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Installing Seat Risers and Seats
Seat risers and plank seats are typical for boats like the freighter canoes and the
Adirondacks Guide Boat.
This is a much simpler operation than you may think however the steps are important.
Installing seats in your boat accomplishes more than just giving you a place to sit. In
most cases it also helps to pull the boat together from side to side. Basically it acts as
a thwart, and as such requires good tight connections minimizing the mechanical
stresses associated with the forces pushing down on the seat, (namely your tush) as
well as the forces acting to push the sides of the hull outward.
Adirondacks Guide Boat.
This is a much simpler operation than you may think however the steps are important.
Installing seats in your boat accomplishes more than just giving you a place to sit. In
most cases it also helps to pull the boat together from side to side. Basically it acts as
a thwart, and as such requires good tight connections minimizing the mechanical
stresses associated with the forces pushing down on the seat, (namely your tush) as
well as the forces acting to push the sides of the hull outward.
Preparing the Seat Risers
The first and probably the most important step is lining out where the seat will be. the method of doing this will vary from boat
to boat. On some designs it is easier to measure up from the floor of the boat or the bottom of the hull and others make it
easier to measure down from the gunwale. Most plans will give recommended seating positions and heights. When
measuring for the placement of the seats, be sure to take into consideration the thickness of the seat blanks, risers and so
forth to ensure the seat height actually ends up where you intended it to be. It is helpful to measure from as many positions
as you can. Presumably your boat hull is symmetrical about the centerline. This means that you can measure from the stem
to each edge of the set to ensure that the seat riser is in the same position on both sides of the hull. By having the seat riser
slightly shorter than the seat width means you can be off by a little without worrying too much.
The first and probably the most important step is lining out where the seat will be. the method of doing this will vary from boat
to boat. On some designs it is easier to measure up from the floor of the boat or the bottom of the hull and others make it
easier to measure down from the gunwale. Most plans will give recommended seating positions and heights. When
measuring for the placement of the seats, be sure to take into consideration the thickness of the seat blanks, risers and so
forth to ensure the seat height actually ends up where you intended it to be. It is helpful to measure from as many positions
as you can. Presumably your boat hull is symmetrical about the centerline. This means that you can measure from the stem
to each edge of the set to ensure that the seat riser is in the same position on both sides of the hull. By having the seat riser
slightly shorter than the seat width means you can be off by a little without worrying too much.
Once you are convinced that your seat locations are properly marked, it is time to cut and fit
couple of inches shorter than the depth of your seat. For example, if you seat blank is a 10"
wide Ash plank, then your riser would be about 8" long. A typical seat riser blank for a canoe
or small rowing boat would be about 3/4" X 3/4" X 8". There is nothing critical about these
measurements other than making sure that the resulting riser has enough meat to it to take a
screw and support the seat.
Once the seat riser is cut to length, you need to plane, sand or otherwise shape one side of the
blank to match the profile of the hull. There is no right way or wrong way to do this, use the
tools you are comfortable with. A simple way to accomplish this is with a simple compass and
scrap of 1/4" plywood. Scribing takes a few seconds and is very accurate. Place the scrap of
plywood against the hull at the riser location and run the compass along the hull putting a line
on the plywood following the profile of the hull. Cut with a jigsaw or sand with a stationary
sander. Make as many passes as necessary to get your final profile then simply transfer it to
the seat riser. Once this profile is transferred to the riser you can plane or sand off the excess
material giving you a perfect fit. The riser on both sides of the hull should be the same (at least
in theory).
couple of inches shorter than the depth of your seat. For example, if you seat blank is a 10"
wide Ash plank, then your riser would be about 8" long. A typical seat riser blank for a canoe
or small rowing boat would be about 3/4" X 3/4" X 8". There is nothing critical about these
measurements other than making sure that the resulting riser has enough meat to it to take a
screw and support the seat.
Once the seat riser is cut to length, you need to plane, sand or otherwise shape one side of the
blank to match the profile of the hull. There is no right way or wrong way to do this, use the
tools you are comfortable with. A simple way to accomplish this is with a simple compass and
scrap of 1/4" plywood. Scribing takes a few seconds and is very accurate. Place the scrap of
plywood against the hull at the riser location and run the compass along the hull putting a line
on the plywood following the profile of the hull. Cut with a jigsaw or sand with a stationary
sander. Make as many passes as necessary to get your final profile then simply transfer it to
the seat riser. Once this profile is transferred to the riser you can plane or sand off the excess
material giving you a perfect fit. The riser on both sides of the hull should be the same (at least
in theory).
Applying the Seat Risers
If you are following along, you should now have seat risers cut and beveled to fit as well as a clearly marked locations for
your seats. The next step is to get the risers stuck to the side of the hull. Thank God for modern technology. There are a
number of "rapid cure" epoxies available which dry in less than 5 minutes, so make sure you have a soda (or any of your
other favorite libations) within reach. Carefully following the epoxy instructions, mix and spread to the riser. Place the riser
to the hull and start drinking, hum your favorite tune or otherwise amuse yourself for the next 3 minutes or so (follow the
If you are following along, you should now have seat risers cut and beveled to fit as well as a clearly marked locations for
your seats. The next step is to get the risers stuck to the side of the hull. Thank God for modern technology. There are a
number of "rapid cure" epoxies available which dry in less than 5 minutes, so make sure you have a soda (or any of your
other favorite libations) within reach. Carefully following the epoxy instructions, mix and spread to the riser. Place the riser
to the hull and start drinking, hum your favorite tune or otherwise amuse yourself for the next 3 minutes or so (follow the
Now that the risers are in place it is time to reinforce them. This is easily accomplished with a
application of a fillet, pronounced (fill-let) and glass tape both above and below the riser. Take the time
to do this neatly, it will save you a lot of clean up time. Using epoxy and wood flour makes a fillet which
is not only structural but blends well with a wooden boat. Using other fillers such as micro-balloons will
do the trick but in my opinion they are unsightly. For a fillet of the size you need here a plastic picnic
spoon works well. The primary purpose of the fillet in this instance is to round over the edges in
preparation of the fiberglass tape. Using blue painters tape to tape off the area before the fillet is
applied will save in clean up time and make for a cleaner job.
application of a fillet, pronounced (fill-let) and glass tape both above and below the riser. Take the time
to do this neatly, it will save you a lot of clean up time. Using epoxy and wood flour makes a fillet which
is not only structural but blends well with a wooden boat. Using other fillers such as micro-balloons will
do the trick but in my opinion they are unsightly. For a fillet of the size you need here a plastic picnic
spoon works well. The primary purpose of the fillet in this instance is to round over the edges in
preparation of the fiberglass tape. Using blue painters tape to tape off the area before the fillet is
applied will save in clean up time and make for a cleaner job.
Once your fillet is in place and dry to the point it will not move when touched, you can apply the
fiberglass tape. Above the riser, keep the tape on the hull the same size as the seat blank and it
will be invisible when the job is done. For the purpose of symmetry ( I am a bit obsessive), make
the tape below the riser the same dimensions as the tape above. You will want to give the glass
tape a few days to dry before finishing off. Where there was tape, you should be able to cut away
the excess with a sharp razor knife. A little hand sanding and touch up with clear epoxy or spar
varnish will blend the edges.
fiberglass tape. Above the riser, keep the tape on the hull the same size as the seat blank and it
will be invisible when the job is done. For the purpose of symmetry ( I am a bit obsessive), make
the tape below the riser the same dimensions as the tape above. You will want to give the glass
tape a few days to dry before finishing off. Where there was tape, you should be able to cut away
the excess with a sharp razor knife. A little hand sanding and touch up with clear epoxy or spar
varnish will blend the edges.
This step is a test of patience. The natural inclination is to go for the win on the first cut of the seat. this will generally end
up with a loose fit. The reality is this is an unforgivable mistake. Pretty much all wood strip hulls naturally flex inward when
taken off the molds. This means to get them back to their intended shape you need to flex the hull back out. So unless
you are a wizard with jigs, this is definitely a job for two. Spread the hull with a temporary thwart and use the same scribing
method described above to make a template for where the seat meets the hull. Once you have that profile down, it is a
simple matter of getting the length right. Best rule of thumb here is to remember that you can always take more off but it is
very difficult to put it back on. You only need to get it within an eighth of an inch or so because when you take out the
temporary thwart, the hull will spring back tight against the seat.
***** Important to remember*****
Do not permanently install any of the seats before you have all seats fitted or you will not be
able to spread the hull.
If you are working on a hull where you won't be pounding the waves or have a good deal of
stress on the seats, you can install the seats with screws move on to the seat post. If you
think there will be some bouncing around, you should consider putting a fillet and glass tape
above the seat after setting the seat in a bed of epoxy mixed with wood flour between the
seat and seat riser. This is the best way to install the seat but it is also a very permanent
way of installing the seat. The only conceivable downside to this type of permanent
installation is the ability to replace the seat or the occasional sanding and varnishing of the
underside. Let's face it, how often are you really going to do that? Now that we both agree
that you won't be varnishing the underside of the seat often enough to make a difference,
we can also agree that the only downside is if repair is necessary. Repair can still be made
if necessary (which is not very likely), but it will take patience and some good shop tools to
grind out the connection of the seat and risers.
Do not permanently install any of the seats before you have all seats fitted or you will not be
able to spread the hull.
If you are working on a hull where you won't be pounding the waves or have a good deal of
stress on the seats, you can install the seats with screws move on to the seat post. If you
think there will be some bouncing around, you should consider putting a fillet and glass tape
above the seat after setting the seat in a bed of epoxy mixed with wood flour between the
seat and seat riser. This is the best way to install the seat but it is also a very permanent
way of installing the seat. The only conceivable downside to this type of permanent
installation is the ability to replace the seat or the occasional sanding and varnishing of the
underside. Let's face it, how often are you really going to do that? Now that we both agree
that you won't be varnishing the underside of the seat often enough to make a difference,
we can also agree that the only downside is if repair is necessary. Repair can still be made
if necessary (which is not very likely), but it will take patience and some good shop tools to
grind out the connection of the seat and risers.
don't have them, go and get them. You don't want to have come this far and crack the seat
blank for lack of a $5 item. In order to make a neat job of it, use the compass and scribe a
line in 1/2" from the hull along the seat so that your screws follow the hull line. If you are
using brass screws you can flush mount them and varnish them over. If not, you, you can
When putting screws down from the seat to the riser countersinking is not an option so if you
purchase bungs (or plugs) and fill the screw holes. If you want to make decorative bungs
from wood such as Purple Heart or Mahogany, you can purchase bung cutters for just a few
dollars and it makes for a dramatic look.
Installing the seat posts
Seat posts are exactly what you think they are. Posts that connect under the seat to the bottom of
the boat. These can be a simple as a blank cut from the same stock as the seat or as ornate as a
blank for lack of a $5 item. In order to make a neat job of it, use the compass and scribe a
line in 1/2" from the hull along the seat so that your screws follow the hull line. If you are
using brass screws you can flush mount them and varnish them over. If not, you, you can
When putting screws down from the seat to the riser countersinking is not an option so if you
purchase bungs (or plugs) and fill the screw holes. If you want to make decorative bungs
from wood such as Purple Heart or Mahogany, you can purchase bung cutters for just a few
dollars and it makes for a dramatic look.
Installing the seat posts
Seat posts are exactly what you think they are. Posts that connect under the seat to the bottom of
the boat. These can be a simple as a blank cut from the same stock as the seat or as ornate as a
turned style. These are attached using the same methods you used to attach the
seat risers to the hull. The only difference is the tape job. In connecting the seat post to
the hull, you may want to consider three layers of tape in progressively larger widths. For
the sake of argument, start with a 1" piece of fiberglass tape, progress to a 2" then a 3"
piece to top it off. You don't want to have to deal with a lot of stray epoxy and glass
strands so tape off the area at each application so that the edges can be clean and
straight. If you use this same method on the connection from the post to the seat blank,
you will eliminate the need for any mechanical fasteners through the seat to the post.
And there you have it. Sizes and shape will vary from boat to boat but the theory remains
the same.
seat risers to the hull. The only difference is the tape job. In connecting the seat post to
the hull, you may want to consider three layers of tape in progressively larger widths. For
the sake of argument, start with a 1" piece of fiberglass tape, progress to a 2" then a 3"
piece to top it off. You don't want to have to deal with a lot of stray epoxy and glass
strands so tape off the area at each application so that the edges can be clean and
straight. If you use this same method on the connection from the post to the seat blank,
you will eliminate the need for any mechanical fasteners through the seat to the post.
And there you have it. Sizes and shape will vary from boat to boat but the theory remains
the same.
