– Fixing Soft Spots or Delamination using Gorilla Glue or Foam Sealer

Gorilla Glue and Foam Sealer both expand when introduced into a void.  Gorilla Glue is especially water friendly and works in wet areas just fine.  In fact the more water the more foam it will create.  Gorilla glue dries harder and does not absorb water very easily.  Foam sealer is a little softer and will absorb water more easily.  In areas where water may get in again and where I need a very stable base beneath the fiberglass I use Gorilla Glue.  In areas that tend to stay dry and do not need as much support I use the foam sealer.

To fix soft spots with either Gorilla Glue or Foam Sealer you can follow these simple steps.

First, locate the soft spot and find its outer edges.  You can trace it out with a pencil if you wish.  If you have multiple spots just trace them all out at one time.

Second, drill holes using a drill no larger than a pencil.  The bit needs to be just large enough for the spout of the Gorilla Glue or Sealer nozzle to fit into.  The holes need to be all the way around the soft spot.   Say one every few inches. Also, put several in the center of the spot.  The extra holes will give the foam a place to escape.  One hole may not be sufficient. I use a very short drill bit so I do not go through the other side of the boat.

Third, squeeze in the Gorilla Glue or Sealer.  Fill each hole.  If you fill one hole and the glue comes out other holes that is good.  You will need to force the glue into the void.

Fourth, place a weight on the area.  This will keep the glue from bowing the surface.  I have done areas and not used a weight with no problems but it is better to be safe.  I use a concrete block and tip it on its edge.  This way it is easier to remove.  If you lay it flat you will glue it to the boat and will not be able to easily get it off.

Fifth, let the glue dry, expand, foam, etc..  It will come out of the holes quite a bit if the area was wet.  I normally wait a few hours or overnight.

Sixth, remove the weight and scrape the excess Glue off with a putty knife or any flat blade.  The grind away any excess until you are back down to the bare fiberglass and holes.

Seventh, take a drill bit or steel rod and put it into the hole and make a void right at the surface down just a fraction.  Do this for all the holes.  Then take a disc sander and hit each hole so it becomes a little divit.  Just slightly.  The idea with this step is to give the epoxy you are going to use a place to bond both inside and outside the holes.

Eighth, mix epoxy or use the epoxy in the syringe and force it into all the holes.  Fill them all the way to the top.  Then let the epoxy set up until it is completely hard.

Ninth, once the epoxy is hard, grind the area down smooth.  If the area is in a place that you feel needs more reinforcement then sand the area, apply some epoxy and fiberglass cloth and let it set up.

After you have completed these steps you can paint the area.

Foam goes in one hole and will normally come out multiple holes.  Use the type of foam that is designed NOT to bow or distort.  It is normally in the blue can.  The other type which is normally in a red can and called Great Stuff may bulge the hull.  I have found the blue can type to be safer.  Also, I have had no problems with the Gorilla glue bowing the hull.  After I filled the holes with foam I reamed out the hole and forced in epoxy. Then I sanded the area and applied a layer of west epoxy with the collodial silica thickener in it.  If there were cracks or weak areas I added some fiberglass cloth to the repair.  Then I painted the area with polyurethane topsides paint.

– Fixing or Repairing Small Dings and Holes in a Boat Hull

Repairing dings and holes in the hull of your Boston Whaler 13, 15, 17 or larger boat is not as difficult as you would think.  Especially if the hole has not caused any delamination between the hull and the foam.  The steps to fixing a simple ding or small hole are as follows.

First sand the area.  I use a disc sander.  You want to create a rough area around the hole or ding for epoxy to stick to.

Next you will fill the hole or ding with epoxy that has been thickened with colloidal silica.  This is simply a filler that you add to epoxy to give it more substance.  West Epoxy systems carry this.  I normally mix my epoxy and hardener together and then immediately stir in the colloidal silica.  You have about 15 minutes to use the epoxy so you need to get it thickened quickly.  Once mixed you simply take a bondo spreader and putty into and around the ding or small hole.  Spread it onto the roughened area around the ding as well.  Get it as smooth as you can.  Note – you can also use Marine-Tex.

Now you are going to take a vibrating sander and smooth out the area.  You can use a medium grit and then switch over to a finer grit.  If you need to you can mix some more epoxy and spread a thin coat to fill in any imperfections.  Then sand again until it is perfectly smooth.

After the area is smooth you just wipe it down with a solvent thinner and paint the area with a topside paint.

For larger holes see our article to the right.

– Fixing or Repairing Larger Holes in your Boats Hull

Repairing larger holes in your Boston Whaler hull can be a little more involved than small dings, however, the process is still relatively simple.

First you are going to sand or grind into the hole which is actually going to make it bigger.  Sand or grind away until the edges are clear and then sand all the way around the hole.  For a Boston Whaler you also want to create a void behind the hole.  To do this you can sand away or scrape away some of the foam so that the fiberglass is exposed inside and out.  The idea is to be able to fiberglass the inside and outside of the damaged area for maximum strength.  Before the next step you need to make sure the damaged area is very dry inside and out so that the epoxy will adhere.

I normally mix a batch of West Epoxy and then chop up some fiberglass cloth and mix that into the epoxy.  It makes sort of a mush.  It may not be pretty but it will make the repair strong.  After I mix and create a mushy mixture of epoxy and cloth I push it into the hole so that it presses against the back of the hole all the way around and basically fills in the hole.  You can use a stick or a screwdriver to push it into the void.  You want to fill the hole up with this mixture.  Then just let it set up.

After the epoxy mush sets up you should be left with a hole that is filled in but still very rough looking.  To smooth out the hole just take some epoxy, thicken it with colloidal silica and spread it into the hole until it is smooth.  Then you can cut some fiberglass cloth that is a little larger than the hole, mix epoxy, coat the hole and the surrounding area, lay the cloth on, coat it again and let it set up.

Then just sand the area smooth and paint it.  That’s all there is too creating a very strong fiberglass repair that is actually stronger than it was before it was damaged.


– Removing Water from a Boston Whaler Hull – Foam Waterlogged

The foam in a Boston Whaler is a closed cell type foam and always has been.  This means it does not readily absorb water.  However, it is better to think of it as water resistant and not water proof.  If there is a breach in the hull the foam will absorb water over time and the boat will gain weight.  This is especially a problem if the boat stays in the water and there is a crack below the waterline.  Or if the breach is inside the boat towards the back where water sits. In any event, if you find that your boat is way overweight then the only explanation is water in the foam.

Removing water from the foam is fairly simple and can be done via gravity or suction.  To remove water you are going to need to drill more holes.   Most people are hesitant to drill holes in a boat but since it is fiberglass, filling the holes back in permanently is not a big deal.  On the boat that I restored we removed water using two methods.  First, when the boat was upside down I drilled out  a large hole on each side of the boat.  The holes were next to the rub rail but since the boat was inverted they were at the bottom.  (see picture below)

As you can see I attached a shop vac to the hole.  Then I let it run for hours and hours.  I did this on both sides. This pulls a vacuum and drys out a large area of the foam. After I removed all the water that I could I filled the void with Gorilla Glue and taped off the hole to hold the glue in.  When it was dry I made a void and filled the area with epoxy inside and out.  Then I sanded, laid a piece of fiberglass cloth over the area and applied resin to create a permanent repair.

The second way I removed water was to put the boat at an angle like the picture above and drill some small holes at the lowest point in the rear of the boat.  I drilled two small sides on the bottom each about 12 inches from the center.  I let the boat drip for a few days and then dried the hole with a wet vac, made a void with a drill bit and then filled the holes with gorilla glue.  Then I made a void in the gorilla glue and filled with epoxy.  Then I sanded and smoothed on some West System epoxy.  The holes were small so no fiberglass cloth was needed.  When winter comes I may drill a couple of holes and let it drip all winter. Every little bit helps lighten the boat.

(Note – One thing to remember is to never pressurize the hull by blowing air into it.  This will cause all the foam to separate from the fiberglass.)

– Replacement Mahogany Seats Boston Whaler Classic 13 Footer

Replacing or Restoring your Classic Boston Whaler 13 Footers Seats and Interior Wood.

Once you are finished fixing soft spots, filling dings, glassing cracks, replacing hardware, etc… you are going to need to decide whether to refinish or replace your seats.  As a general rule of thumb if your seats are warped then replace them.  If they are straight then you can refinish them.

To refinish mahogany seats you simply need to sand and strip them and apply a few coats of exterior varnish.  A liquid stripper is fine and should be followed up with a good sanding.  If you wish you can stain the wood but since it is mahogany the wood will be beautiful in its natural state.  Make sure to use the spar type varnish / urethane that is made for outdoor applications. (see picture) The indoor polyurethane will only last a short while in a salt and sun environment.

If you choose to replace your seats you can get them from www.specialtymarine.com .  Their prices are good and they deliver quickly.  I had mine in just a few days.  I chose to replace mine since they were warped and had holes drilled everywhere.  I bought all the wood including the side panels for less than $500.

When you replace all the wood in the boat you are going to want to make sure the holes that you screw into are able to hold a screw.  Oftentimes the screw holes become stripped which is common with fiberglass.  Before I put my seats in I filled all the previous holes with epoxy.  Once the epoxy was set I redrilled small tap holes and installed the wood.  Also, I squeezed in some 3m 5200 to waterproof the hole.  This is mostly common sense but worth mentioning.

– Minimum / Maximum Engine Size for a Boston Whaler 13 Foot Classic

There has been a lot of discussion about what size engine is needed on the 13 foot classic Boston Whaler.  The boats intended use has a lot to do with this answer. In all cases below, a hydrofoil such as a Davis Doel Fin, an SE Sport Stabilizer or a Stingray Hydrofoil will help the boat achieve a plane and operate more efficiently.  Especially in rough water.

Lets first start with the absolute minimum engine needed to plane the boat.  This is going to vary between a 9.9 horsepower and a 15 horsepower motor.  A lightweight Whaler with a lightweight person aboard can possible achieve a plane with a 9.9 horse motor.  And as stated above, a hydro foil will help.  If the boat has more than one person aboard or is heavier because of water intrusion then this will not be enough horsepower.

A 15 horsepower outboard will more easily achieve a plane even with more than one person in the boat.  The top speed will be around 15 – 17 miles per hour.  If you intend on pulling a wake board or skier you will probably be disappointed in performance.  For a single person who uses the boat for fishing a 15 is going to be sufficient.  Your gas mileage will be great and you will be able to troll at slow speeds very well as well as get up on a plane and get home on time.

A 20 horsepower motor is the minimum that you will need if you want to carry several people at one time and want to pull wake boards or kids on water skis.  It will get onto a plane very easily and travel about 20 – 25 miles per hour.  Gas mileage will still be great and trolling still nice and slow.  We have a 20 horsepower Tohatsu with electric start and tilt on ours.  It is great for the kids because it does not go too fast but its still fun and feels like your flying even though you are only going about 20.

As you go up from a 20 horsepower you will no doubt want to switch from a tiller steer motor to a steering wheel.  As a general rule of thumb you get about a mile per hour from each horsepower.  A 20 hp will do 20, a 25 will do 25, a 35 will do 35 mph and so on.

A 40 horsepower motor is the largest that I would recommend for the boat.  It will carry you along at about 40 miles per hour and will put almost any size skier.  You would need to be careful traveling at high speeds in rough water.  A motor this size is not recommended for kids or beginners.  Keep them in slower boats for their own safety.

A motor larger than a 40 becomes dangerous for several reasons.  First it is too heavy for a 13 foot boat.  On a classic pre 1972 boat the transom would almost be under water at idle.   Second, it will make the boat go too fast.  13 foot boats do not need to be going 50 miles per hour.  A dive into a wave can easily throw everyone off the boat.  Also, a quick turn can flip the boat.  Going fast in a boat is fine but it needs to be done in a longer more stable boat.   For the 13 foot classic Boston Whaler stick with a 40 horse or below.



– Boston Whaler Tohatsu 20 HP Outboard with Sport 200 300 Hydro Foil Review

The Boston Whaler and the outboard motor have been an almost perfect match since the inception of the boat.  This is mainly due to the wide stern and seaworthy hull design.  You get a safe feeling in a Whaler that you don’t get with other designs.  When your kids go out in a Whaler you don’t worry quite as much. There are, however, some issues that if corrected would make the boat even safer and more enjoyable.  Especially in heavy seas. These issues center around the outboard motor.

An outboard sits at the very back of a boat which is where the operator, fuel supply and battery are as well.  This creates a boat that is back heavy.  On longer boats this is not as much of an issue but on 13 and 15 footers it is.

One of the issues with a short boat that is back heavy is the tendency of the bow to rise excessively during planing.  In heavy seas this can create an uncomfortable situation for the operator. When running into the wind it feels like you will flip over backwards.  Also, when slowing down the boat tends to want to come off of a plane quicker and the bow goes back up.  In heavy seas you often want to slow the boat down but not to the point where you come off of a plane.

Another issue for boats that are underpowered is the time it takes to get onto a plane.  In some situations the motor is not able to do this at all.  For example, a 13 foot Boston Whaler with a 9.9 horse engine will barely get onto a plane if at all.

Short boats in heavy seas tend to get tossed around quite a bit.  On longer boats in excess of 17 feet this is not as noticeable. Although this cannot be eliminated, it can be reduced.

I installed an SE 200 Hydro Foil on my 13 foot Boston Whaler Sport and noted the following improvements –

  • The foils provided lift and keep the bow of my boat down during planing.
  • They also make my boat plane much quicker.  The bow stays down. (It is my understanding that on a 13 foot whaler with a 9.9 hp motor you can get onto a plane with a foil installed.)
  • The boat remains on a plane at much lower speeds which is great in rough seas. This is probably the best feature.  When it gets rough I have a wide range of speeds that I can choose from.  Before, I only had full speed and idle because when I slowed a little the bow would rise and the boat would get tossed around.
  • The fins seem to stabilize the boat as well.  This is also true when we tow it provided the motor is left down. The effect is similar to a gyroscope.
  • The SE Hydro Foil seems to reduce cavitation.

There are several fins available and they all work in generally the same way.  Some provide more lift than others.  Some are two piece and some are one piece.

I have a video at the following link that show my boat planing.  You will notice that the bow stays almost level the entire time. Boston Whaler 13 with Tohatsu 20 Horsepower and Hyrofoil Planing

It is my opinion that the foils or stabilizers work best on smaller boats.  The reason is that larger boats simply do not have the same issues to correct.  Also, you will see where people claim it makes the boat go faster.  I have not seen a noticeable difference.  If anything it may knock a half a mile per hour off your speed.  It really depends on whether the stabilizer remains underwater at full speed.

Here is a list of stabilizers.

Sport Marine SE 200 Hydro Foil

Sport Marine SE 300 Hydro Foil

Davis DOEL Fin

Stingray Speed XP

Stingray Junior

Seasense Outboard Motor Foil



– Boston Whaler 13 Sport Planing Out with 20 HP Outboard

This is a video of my 13 foot Boston Whaler planing out.  It has a 2011 – 20 horsepower Tohatsu outboard with power tilt and electric start.  I added an SE Sport Hydro Foil to the engine which also helps in faster planing.  You will notice that the nose stays down while accelerating.  This is due to the Hydro Foil.  The Tohatsu motor  cost around $3,200 via the online outboards website.  A 20 horsepower is the largest engine that they will ship.  Larger engines have to be installed at their location.  This is the main reason I went with a 20 horse versus a little larger engine.  I am very pleased with the performance of the boat and would recommend this setup to anyone.  We have had 4 adults in the boat and were still able to plane quickly and run about 20 miles per hour.

The purpose of this video is to visibly show that a 20 horsepower motor will plane out a 13 foot Boston Whaler very easily.

– Boston Whaler 13 15 17 Bimini Top Installation and Review

A bimini top accomplishes a variety of goals. First, it keeps you out of the sun and reduces your chances of sun burn.  Second, it keeps you cool in the shade.  Third, it keeps you out of the rain.  For long days on the water it is a must have item.  After we restored my 1967 Boston Whaler Sport 13 the first thing I ordered was the Bimini Top.  I purchased mine from www.specialtymarine.com .  They carry everything for the Boston Whaler and I felt like I would get the best fit buying a top made for my model boat.  The cost was $389.00.  The model I purchased fits the Boston Whaler 13, 15 and 17 foot models.

It took me approximately an hour and a half to install.  I had to figure out where all the poles went together and then had to screw the fittings on.  The instructions are good and all the parts I needed were included.  Once I had the canvas on the frame I measured the boat width and pulled the two arms of the top together so that the width of the boat and the width of the brackets would match.  After a few tries I got a match.  If you don’t bend the arms and match the width of the boat the top will always be pulling against the brackets from side to side.

I then positioned the bimini where I wanted it to go and marked the position of the main brackets. You should be able to keep the back and middle seat covered if the bimini is positioned right.  I kept the brackets as close to the outside edge as possible because I wanted to drill all the way through and use washers on the ends of the bolts.  (If you just screw into the thin fiberglass with a wood type screw the brackets will work their way loose and the top will eventually come off.)  I drilled through, filled the hole with 3m 5200, pushed the screws through the brackets and the holes and then put a washer and nut on the bottom side.  After the top was mounted I positioned the strap brackets and did the same.  The rear brackets are mounted to the transom so on those I was able to get a strong hold using stainless wood type screws.  Again, every hole was first filled with the 3m 5200.  After everything was tightened up I was done.  There are some stainless arms that can be used along with the straps but I did not really need the extra strength.  My boat only goes about 20 mph. 

I have to say that I am very pleased with the quality of the top.  Everything is stainless.  The fabric is a nice marine canvas with a vinyl backing to make it waterproof.  It is not as thick as I thought it would be but it is fine.  I have a spray dodger and sail cover on my sailboat and that material is thicker.

Note – When you install the top make sure to tighten up all the allen screws.  They are the ones that hold the stainless tube in the brackets.  If you don’t tighten them the top will jump out of the bracket in rough seas.  Also, keep the right size allen wrench on board just in case.


Installing Reflective Striping to make your Boston Whaler more Visible

Installing reflective striping along the top edge of your Boston Whaler will make you and your boat much more visible to marine traffic. Also, when being trailered the tape makes you visible to automobile and truck traffic. Imagine having your beautiful little Whaler parked in a lot and having someone turn the corner and head right for your boat and trailer. A simple strip of reflective tape would make your rig visible to even the most distracted driver.

There are several choices for tape. The least expensive and most versatile is going to be a flexible engineer grade. It comes in the most colors and is perfect for marine applications since it is only one layer and will not delaminate. A 1 or 2 inch roll is all you need.  This material is very flexible and easy to get to conform to curves.  It feels the same as what electrical tape would feel like.  Only very bright and reflective.

A second and even brighter choice would be a V82 Oralite tape.  It is going to be about 8 times brighter than engineer grade.  Since it will not stretch it would need to be applied to a flat, smooth surface.  V82 is just like a SOLAS tape but in colors.

Both of these tapes are a single layer design and will not delaminate making them perfect for marine environments.