17' Titan aluminum, twin Tohatsu's or Yamaha single jet?

Ardent · 16 May 2015, 16:43

I'm a hunting outfitter on the north coast British Columbia on the Alaska border. Just purchased a 17' Titan Aluminum hull with Wing tubes, it's going to be used for running clients two hours along the coast into the hunting / fishing area, and then getting up the rivers hence the jets.

Engines I'm looking at are,

-Twin Tohatsu 35/50hp jets, two of these are the same weight as the one Yamaha, and I like the redundancy. Could also lift one off and put it on a light / cheap aluminum hull for getting way up into the rivers.

-Single Yamaha 65/90 jet or 80/115 jet, and likely a 9.9 kicker for fishing and backup.

Both the twin Tohatsu's and the Yamaha are the same price as my cousin runs a marine shop that deals in Tohatsu, he also can set up the twins so no concerns on getting them to work. What would you guys suggest? Quiet is nice and the Yamaha would be better there, just how much better is the question.

And hello all, good to be here!

prairie tuber · 16 May 2015, 20:43

Wow, that looks like a great up in the making for the purpose. If you go with the bigger single engine, you will probably get a higher top speed and better fuel economy than the twin. You could still have a small auxillary outboard to limp to shore if the main engine goes.

I guess a lot depends on what sort of communication and support your have available to you from where your base lis located. Would you have radio communication throughout the distance to the outpost, and would someone at the base location be able to respond quickly with another boat to give assistance if needed?

If that were the case, I'd lean toward the bigger maine outboard with a small auxillary for limping back to a shoreline.

Ardent · 16 May 2015, 21:35

Either way I'd feel comfortable, just with one 35 jet instead of a 9.9 the trip back would be much more pleasant. We're truly remote, but with sat phones things are easier now if something goes wrong. This said the cost of calling help is extreme. I actually would likely enjoy driving the Yamaha more and they're supposed to be silly reliable, but the twin Tohatsus would be more versatile, especially with the option of running one as a single on a lighter boat. Decisions decisions.

jyasaki · 18 May 2015, 18:31

Looks very similar to my boat, a 17.5" Polaris aluminum RIB. I'm running a single F115; Occasionally wish I had a bit more power when I need to carry a bunch of divers and gear.

Assuming you're using this thing for charter hunting trips, I'd opt for the redundancy of twins, but more in the 60-75hp range, if you can. Twin 75's would give you about hte same real world output as a single 120 or so (ignoring the inefficiencies of the jet), and give you something more than walking speed should one fail.

If it's just recreational boat, a single would be fine, moreso with the addition of a kicker.

jky

Ardent · 21 May 2015, 04:54

Exactly, running hunters and gear in, and meat and all out. Good info and I appreciate that, nice to hear from someone with a close setup. What does your Polaris manage for fuel burn, and speed at WOT if you don't mind me asking with the 115?

prairie tuber · 21 May 2015, 06:47

Quote:

Originally Posted by Ardent

Either way I'd feel comfortable, just with one 35 jet instead of a 9.9 the trip back would be much more pleasant. We're truly remote, but with sat phones things are easier now if something goes wrong. This said the cost of calling help is extreme. I actually would likely enjoy driving the Yamaha more and they're supposed to be silly reliable, but the twin Tohatsus would be more versatile, especially with the option of running one as a single on a lighter boat. Decisions decisions.

Makes total sense. I once had an older outboard pack it in on me while moose hunting in Manitoba during a mini snowstorm. Our camp was on the other side of the lake 3 miles away, and this was another 30 miles from the landing dock. Staying up all night keeping a fire going loses it's charm in a hurry.

Good advice from John that if using twins, go with something more powerful than 35s - especially with jets. Climbing rapids requires a lot of power.

jyasaki · 21 May 2015, 17:57

Quote:

Originally Posted by Ardent

Exactly, running hunters and gear in, and meat and all out. Good info and I appreciate that, nice to hear from someone with a close setup. What does your Polaris manage for fuel burn, and speed at WOT if you don't mind me asking with the 115?

Average about 4mpg; steps up on plane at about 17mph, cruises nicely anywhere from about 22 to 33 or so, WOT solo yields around 40mph. My boat is too beamy to be fast. I asked for it to be built to max trailerable width to get deck space for dive gear (and divers.)

jky

BRUTUS · 21 May 2015, 19:24

Dear Ardent,

First off, congratulations. Really solid looking vessel.

At the risk of offending our Euro brethren, whom by the way manufacturer truly nice stuff, I have to say that I have never seen better built RHIBs than what you Cunucks have to offer.

That boat there, paired with Californian MilSpec tubes, is awesome.

As my neighbor jyasaki points out, topside it’s similar in design to some of the RHIBs Guy builds; which by the way, from the information he has sent me and personal experience I’ve had up in BC, I would rank his RHIBs above American military boats like Willard, et. al.

I’m curious, does your RHIB have high-density polyethylene skid plates in lieu of a keel (like the picture I’ve attached)? Fits your purpose, I would say.

As to your questions, I would opt for a single Large outboard diesel such as the new military oriented Mercury’s (OptiMax Diesel – Reporting for Duty! | Mercury Racing).
For the application you describe, torque is more relevant than Hp and the diesel’s have that in spades. In terms of redundancy, given your remoteness, I would also append a small Japanese 2 stroke diesel outboard with zero electronics, they still manufacture them and you can purchase them, but obviously you won’t find them in North American dealers. If you operate in the winter, you can use JP8 which has fuel additives against gelling, mold and most importantly you can stash barrels of the stuff well in advance as it lasts much longer than anything out there.

By all means, post a URL of your operations, who does not want to hunt Northern BC!?

BRUTUS

Ardent · 23 April 2016, 18:07

At the risk of disappointing the forum a very different boat was built in the end.

The Titan, while exceptional, I backed out of after two inflatables were eaten by bears whilst beached in the territory.

Instead I built an ultralight welded aluminum 16' boat on a Riverhawk ProV16. I did proceed with the twin Tohatsu jets, and glad I didn't put them on the Titan as it would have been grossly underpowered.

The guide boat as it sits with the twin 50/35 jets makes 33mph at WOT with 60 gallons fuel and two people on board, not terribly inspiring performance but functional.

I've shifted from plans of trying to do everything with one boat to having one much more dedicated shallow water guide boat, and a 40' diesel as a supply boat and floating camp. I may invest in a Hewes offshore or the like (likely a Kingfisher being Canadian) down the road to move faster.

Thanks Brutus, my site is www.wildcoastoutfitters.ca

While not an RHIB, the tiny twins may prove academically interesting here,

Ardent · 23 April 2016, 18:12

jyasaki · 24 April 2016, 03:46

Looks nice. Glad you got things sorted out.

jky

headdamage · 01 June 2016, 22:47

The new boat looks like it might have been made by Silver Streak. Bears and their habit of messing with things does concern me here on Great Slave Lake. If I had the money I would likely go with an all aluminium self bailing design of some sort.

Ardent · 01 June 2016, 23:59

Maple Marine in Langley BC assembled it, hull was welded in Oregon (River Hawk). It's proving an excellent little work boat, after I came to terms with moderate (less than a couple hundred hp) jets just not providing impressive top speeds.

I think once I get the engine height and trim tweaked, they're running too low and too much positive trim, it should do 35mph or better. Slow in the quick boat world but functional, I cruise it as 27 knots and what makes me think the speed hangup is the jets is no matter what's in it, it always goes within a knot or two of that. One person, 90% throttle 27 knots, four guys, a grizzly bear skin, four jerry cans, day packs, anchor & chain, and it does 25kts at the same throttle. Likely just a certain point where the velocity of the water you're pushing won't push it faster, and I don't want to play with impellers and all. The holeshot knocks you off your feet, then it just stops accelerating.

Lots of info but ten years from now somebody may google "twin tiny jets" and this may be useful to them, I can't tell you how many forum golden oldies have been useful to me!

Ardent · 02 June 2016, 00:13

Here's a pic of her earning money. The video's got a few segments of running the rivers and fjords.

http://youtu.be/HEcKzBFpN_s

Ardent · 06 June 2016, 17:15

headdamage · 06 June 2016, 17:19

That boat would be perfect up here in Yellowknife

Ardent · 07 June 2016, 13:40

Does pretty well here too, been out on Great Slave and man, that's an inland ocean. Haven't been back since the bridge was put in (we used to live in High Level / Vegas North), was still the ferry last time.

I'm going to have to try it on props, it should be scary fast set up that way.