Archive for the Boat Mods Category

Update on the Sailboat motor progress, VOLVO MB10A is ALIVE!

Posted in Boat Mods on January 22, 2010 by chrischow

Step one, put it all back together.
Step two, don’t actually put it all together, test what you got with a can of Ether and jumper cables. CHECK!
Step three, put the manifold on and have it idle on the first start! BINGO

Next up, figure out if I need to get a new charing regulator. This motor uses a DC motor for staring and generating. I’m not too sure whats going on in the starter/generator unit. But it is called Dynastart and I think it was made by Bosch. I’m not sure if the windings for the two systems are shared in any way. I dono. Im confidint that its not too too wakey. In fact I think a VW bettle regulator would fit it fine. There are some nice solid state units available too. Here’s one I found today.

First page I found talking about a solid state bosch charing regulator for ‘dynamos’

A place that sells em’

Again, I’m not perfectly clear on what the proper way to switch around the power for the starting side and the charging side. This weekend will be electric.

Spanish instructions for ^^ that


This blog needs more boat

Posted in Boat Mods with tags , , , , , , , , on June 22, 2009 by chrischow

So true, perhaps If I had an oil resistant keyboard at my “boat yard” (thanks Zach’s parents) This kinda writing might be easier. Nevertheless, heres an update on S/V RonTom the 1976 Irwin 10/4 I own. (note to self. publish that post about the epic voyage getting the sailboat already!)

After many weeks of searching on the CL and other parts of the Interwebs, I have finally found a replacement inboard motor for RonTom. So, its not exactly a drop-in replacement. But, more like a parts motor for that will be part of a franken-motor that will be re-powering my beamy beast.

The original auxiliary motor was a Volvo MB-10A heres some technical stats on it: yea, stolen from

Technical data
Engine MB10A
Production period 1971-1977
Operation 4-stroke
Cylinder configuration 2
Bore (in.) 3.5
Stroke (in.) 3.23
Compression ratio 6.5:1
Displacement (cu. in.) 62
Power (hp) 15
Max engine speed (rpm) 2000

Sweeettt 2000 RPM! The drive to North Carolina to pick up the motor was a bit torturous. My friend Bill and I drove my car with the ol’ Harbor Freight Trailer. One Sunday night and arrived in New Bern about 12 hours later. What? That doesn’t sound that bad? We’ll it wasn’t really, but All of Georgia was fog and then it rained most of the drive up. Then we passed South of the Border but had no time to stop! Oh my! The drive back home was not as complex. But both of us were pretty wrecked from being up for more than 24+ hours.

I found the motor on a random seaching of the google just on a whim. I was probably thinking that some hot new news about the MB10a was going to hit some blogs or something. Well I found one person on a sailing forum (can’t remember the name) that had a post with a link to a craigslist ad for a used mb10a. Cha Ching!

Heres a video of what the motor looks like running.

Again, those are not my videos. I wish! I got pictures tho!
Currently, I have been taking apart and cleaning rust. Lots of Phosphoric Acid dipping… Stay tuned for updates on the motor rebuild and the eventual repower of the Irwin.

Spraying Gelcoat, done with gun mods, its time to spray the rudders.

Posted in Boat Mods on October 26, 2006 by chrischow

So I made those modifications to the spray gun and WHAT A CHANGE. I simply drilled the nozzle tip with a 5/64 drill, which turns out to be around 2.0mm and added an 1/8″ shim to the trigger system to allow the needle valve to get more displacement of the valve.

Last night I shot two small 7 oz batches with this “new” gun. I used styrene and wax and catalyzed like normal. At first, more styrene seemed to have a positive effect on the orange peel, I used 10cc first, then tried 15cc. But after about 15 minutes, both rudders looked good and the gelcoat layed down well for being thixotropic.

I have the fiberglass race rudders on my Hobie 18 and they came black so I figured why not re-gel with black. I picked up some neutral gelcoat and to that quart, I added a 1oz jar of black pigment. They mixed so easily, that I mixed it by hand, first by stirring, then by shaking. To this mix I added the standard recommended amount of wax which is 1 oz per quart.

One batch covered one side of the rudder with about 20 mils thick of gel, overkill, but I am trying to hide some deep gouges and what not. There was a bit of overspray. I think I will try to mix about 10 oz next time and shoot both rudders at once next time. After the spray up, the rudders were left to cure under a halogen lamp in the garage as it was night time, and the weather is getting cool. I noticed an odd effect of the waxed gelcoat, after it had cured, the surface turned light grey, It was the wax coming up the the surface.

I’m going to try to wipe it with something to see if I can get rid of it before I start to sand.

Pictures coming soon.

Righting pole designs

Posted in Boat Mods on October 25, 2006 by chrischow

I have decided to build a type of pole which fits into the dagger board trunk. The design starts with a cheap wooden boat oar. I think this is similar to the SoloRight designs by Gary Lastname? I have old read about the design.

A few things to do to the oar.

  • Lengthen the paddle, it’s not long enough for a single handed, no wind, righting
  • Fatten up the paddle end so that it fits better in the trunk
  • Put a flange on the paddle for a positive stop on the hull
  • Fiberglass the whole thing for a stiff part.

Spraying Gelcoat

Posted in Boat Mods on October 25, 2006 by chrischow

Setup your work bench with all the essential tools and cleaners for a well planned batch of experimental spray jobs. Here’s a few things I have learned in the process of making a batches of gelcoat sprays.
Step one, get some gelcoat…

evercoat gelcoat gelkote
This is un-waxed gelcoat. Using this un-waxed gelcoat on the outside of a part will expose the “wet” getcoat to air, which inhibits cure. This leaves a sticky layer on the outside. Why the hell is there a feature like this? Well if you wanted to laminate or add another coat of gel/resin on top this gelcoat, you will get excellent adhesion without any sanding. This gelcoat is designed to be sprayed onto a fiberglass mold and then sandwich layered with fiberglass and resin. Or it can be sprayed in multi coat stages on a part.

On the last layer you have a few choices. You can spray your gel, then spray an air barrier of PVA wax or Pledge(seems to work). Or you can mix into your final gelcoat batch and styrene soluble wax. Polygard has something called WAX-SOL. Sometimes its called sanding aid. Polygard also sells gelcoat with wax already in the mix. Some companies call waxed gelcoat and resin Finish Coat, and un-waxed, Laminating resin.

On coloring gelcoat. There’s white, neutral, and clear and sometimes y I mean black. Black is pretty much neutral with black pigment which is what I picked up at TA Mahoney

Thinning Gelcoat:

You need to thin out the gelcoat if you want to use a siphon or gravity feed spray gun. Not too sure about pressure pot type of guns, and “cup guns” with rather large nozzles designed for spraying gelcoat need not to be thinned. Thinning agents range from Acetone, Styrene and MEK. Evercoat recommends 5% maximum addition of Acetone. Most other gelcoat brands dictate the same maximum percentage, however they recommend Styrene. This was interesting, however, not knowing, I was to follow the label. But the problem with Acetone, is that, like using wooden stir sticks, it effects the cure rate of the resin by “killing” some of the MEKP. It can make the gel very very slow to cure or even, not cure. I found this to be true as a batch I mixed with a high level of Acetone, about the max of 5%, had a lot of extra tackiness on the outer layer even with a barrier coat of wax. MEK is slow to evaporate, so its prone to cause porosity on the part.

Styrene is what gives these resins that nasty smell, as it is what is in resin and gelcoat already. So it makes sense to use this to thin gelcoat. Haven’t tried this, but the next batch is going to have some.

Get a sprayer…

Cheap HF spray gun

This sprayer is from the good ol’ Harbor Freight. 11.99 yikes its cheap. Yea, it doesn’t spray with a damn. Im thinking about modifying the tip by drilling it out to about 2.5mm or 3/32″. The stock nozzle is 1.5mm. I think it can be enlarged as as half the diameter of the needle valve which controls the flow. I might loose some control with the enlarged nozzle. But since the gelcoat flow rate is so low as it is not a real issue if it works. I think I will try a few sizes in between stock to 3mm as to find an optimum. Most places with recommend a nozzle size no smaller than 2.0mm and I have read of 3.5 mm.

Other tips and tricks include using as much fan spray as possible which keeps the spray concentrated. Spray from 8-12 inches. And spray a coat of thickness from 15-20 mils. MEK is a good gun cleaner. Acetone is good too. Perhaps better. You can spray batch after batch with acetone flushings in between. Back flush a gun by adding acetone to the cup and holding a rag to the tip and triggering the gun.

Setups I have tried so far:

Acetone thinned 1% on the HF gravity feeder stock tip size
Acetone thinned 10% on the HF gravity feeder stock tip size
Acetone thinned 10% on the HF “touch up” siphon stock tip size

So far, no luck, all the batches so far shot too weak and thin. It took a long time to achieve a good thickness which lead to much orange peel and rough ness on the part. Im definitely going to drill out the tip of the gravity feed gun…

Check out:

more to come…

Cargo Trampoline

Posted in Boat Mods on October 19, 2006 by chrischow

Adding Cargo Trampoline to the Hobie is going to require a little research on what works and what doesn’t. My priorities for this mod is…

  1. The least amount of irreversible changes to the boat, ie no huge holes drilled everywhere.
  2. Doesn’t load the hulls or the beams in any way that can damage the boat structurally
  3. Not in the way of the jib sheet or other parts of the original setup
  4. Strong enough to hold a cooler with ice and beer, and camping gear, a few gallons of drinking water.
  5. With a load, the cargo tramp should not drag in the water
  6. Low windage, think capsized and blowing away.

Heres some links I found while looking for pictures of other peoples’ rigs.……

I was most impressed with a man I meet at Dunedin who had a sweet setup on his Prindle 18. Here are some pictures of this rig.

Prindle 19 trampimg_2922.JPG

Im going to need a gallery to link to soon, hows that flicker thing?