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PostPosted: Thu Feb 26, 2015 12:06 pm 
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Like many of you, I would like to have a small 4-stroke outboard on my TI for an extra mechanism of propulsion and for safety in times of steering loss.

There are many great ideas on the forum about mounting gas motors. My question is...

What is the best way to utilize the rod holder mounts at the stern without compromising storage and without drilling holes in the hull?

Are the PVC mounts that many of you created standing up to long-term use? Is there any damage to the rod holders by going this route?

Thank you for any help/suggestions you can provide!


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PostPosted: Thu Feb 26, 2015 5:37 pm 
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Location: Sarasota,Key West FL
unagimon:
It all really depends on if you want something practical (simple design, under $15) or if you want to go all out with something really nice looking and fancy. Me I'm just a practical guy and just do what it takes to accomplish what I need, usually just in my garage with simple tools (basically all I have is an electric drill and hack saw) (It helps that I'm an engineer and understand all that force stuff, plus I spent 30+ yrs as a master tool maker).

Here is a pic of my first PVC motor mount I made in april 2010 for my first TI (it's still perfectly functional and hanging on my garage wall:
Image

That mount has been on 3 TI's and has 4 yrs and way over 10,000 mile on it, I have never gone out on my TI without a motor. When I converted over to twin engines last year I replaced it with a new mount made using the same construction, but with a motor mount on each side (they take about 2-3 hrs to make).

Here is a pic of the twin motor mount
Image

Keep in mind though that the rod holder pockets themselves are not very strong ( they are un-supported down below) so they are only position holders for the PVC, all the rotational torque from the motor thrust is taken up by the small piece of spectra string tied to the motor shaft and anchored to the padeyes near the back of the boat (look at the grey string in this pic)
Image

The spectra is zero stretch 700 lb test line (same as Hobie rudder cable), the string you see in the last pic is the original string (five years old) and still going strong, the stuff lasts forever.....

Hope this helps
Bob


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PostPosted: Fri Feb 27, 2015 7:02 am 
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Location: Colorado
Quote:
all the rotational torque from the motor thrust is taken up by the small piece of spectra string tied to the motor shaft and anchored to the padeyes near the back of the boat (look at the grey string in this pic)


aha... that makes a lot more sense now and should be robust.. The plastic in the kayak seems to be very strong but I couldnt understand before how the rod holders handled the torque.. That extra line looks like a very simple way to add a lot of strenght.

You can see some very simple electric motor mounts that look like they work very nice but consider that a 30 pound thrust electric motor uses about 25 amps at full power which is on the order of 300 watts. Its not apples to apples (and I dont know how to exactly compare) but 2.5 hp is on the order of 1860 watts. This is a factor of over 6 times as much power as the 30 pound thrust electric trolling motor so things need to be a little more robust.


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PostPosted: Fri Feb 27, 2015 8:47 am 
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Location: Sarasota,Key West FL
walt:
Yes the rotational force is huge (both on electric and gas motors), with the force applied 15 inches below the fulcrum point (the prop turning), its similar to a lever, where you can lift your car easily with a brick and an 10 ft 2x4, you have two choices either over-design the mount itself so it can withstand the 1500 lbs of rotational force on the fulcrum point (option 1), or spread the load over a larger area (like the guy wires on a bridge) (option 2). With the mount being made from simple PVC tubing (about $3 dollars worth of tubing and fittings ), and the rod holders being totally unsupported inside the hull, option 1 is out of the question.
Of course I could have designed around option #1 but it would have taken a lot longer than 2 hrs to make, and more than the $10-15 bucks I spent.

Keep in mind this was just something I threw together in a couple hours. When we bought our first TI in April 2010 (on a thursday afternoon), my wife and I went straight from the dealer and launched at City Island (in Sarasota) at around 4:00pm. We were having a blast and took the boat outside of big pass and went into the gulf (about a mile offshore), at around sunset every day around here the wind totally dies and goes still. The tide was going out and the current coming out of big pass was running about 5-6 mph (big pass is about a mile wide, and all the water filling the intercoastal for 15 miles to the north, and 15 miles to the south must flow mostly thru that pass (I would assume a gazzilian gallons (lol))....who knew....
Both my wife and I pedaled our little hearts out for about 2.5 hrs trying to get back in thru the pass. we were totally exhausted (and very frightened by the experience). She suggested I buy a motor just in case something like this ever happened to us again (free ticket to buy a motor from wife......). I ordered the motor that night, made the motor mount on Friday evening with stuff I already had laying around the garage (exact same motor mount in the pics above), and picked up the motor Saturday morning. We went out again Saturday and had a blast (with the motor on the boat as a safety backup, that motor was a 20 lb Island hopper gas outboard (I'll never buy another one of those....POS)).
We love our TI and are out pretty much every single weekend on it, our average trips are between 15 and 60 miles every weekend all year round.
We have never taken out TI out without a safety backup motor mounted on the boat since then (and probably never will).
I never put another moments thought in to the motor mount, whenever we buy a new TI (we are on our 3rd now), I just transferred the motor mount and the motor, along with all the extra sails (jib and spinnaker, bow sprit, etc) and all the extras that I made during the first few months we had the boat to each new boat without thinking much about anything (we just use the stuff). When I added the second motor last spring (I have no idea why, really for no reason) I made a new motor mount that holds two engines instead of one using the same exact simple design. I could care less what anyone else does (or thinks about us), this works for us, and that's all I care about. I was asked to share some of my junk by some of the forum regulars back in 2011, so I did.
Moral of the story, if you want to get a motor, take your wife offshore (works every time).
Bob


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PostPosted: Fri Feb 27, 2015 9:26 am 
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Hello Bob

Thank you for sharing your experiences and insights. I like the simplicity and utility of your design.

I am sailing mostly off the southeastern coast of Grenada, West Indies. We have consistent trade winds from the east at 15-25 mph (offshore wind from most of my vantage points on the leeward side of the island). There is also a current that pulls south which is typically around 2-3 mph. A gas motor will give me much better offshore capability and confidence making it back to the beach with a catch of tuna and mahi! Best, Brian

This forum is a tremendous resource, but I am finding information about motor mounts scattered all over the place. A bit difficult to navigate.


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PostPosted: Fri Feb 27, 2015 9:26 am 
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Location: Colorado
My application.. I have been sailing an AI for a bunch of years and never really needed the outboard (pedals and sails work fine) but.. I think the motor will open up some possibilities with the TI.

I posted this on a different forum but am really thinking about the TI as a great way to expore the San Juan Islands (Washington State).

https://maps.google.com/maps?q=san+juan ... d&t=h&z=11

You can see that within a 10 mile range from Friday Harbor, you can get a huge range of places to explore. I found I could comfortably do 6 knots still using almost no gas (remember we are talking about really tiny gas outboards here) and in 1.5 hours of motorig (3 hours round trip), we could zip over to some spot, sail and pedal for a bunch of hours to explore the area, then zip back.

And.. I will save an enourmous amount of gas by not hauling the sailboat up there with a V8 truck.. I think I maybe would go through a gallon of gas or two in a week. That outboard is only about 30 pounds so also easy to remove each night.


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PostPosted: Fri Feb 27, 2015 2:24 pm 
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Location: Sarasota,Key West FL
walt:
That pretty much follows our line of thinking, one thing we discovered is that the Florida Keys and the Florida intercoastal system is huge, and available launch sites are far and few between. We use our TI as our family boat, and mostly use it to go out snorkeling and scuba diving (our favorite pastime), or just meeting our powerboat friends and hang out at local restaurants/bars and sand bars for the day. We also discovered pretty quickly that pretty much anyplace right near shore and most of the public areas are just barren sand for miles around (no fun for snorkeling and spear fishing)). As former powerboaters we can no longer afford to keep and maintain powerboats, where you can easily burn up $300 bucks in fuel over a weekend. Dry boat storage in Sarasota is around $400 a month any place you go, and as everyone knows a nice 21ft-25ft Sea Ray will set you back $60-$80k (pretty much the minimum size boat we could use in these waters). We ended up selling our powerboat and use the TI for pretty much everything we previously used our powerboat for. Basically we use the motors and extra rigging to get us where we want to go in a decent time, then kayak and sail around at the destination for the day (usually sans the motors and fancy sails, just tilt the motors up and keep the big sails furled up).
One thing we do often is meet up with our powerboating friends at different beaches or sand bars and spend the day, like off of Egmont Key. Typically when we go out in the summer the typical winds are 3-6 mph pretty most all the time. We could of course launch at our regular launch and make our way up to Egmont key (about 20 miles), if sailing and pedaling a stock TI in those conditions we average around 3mph ( a 6-7 hr sail to get there) then another 6-7 hrs to get back (man vs sea). Or we can do the trip in about 90 minutes with our boat rigged the way it is currently, using about a dollars worth of fuel for the day. ( I prefer the latter), BTW we are not hard core sailers (man vs sea and all that stuff), and probably will never be (that's probably obvious, our boat is our utilitarian SUV). We just like to spend time out on the water and want to have fun, thats it....different strokes for different folks


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PostPosted: Mon Mar 20, 2017 3:47 pm 
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fusioneng,

I'm interested in your motor mount design. Do you mind posting some details as to the construction and materials used?

Thanks!
David


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PostPosted: Wed Apr 12, 2017 4:20 am 
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Hi Fusioneng,

I'm about to buy some materials to build a mount. Could you tell me how wide yours is?


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PostPosted: Sun Apr 23, 2017 9:59 am 
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I'm not interested in a motor mount but do want a tower to get main sheet lines above rear passengers head and get reels further from the waterline. Do all of these pvc style mounts start with pvc just bigger than the hobie rod holders heated and forced into rod holders to fit? Is there anything that fits just right (back to spreading force over a larger area).

Thanks

--dimes


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PostPosted: Sun Apr 23, 2017 3:20 pm 
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Location: Houston, TX
Most just use 1.25 inch PVC.

_________________
Greg

2016 AI - Spinn & Jib
2012 AI - Spinn & Jib

“Out of sight of land the sailor feels safe. It is the beach that worries him.”
– Charles G. Davis

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PostPosted: Sun Apr 23, 2017 3:59 pm 
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Location: Sarasota,Key West FL
I unfortunately didn't measure anything at all when I made my motor mounts, I just sawed off some 1 1/4 or 1 1/2" PVC, (I don't recall which size I used, whichever one fits in the hole) that looked about right, then used that piece to make a duplicate and shoved them into the rod holder holes. The rod holder holes are angled back and outward at compound angles so there is no means to measure anything, just build as you go marking the lengths needed with a sharpie then saw off with a hack saw as needed. Once assembled, but not yet glued, I just eyeballed and drilled thru the 1/2" dia side holes on 2 1/2" centers. The height from the gunwale is the width of two fingers, (probably should have been 3 fingers). To drill the pressure treated 2x4 around 7-8" long, I just drilled a 1/2" dia oversized (next size bigger) hole about the width of my thumb from the edge of the hole on the bottom and about the same from one edge (front edge on one side, and rear edge on the other). I just eyeballed the squareness.

I then put the first 1/2" dia x 3ft aluminum rod (from Lowes, bought two of them, they must be 3ft long, thats what the label says anyway). I slid the aluminum into the holes on each 2x4. I then rotated the 2x4 so it looked straight up and down and held it there. I then shoved the drill into the second pre-drilled cross hole in the pvc, and started the second hole. Once the hole was started I pulled the 2x4 off, set it on the ground (hole pointing up) and drilled the remainder of the hole, as long as the drill bit using my body weight to make it easy to drill, using my feet to hold the board straight and keep it from spinning.
Before putting together the last time take a paper towel and jam it into the pvc a few inches below the bottom hole. If you were sloppy when drilling the cross holes (mine ended up oblong a bit) so I had to tape over the holes with masking tape on the outside of the pvc). I went to walmart and bought a quart of polyester resin, and a tube of that white locktite marine epoxy.
I filed a few notches into the end of the aluminum rods to help the epoxy grip better. I then mixed up the white marine epoxy and lathered it over the ends of the rods and jammed some in the holes in the ends of the 2x4's. I then jammed the 2x4's onto the pre-assembled pvc with the rods sticking out.
Next I mixed up the polyester resin in a bucket and poured it into holes at the top of the pvc until the rods are covered about an inch or so. If you did a good job with the paper towels and the tape over the cross holes, the polyester won't run out the bottom, if it ran out the bottom, then you gotta go back to walmart and get more resin. When setting up the polyester resin gets hot, don't touch it. The polyester takes ten minutes to setup, and the marine epoxy take 24hrs.
Once the polyester cools down, you can get your pvc glue out and glue the rest of the pvc joints and elbows (final assembly). You now have yourself a nice motor mount that will last pretty much forever.
If you wanted to get fancy you could have vacuum bagged the wood before assembly with a mixture of 2/3 west systems epoxy and one third denatured alcohol. I'm a custom boat builder and always vacuum bag all wood (totally unneccessary), just force of habit on my part.
Don't forget the spectra string on the lower unit if your using a big powerful outboard. The rod holders themselves are not supported down below and can't take a lot of rotational force.
Took me a couple hours to make mine (not including the second trip to walmart to get more resin).
Hope this helps
FE


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PostPosted: Sun Apr 23, 2017 8:08 pm 
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Location: Austin Texas
If you Search for "roll bar" you will find what you are looking for.
Here's one :

https://www.hobie.com/forums/viewtopic. ... ar#p280809
Another one on You Tube :
https://www.youtube.com/watch?v=PbfLwt1BCPs&t=27s

Don't " heat and force " anything into those holes, they are not well supported inside for anything other than what a fishing pole would do to them.


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