Replacing
Boat Trailer Bunks with Roller Bunks, Using Common Tools
I have a friend, John Wicklund, who likes to
fish, but has had to downsize in his fishing machines
because he now lives in a retirement center with
covenants covering what he can park and where. He
did
purchase a Aluma Craft 14' aluminum Jon Boat, a 55-pound thrust Minn Kota, and an EZ
Loader trailer for fishing lowland
lakes for trout, Kokanee, perch, and bass.
The small trailer he purchased was apparently designed for
boats with gas motors attached, which would have been
heavier behind the axle than his electric trolling motor. The axle could not be
moved forward, so the tongue weight was more than he
liked. The trailer came with two 5-foot carpeted bunks
plus a small support toward the bow. Loading the boat
by himself onto those two bunks proved very
challenging for a older man with a replacement hip. He needed a much simpler and easier
arrangement.
He initially made up a plywood platform with
plastic “bunk slicks” and rear rollers attached, which
included extending the plywood 15" to the rear to try to
even out the tongue weight. As he explains below, this
worked much better than the carpeted bunks, but the
“bunk slicks” had shortcomings. It was apparent to him
that rollers were needed.
From the photos below, you can see that he is a
pretty accomplished engineer and carpenter, utilizing
wood that he can work with in his storage shed without
access to a welder to accomplish his goals.
Below are photos he supplied and his account of
what and why he did it.
Here was his early trailer configuration using the plastic/Nylon style bunk glides
"Just for the heck of it . . . . . . A recent
project.
When I bought a Jon boat and trailer a couple of
years ago, I quickly discovered that it was tough to
load the boat onto the trailer by myself. This cheap
version of an E-Z Loader trailer came with two 5-foot
carpeted bunks. Also, unfortunately the design of the
trailer is such that I cannot move the axle forward to
reduce tongue weight with a boat that does not have an
outboard motor on the transom.
I saw no need to submerge the trailer for
launching and retrieving a fairly light flat-bottom
boat, so I replaced the carpeted bunks with 8-foot 2X4s
with “bunk slicks” on them, plus a couple of rollers at
the back to help get the boat started up onto the “bunk
slicks” for reloading. To reduce tongue weight, I
extended the “slicks” and rollers about 15 inches beyond
the end of the trailer. And by moving the winch back,
the transom of the boat rested a good 12 inches beyond
those rollers. Tongue weight was still 125 pounds.
Well, those “slicks” were not very slick, and I
had to rub paraffin wax on them every time I launched.
Plus, the slicks in the rear were wearing down! With
more wear, the attaching screws would start scraping on
the hull.
So I bought 2 double sets of 4-foot roller bunks
from etrailer.com and installed them. They also stick
out 15 inches beyond the end of the trailer, and the
manufacturer would not guarantee them because of that.
Thus, I added 2 parallel 2X4s with a cross member bolted
under them at the back end.
When I would release the winch strap, I knew the
boat would quickly roll right off the rollers, so I
added a cleat on the winch stand for the bow rope to
temporarily hold the boat when the strap is released.
Each of the 4-foot roller assemblies weighs over
20 pounds, and I hoped they would not bend when I
winched the boat onto the trailer. Even if they did,
there is still a lot of support under the hull, much
more than with those original 5-foot carpeted bunks.
More detailed explanations:
1. The rollers are to support a 14-foot
flat-bottom Jon boat, with no weight of a gas motor on
the transom.
2. I saw no need to submerge the trailer to
unload or load the boat. Backing the wheels no more
than hub-deep in the water is all that is needed for
both unloading and loading.
3. I removed the two original 5-foot carpeted
wooden bunks and their brackets.
4. The curving shape of the trailer side rails
prevents moving the axle forward to better balance with
the motor-less, fairly light weight boat. To reduce
tongue weight, the boat needed to be positioned with the
transom a little over 2 feet behind the rear trailer
cross member.
5. I used four “U-bolts” (and lock nuts) to
attach 3/4 inch plywood to the two trailer cross
members. The plywood extends 15 inches beyond the rear
cross member.
6. The bottom of the boat hull has 5 ribs,
sticking down about 3/4”, with about 6 inches of flat
space between each rib.
7. Each of the four roller sets I purchased
from etrailer.com is 4 feet long. Each PAIR of rollers
sets is advertised as being able to support 2500
pounds. The triple roller assemblies are just under 5
inches wide, so they fit nicely between the hull ribs
and thus guide the hull straight onto the trailer.
8. I bolted the roller sets to the plywood,
flush with the back end of the plywood, and aligned
between the hull ribs. Lock nuts, of course.
9. The roller manufacturer would not guarantee
the roller sets against bending if they were extended
beyond support from the rear trailer cross member. So I
used “U-bolts” again to bolt a 2X4 parallel to each
8-foot roller assembly. Then I bolted a 2X4 underneath
the rear of those 2X4s, and thus under the end of the
plywood and the ends of the roller sets.
10. So, the “extended” roller sets have three
forms of support:
a. The steel channels themselves
b. The plywood
c. The 2X4 crossing underneath the
plywood.
If the steel channels do eventually bend a bit,
the rest of each 8-foot roller assembly still provides
much more hull support than the original 5-foot carpeted
bunks would have.
11. When loaded, the transom of the boat
extends about 12 inches past the rearmost rollers, and
the trailer balance is still rather tongue-heavy.
12. Knowing that when launching the boat it
would quickly roll off the trailer, I attached a cleat
to the winch stand to temporarily secure the bow rope
when I unhook the winch strap.
13. To load the boat, I attach the winch strap
and then move the boat out to the end of the trailer by
walking on the plywood or wading out. Then align the
rib spacing with the rear rollers and winch the boat on.
14. The trailer capacity far exceeds the weight
of the boat, and the torsion bar axle makes for plenty
of bounce on uneven surfaces. So I transport the
electric motor, battery, and gear in my truck rather
than in the boat.
15. The wood doesn’t get wet; when loaded, the
boat shields more than all of it from rain. And I don’t
submerge any of the wood at the launch ramp. (Note that
carpeted wooden bunks DO get wet when a typical bunk
trailer is submerged.)
Here e-trailer roller bunk units in 4' sections
You will
notice the cleat installed on the winch support to help
control the boat from sliding off the trailer too quickly
when unloading, after the winch line is disconnected.
Here is his later trailer configuration with the rollers
The trailer
rollers work perfectly! They reduce the effort
needed to crank the winch by about 70%, compared with
winching the boat onto those “bunk slicks.” And
the steel
channels show no evidence of bending".
The new trailer bunks being used to reload the boat
The photo above got my interest
in his removable modifications of outfitting this boat to
make it "Fishable", so I requested a few more
photos when he took
the boat out later. This platform unit is made
from plywood and bolted together, readily removable, since his
boat storage is in a open RV storage area on the retirement
center, he feels like he has to make all his attachments
readily removable and placed in his apartment when not in
use.
And the old brass rod holder brings back
memories to me, which he also has, it belonging to his
father. The two wooden rear cleats are used for a
second anchor when perch fishing if the wind is blowing to
keep the boat from swinging off the bow anchor.
Here is a closer look at John's OFFICE
In the photo below, you will have
to look hard to see just the rear end of 3/8" All-Thread
that he uses to clamp this platform onto the boat seat lips.
The "pole" is a removablebalance support
for him to use if standing to stretch his legs. You
can see the seat back is removable and from viewing it in
the above photo, made so it is angled outward at the top for
more comfortable seating.
And his tackle boxes are out of the way under the seat.
His "Christmas Tree" that he "C" clamps on the
Port side is the basis to attach the depth finder, a battery voltage meter
and a anchor rope cleat readily available from the OFFICE seat.
