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 Post subject: Re: TI outboard mount
PostPosted: Thu Dec 28, 2017 5:03 pm 
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Joined: Thu Aug 16, 2007 2:25 pm
Posts: 2771
Location: Central Coast NSW Australia
Just to clarify, when I said ‘bare minimum depth’ I meant the minimum depth needed to ensure the pump never sucks air or runs dry. That is the most crucial measurement. Being able to operate in shallow water has proved a benefit many times and adds to the TI’s versatility. Just yesterday I was trying to launch solo in water too shallow for the rudder, into a 20 knot headwind. I couldn’t keep the TI straight with just the paddle. Ended up reversing out with the OB swivelled 180.
Here’s how my OB sits in the water when the kayak is unloaded. This position has worked well the last year or so.
Image



BTW Walt, just before Christmas the Tacho arrived. It was an easy fit and it works well. I mounted it with industrial Velcro for now, so I could experiment with the best position.
At about 4500 rpm = 5-6 knots, 2700 rpm = 4 knots depending on water conditions.
It’s worth it just for the hour meter, so thanks for the heads up!
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 Post subject: Re: TI outboard mount
PostPosted: Fri Dec 29, 2017 4:40 am 
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Joined: Sat Nov 05, 2011 1:58 am
Posts: 2818
Location: Forster, NSW, Australia
Thanks for the info Stringy! In line with my policy to "Make China Great Again" :lol: I have ordered a similar item for AUS$8.69 plus AUS$0.20 postage (obviously a very slow boat from China), to measure the rpm of my Hangkai cheapie "3.5hp" two-stroke.

It only increases revs halfway through the throttle movement, just increasing smoke but not revs. Time to see about tuning!, but first see what revs it is pulling.

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2012 Tandem Island "SIC EM" with Hobie spinnaker and Hangkai outboard
only cool people follow the (non-magnetic) titanium weight-loss program! lol.)


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 Post subject: Re: TI outboard mount
PostPosted: Fri Dec 29, 2017 10:28 am 
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Joined: Thu Jun 01, 2006 1:16 pm
Posts: 566
Location: Colorado
Quote:
At about 4500 rpm = 5-6 knots, 2700 rpm = 4 knots depending on water conditions.


Great info! That tach probably has multiple settings for the number or sparks per rev. Do you remember the setting you used as the RPM numbers you posted sound correct? I think you picked the one that has the two wire (signal plus ground) pickup...

Also, have you measured the RPM at wide open throttle?

I really do not power sail in winds over where my peak speed would be about 9 mph or about 7.8 knots (dangerous to have some sort of capsize with the props grinding away) but what about peak RPM with any wind and pedal assist - since that gets discussed a lot?

FYI, I think that data says the prop on the Suzuki 2.5 is close to ideal for the TI but if the goal was to go faster and you only achieved a peak RPM of 4500, you would need to re-pitch the prop to get to higher RPM. This would require a LOWER pitch prop. I think one poster went to a higher pitch prop (wrong way) with this outboard and likely ended up with even lower RPM that 4500. This would have reduced the available HP and possibly bogged the engine with higher torque than the manufacture intended.


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 Post subject: Re: TI outboard mount
PostPosted: Fri Dec 29, 2017 1:44 pm 
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Joined: Thu Aug 16, 2007 2:25 pm
Posts: 2771
Location: Central Coast NSW Australia
Tony,
:lol: Yeah, I’ve been making China great for years as well! My Tacho was the two wire version AUD $18.99. Only took 2 weeks to arrive despite Christmas. I hope you are back on the water soon.


Walt,
I’ve only had it out once with the Tacho and conditions weren’t ideal with 20 knot gusts. It was great sailing though!
The default Tacho setting is 1P1r=1spark per revolution and first start after fitting displayed 2040 rpm at idle in neutral.
This was close to the Suzuki idle spec of 1800-2000rpm so it looks like the Suzuki does fire 1spark/rev.
According to the Suzuki manual max revs = 5250-5750rpm. I didn’t check WOT this time but will do more tests when conditions are better for motoring.
I’ve always agreed with you that the Suzuki 2.5 is fine as is but it will be interesting to have that backed up with figures.
More to come ....


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 Post subject: Re: TI outboard mount
PostPosted: Mon Jan 22, 2018 8:42 pm 
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Joined: Mon Nov 10, 2014 7:10 pm
Posts: 39
Am beginning the steps to add a motor to our (new-to-us) 2017 TI for our annual winter fishing trip to the gulf next month. We are used to fishing out of our Pro Anglers, which have most fishing needs built in or easy to add. I am initially looking to add some rod holders. Putting the motor mount and rod holder into one unit pushed me toward using PVC rather than aluminum.

I used some of our 20 below zero weather to read the very helpful posts and begin assembling a motor mount/rod holder. This first try is a close copy of BobAgain’s PVC motor mount. I also looked closely at fusioneng’s mount/numerous posts. I relied on Stringy’s advice for motor placement: just in front of rear hatch, about 8.75 inches above the gunnel and as close to the hull as the prop allows. I could not decide on port (stringy) or starboard (BobAgain), so I punted and used a 3 ft section of double-sided composite decking for affixing the motor—which allows me to place the motor on either side.

With no on-the-water testing (our favorite Lake Superior launch sites have 12 inches of ice at the moment), first impressions are all I can offer.

The mount is held in place with 4 bungees: 2 each from front/rear eye-bolts to existing bungee hooks. The bungee provide a solid mount, but I have misgivings about the strength/fatigue of the existing TI mounted bungee clips.

The eye-bolts go through the mounting board and hold the 2 forward and 2 rearward vertical pipes together-adding stiffness. To add a bit more stiffness/strength, all the PVC pipe is stiffened by inserting a wood dowel siliconed inside (like fusioneng recommends for his PVC kayak racks). The resulting rigidity is great, but the added weight is noticeable. I added a short SS safety cable to the port (motor side) eyebolt which attaches to the motor's transom plate.

The upper half rod holders (4) are slotted to be rotatable (like MedicineMan’s post). I placed a Navisafe Navilight 360 white light on the top horizontal pipe to go with a red/green bow mounted one.

Am not sure how high to place the main sheet—it is now routed across the first cross pipe, 15 inches above the gunnel. The top pipe is 31 inches above the gunnel. So hoping somewhere between will work.

The mount is very easy to remove (unhook 4 bungees and lift out).

The mount’s rear-ward placement provides enough of the rear deck for my cooler/waterproof dog food container/emergency box will still fit.

Am a bit leary of PVC’s strength—esp when really cold; as I have broken enough of it over the years during our cold winters. It’s availability, low cost, ease of forming (and fitting into) rod holders, and esp other’s success with it got me to this point. I do see some very fancy aluminum rod holders/rocket launchers on larger Lake Superior fishing boats—so aluminum could be used in a lighter/cleaner design.

Thanks much to all those taking time to post the very useful tips. You really help us newcomers to the TI.

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Last edited by itiming on Wed Jan 24, 2018 10:39 am, edited 1 time in total.

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 Post subject: Re: TI outboard mount
PostPosted: Tue Jan 23, 2018 7:10 pm 
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Joined: Thu Aug 16, 2007 2:25 pm
Posts: 2771
Location: Central Coast NSW Australia
Nice work IT! 8)


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 Post subject: Re: TI outboard mount
PostPosted: Tue Jan 23, 2018 7:17 pm 
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Joined: Thu Aug 16, 2007 2:25 pm
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Location: Central Coast NSW Australia
I was recently able to get some accurate outboard info while motoring on a freshwater lake with no currents/wind and solo on an empty TI but with the mast fitted.
At WOT the tacho was reading 5380 rpm. Sitting in the back seat speed maxed out at 7.2 knots.
When I moved forward and sat in the front seat or out on the haka speed hit 7.7 knots.

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Cruising at around 4500rpm speed was 6.1 knots sitting in the rear seat and got up to 6.6 knots sitting in forward seat or haka.
Interestingly, speed didn’t change with the AMA slightly dragging when hiked out.


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 Post subject: Re: TI outboard mount
PostPosted: Wed Jan 24, 2018 6:34 am 
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Joined: Thu Jun 01, 2006 1:16 pm
Posts: 566
Location: Colorado
Another data point saying the stock prop on the Suzuki 2.5 is a good choice for the TI. Since the Honda does not have a rev limit, hopefully someone will do this same RPM vs speed test on the Honda.

FYI, I dont know about the speed puck set to capture peak speed but my Garmin will will have give an error in peak speed. Its a small error but at the the speeds we travel, it ends up being significant.

Example (this picture is hosted on fb so will go away but I will describe it). I was watching the GPS and my speed was bouncing around 7.9 to 8.1 mph (6.86 to 7 knots). But you can see in the picture that the instrument had recorded a peak speed of 8.8 mph (7.65 knots). Since I was watching the instrument, I know I never actually hit 8.8 even for an instant.

Your difference in speed between front and back seat is surprising.. I will have to try and duplicate that but wont be using a peak speed reading since I know at least on my Garmin the peak speed errors will be significant.
Image


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 Post subject: Re: TI outboard mount
PostPosted: Thu Jan 25, 2018 4:11 am 
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Joined: Mon Dec 29, 2008 2:35 pm
Posts: 59
Location: Niceville, Florida
Nice work Itiming! Love the rod holder placement. I’m not an engineer or an expert (whoppin 6 hours motoring experience) but my gut feeling is that you are in for more vibration than you are anticipating. Just an observation, not meant to criticize just pure speculation.

_________________
'09 Adventure Island (SOLD)
2017 Tandem Island


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 Post subject: Re: TI outboard mount
PostPosted: Thu Jan 25, 2018 6:29 am 
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Joined: Sun Apr 26, 2015 3:13 pm
Posts: 326
Please be aware the PVC was never designed for such use and stresses, and may crack unexpectedly. I know some people have successfully use PVC for motor mounts, but I personally would never chose this material for such use. Gasoline motors vibrate constantly in addition to the forces they apply for propulsion. PVC is vulnerable to stress cracking over time.

I chose aluminum for my motor mount. Metal is far more suited to the stresses a motor will place on a mount for long term use. Aluminum is corrosion resistant, lightweight, inexpensive, easily procured, easy to work with, and most of, all incredibly strong when the correct thickness is used.

I do use PVC for my trailer cradle and even there have experienced PVC failure due to stress cracking.

My opinion only, take it or leave it as you wish. This is not meant as criticism in any way, I'm just trying to offer a balanced view for others here who may be selecting a material and design for their motor mounts.


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 Post subject: Re: TI outboard mount
PostPosted: Thu Jan 25, 2018 9:59 am 
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Joined: Mon Nov 10, 2014 7:10 pm
Posts: 39
Thanks much for the replies and the experience behind them.

Yes, I concur with PVC structural limitations. I took an expedient route with the PVC, as it was an approach I could put together in time for our first on-water trip with the new motor. My hope is that reinforcing with the 1.25 in wooden poles slip-lined into the PVC will hold the forces, even if (when) a PVC fitting breaks. Am looking to get enough service out of this mount to trial the best motor, rod, mainsheet height/location. The PVC motor mount fusioneng posts about had a long service life, as I believe it was reinforced (with resin).

Hoping the info from this initial trial gains me enough experience to better evaluate/design/source a stronger/lighter motor mount/rod holder/mainsheet router/light bar/fuel storage, etc. Without commercial units to select from, a custom fabrication is needed. Yes, aluminum is a better long term material--but I don't know the best means/location for attachment to the hull and placement of the motor.

Posts show motors mounted from as far forward as to the rear AKA bar to as far back as the stern--some with multiple motors. Posts show motors mounted low to high up from the gunwale, and to either side of the kayak. Hoping to figure out the efficiency's of these approaches before embarking on the next level of time/expense.

I much appreciate all the experience shared in these posts.


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 Post subject: Re: TI outboard mount
PostPosted: Thu Jan 25, 2018 5:30 pm 
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Joined: Thu Aug 16, 2007 2:25 pm
Posts: 2771
Location: Central Coast NSW Australia
walt wrote:
FYI, I dont know about the speed puck set to capture peak speed but my Garmin will will have give an error in peak speed. Its a small error but at the the speeds we travel, it ends up being significant.

Example (this picture is hosted on fb so will go away but I will describe it). I was watching the GPS and my speed was bouncing around 7.9 to 8.1 mph (6.86 to 7 knots). But you can see in the picture that the instrument had recorded a peak speed of 8.8 mph (7.65 knots). Since I was watching the instrument, I know I never actually hit 8.8 even for an instant.


Yes Walt, I’m aware of the peak speed errors and agree with you. My Garmin eTrex30 registered 14.9km/h (8.04knots) max speed for the same trip. I know the Speedpuck never registered that speed so it could be more accurate. I was regularly, but briefly, seeing 7.7knots but when I tried to take a pic underway I could only get 7.6knots which was the most common speed displayed:
Image


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 Post subject: Re: TI outboard mount
PostPosted: Fri Jan 26, 2018 3:19 am 
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Joined: Sat Jun 06, 2015 4:30 am
Posts: 230
Location: Delnor Wiggins, Fl Peters Twp PA
itiming wrote:
Thanks much for the replies and the experience behind them.

Yes, I concur with PVC structural limitations. I took an expedient route with the PVC, as it was an approach I could put together in time for our first on-water trip with the new motor. My hope is that reinforcing with the 1.25 in wooden poles slip-lined into the PVC will hold the forces, even if (when) a PVC fitting breaks. Am looking to get enough service out of this mount to trial the best motor, rod, mainsheet height/location. The PVC motor mount fusioneng posts about had a long service life, as I believe it was reinforced (with resin).

Hoping the info from this initial trial gains me enough experience to better evaluate/design/source a stronger/lighter motor mount/rod holder/mainsheet router/light bar/fuel storage, etc. Without commercial units to select from, a custom fabrication is needed. Yes, aluminum is a better long term material--but I don't know the best means/location for attachment to the hull and placement of the motor.

Posts show motors mounted from as far forward as to the rear AKA bar to as far back as the stern--some with multiple motors. Posts show motors mounted low to high up from the gunwale, and to either side of the kayak. Hoping to figure out the efficiency's of these approaches before embarking on the next level of time/expense.

I much appreciate all the experience shared in these posts.


FWIW I'm on my third season with the PVC mount and no issues (yet). I do run my Honda 2.3 at low RPMs (just above idle gives a surprisingly helpful push) and generally avoid freezing temps while sailing...


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 Post subject: Re: TI outboard mount
PostPosted: Tue Jan 30, 2018 9:11 pm 
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Joined: Fri Feb 26, 2010 2:03 am
Posts: 218
Location: Bundaberg QLD, Australia
stringy wrote:

Image
.


Hi stringy, are those MSR type metal fuel bottles I see strapped to your mount? I’ve moved from Canberra when you only use electric motors to Bundaberg where I can finally give my Honda 2.3 some more use. I’m just looking at refueling options.


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 Post subject: Re: TI outboard mount
PostPosted: Wed Jan 31, 2018 1:53 am 
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Joined: Thu Aug 16, 2007 2:25 pm
Posts: 2771
Location: Central Coast NSW Australia
Hi John, those are Trangia 1L plastic fuel bottles, bungeed to the outboard bracket. I also carry 2x 1L cheap Chinese aluminium fuel bottles I got off eBay. I’ve had no problems with either but you need to be careful when screwing the top back on the Trangia’s to avoid cross threading, as it is a very fine thread.
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