailer while you're doing the work. I made some when I moved the axles longitudinally on my trailer and they were well worth the effort. I use them regularly for all sorts of things. The boat and trailer are back up on the shoring stands right now, while I'm doing the wheel bearings.

 

[Project_Mayhem]

Would the top of the ramp's concrete hit the trailer if lowered? I had this happen with a tongue extension. It can be addressed with an adjustable hitch but it's one more thing to do at the ramp. Rigging a sailboat takes long enough!

 

[Rick Webb]

Looks like a good idea to me on your trailer. 6" may even work.

Can't tell from the picture but if the axle were on top of the spring vs the bottom of the spring it would lower you somewhat and cost you may be nothing, or even very little to do.

Zero cost is assuming the axle bolt and U-bolts on the spring are easily removed. If it has locknuts on them, it is a good idea to replace those when removed.

Again, difficult to tell from the picture but putting smaller tires on the trailer could bring it down as well if you trailer long distances maybe switch them out for trips. A larger tire spins slower over the same distance traveled. An 8" tire spins like crazy at 60 mph. Don't skimp on weight ratings though.

 

[LLoyd B]

I can't see what you expect to gain by lowering the boat 4 inches while on the trailer. Have you considered platform shoes or stilts? Just going by the photo the biggest problem getting hull closer to ground is more one of depth of keel than wheel axle height. Nice boat bet it's fast

 

[Timm R Oday25]

The view from here ;
I wouldn't move the boat any further forward as the keel is already past the axle .
You want the axle to bear the weight ,not the trailer tongue .
When launching our boat , we usually make several trips up and down the boat .Trying to make as few possible .
Seems ,I'm always droping something onto the parking lot .
We've installed a ladder on the front of the trailers that helps both in going up onto the boat and when launching .
I really don't see what you might gain by going through all the work to lower your boat when you can't predict what you might run over !
I've dragged our trailer across more than one poorly angled ramp and driveway .