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Date: 13 November 2015. Welding Shop and a Riser.


It has been busy of late. As every boat owner knows there are always projects. Seaweed is over thirty years old. She has had more than her share of issues. The engine swaps (three engines in two years) has tested my patience, my happiness quotient and my sense of humor. Having a boat that cannot run is disheartening. Things are looking up and some progress is being made.

During hurricane season having a broken engine is more than a small worry. I was fortunate this year. That is not to say I did not worry myself sick at times. Seaweed is my home and when she is not mobile, I am not happy.

Plus too, I love to go swimming. There is something about anchoring in four feet of water and playing around in the water. Skipper gets to hang out on the swim platform. Sometimes she comes in with me. My First Mate likes both!


Background Information: As described in the Marinizing the Cooling System of a Tractor article, I have a lot going on in the newest engine's cooling system. Originally I did not have a heat exchanger and this stainless manifold was designed and made for me.


Built by
Tallahassee Welding and Machine Shop in Tallahassee, FL.

Let me explain what you're seeing. First of all, there's a heavy duty big stainless box that surrounds the pipes. Those pipes (RED ARROWS as seen above) carry the exhaust from the engine. Fluid, a combination of anti-freeze and fresh water, will fill said box. The solution will flow in from the bottom left corner and exit the top right. That water/anti-freeze concoction will go into (and come out of) a separate tank.

A sturdy stainless box encloses the Schedule 40 (heavy, thick walled stainless) 1.5" pipe. The STAINLESS PIPE carries hot exhaust air through the cooling manifold box. A NIPPLE at the top will deliver raw water into the pipe. That will further cool the exhaust.

The GREEN ARROWS AND STARS show water and antifreeze as they flow through the stainless box. There will be an external closed fresh water tank. That unit is a Heat Exchanger.



After the addition of a real heat exchanger into the system (thank you Steve) the stainless box essentially became redundant. It had become a stainless cooling manifold. The cooling will be handled by the heat exchanger.

I still needed to cool the exhaust gases. Single purpose risers have been on boats for decades performing just that task.

Todd in the office at Lizotte's Welding [phone: 727-343-7690] in St. Pete, FL

That is where Lizotte's Welding in St. Pete, FL came into play. I took by my stainless manifold and spoke with Todd. I wanted a riser. Inside that stainless box is my riser. We (meaning he) just has to get to it, and Todd's shop will do that for me.


Riser Primer


A riser is an important part of the cooling system for your motor. What happens is this: as your motor runs the exhaust gases inside get hot. Very, very HOT. Cars are the same and you know how hot your tailpipe can get!

On a boat we have something called a Riser. It is essentially a U-shaped pipe that the exhaust gases flow through, similar to your tailpipe.


Seawater is injected into the pipe after the hump. Placement is such that no salt water can flow back into your engine. The exhaust pipe aka riser has a nipple. Raw water from outside the boat enters the pipe just past the hump. The job of the raw water is to cool.

Note: on some risers the raw water completely encases the exhaust pipe. They are called water-jacketed. Water-jacketed risers will cool the exhaust just like mine does.


The riser is attached via hose clamps to a special (read "expensive") wire reinforced exhaust hose. After the riser my hose runs through a water muffler. From there another piece of exhaust hose is plumbed to exit the boat.

That is why you always see water coming out the exhaust pipes on boats. Outboards are the same. The water is a crucial part of the cooling the system.

Smart mariners always check their exhaust on start-up.

If no water is exiting, they immediately shut down the motor and find out why!


I needed a riser for Betsy, my Kubota 18hp engine. A few days after dropping off my stainless manifold (see photo above) Todd phoned. My riser was ready. The stainless surrounding it had been removed.

Side Note: I was charged for one hour.

I was happy to confirm the welds on the inside of the stainless manifold were a-okay.

Todd's shop (Lizotte's Welding) removed the exterior box. Another nice thing Lizotte did for me was mark where that smaller raw water pipe ends. It extends past the hump so there's no danger of water back-flowing into my engine.


I already knew exactly where the nipple/pipe ended. That's because I have this nifty tool called a Waterproof Borescope USB Snake Inspection Camera. A borescope is a cable about the size of 10 gauge wire with a small camera and lights at one end.


The camera part is 1/2" wide and about 2" long. There are six LEDs surrounding the camera. They are adjustable from Off to Bright. You plug into a USB port on your computer and voila: instant movie camera.

I loved that I could see what was on the inside of the stainless manifold prior to taking it to the welder. Because of the borescope I knew exactly where the water entered the exhaust pipe to cool off the gas too. 

Affiliate link

Waterproof Borescope


A borescope is an interesting tool. A friend uses one to
 check his prop for barnacle growth. It's waterproof.


Like many boaters, I have a thing for tools. My friend Doug once wrote:

"My wife says I claim to be messing with boats but that
what I am really doing is collecting tools." Douglas Pollard.

The nipple is quite long so attaching the raw water hose to it will be a breeze. This should cool my exhaust gases with ease. This is not the Whole Picture though.


Fiberglass Heat Shield Tape with Stainless Ties


LEDAUT 2" x 50' Titanium Exhaust Heat Wrap Roll for Motorcycle Fiberglass Heat Shield Tape with Stainless Ties

Many suggested to protect myself I needed to buy exhaust pipe heat wrap. The prices are all over the place on this stuff.

I purchased some heat shield tape on Amazon. It will be wrapped around the metal exhaust and will keep the pipe from burning me. A roll, 2" by 50' was $25.  

affiliate link


The saga continues. More upcoming when the process is completed. And that should be relatively soon. Knock teak.

I'd love to know if you've got your pipes wrapped.
And, did you use the same stuff or something else entirely?

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2015, 2023

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