Snake Shooter boat in Aluminum to big for my motor

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Joeyak49
Posts: 5
Joined: Mon Nov 23, 2015 12:15 pm
Location: Anchorage Ak

Snake Shooter boat in Aluminum to big for my motor

Postby Joeyak49 » Wed Nov 25, 2015 9:00 pm

Snake Shooter boat in Aluminum to big for my motor. My motor 2015 tohatsu 50 hp two stoke I want to be able to use the boat on the Kenai River or take it out on the inlet on nice days or take it to Whittier and do some shrimp I'm new to this so all the help I get will be appreciated

Kevin Morin
Posts: 672
Joined: Thu Jan 24, 2008 11:36 am
Location: Kenai, Alaska

Re: Snake Shooter boat in Aluminum to big for my motor

Postby Kevin Morin » Thu Nov 26, 2015 1:02 pm

Joeyak49,
When we talk about matching an engine to a boat design- I think there are some things to get set; before you make decisions. For example the 50hp engine on the 20' boat, completely empty, low fuel, no one but you driving, and stripped to the hull- will plane the hull with the right prop.

But the same boat, with full fuel, groceries, gear and a couple fishing buddies of the family- which will move the displacement from a bare boat 800-1,200lb? up to closer to 2,500 lb. (or more) the 50 will struggle to get moving.

NOW... what if you said all you wanted was to go 10-12 mph fully loaded? (bringing up my original 'givens in the design' idea, above) Then the 50 will move the Snake Shooter hull at slow speeds, but the bow wave will be horrendous, given her river runner design heritage and bow shape! The purpose of this type hull design is run fast in 'skinny water' - very shoal draft, skipping along the surface.

Use of the boat- the Snake Shooter in the lower Kenai- below the W.Ames Bridge, where you're confined due to the 50hp instead of the 35 hp allowed upriver, will be fine since you're confined to no-wake speeds primarily and will only be dipping at very slow trolling speeds.

The Cook Inlet trips are somewhat questionable for safety as the very slow speeds possible with the fully laden 20' boat going that slow means that steerage in a swell is not too good. So, I can see a typical scenario where you might leave the Kenai River, go out to fish on the ebb without a breeze in sight, and if the flood tide comes up in the pm? you may find yourself in a following sea trying to get back to Kenai and your steerage in this boat at displacement speeds in a 3-4' following sea might not be safe- the hull is subject to broaching in a following sea in displacement mode. So for that use I can't agree this hull with that low power would be a good choice.

However, this hull with a 70 or a 90hp would be fine in the Cook Inlet, but I'd want to explore the design for the underwater appendages in the after 1/2 the hull. Longitudinal extrusions on the bottom of this type of hull will help keep the steerage safe in a following sea, so will higher speed or more power where you can ride the throttle and stay on the wave backs. So... my opinion of the hull (for this use) is; with more power and external rails she's fine in a following sea but not without both considerations.

Whittier is very sheltered, but even then when a wind comes up the fjord things can get lumpy! My opinion of using an open 20 in this area are similar to the use in Cook Inlet, I'd want to see more power (available) and to understand the "longitudinal resistance" or 'keel area' provided in the aft one half of the underbody before agreeing this boat would be useful in the salt water?

Often a river sled jet boat type hull has all the structural framing inside to keep the boat's bottom 'clean' for sliding jet steering. This is OK with enough power for river use. But that same hull in salt water could get into a course (down wind and wave) that presents the stern to the weather (wind and waves) and the speed is not being used (if there are waves and you go too fast you jump!) so... the ability of the hull to "track" becomes a balance between the waves lifting the stern and the bow being pushed down into a wave (back). Sometimes this condition ends up turning the boat side ways (broach or on 'beams' end) so the waves come at the boat from the side- not the bow or stern.

I don't know the hull's design details, but I'm sure you can explore her study plans and learn what the design calls for for power and then learn what her hull longs offer in the way of a keel area to resist slewing sideways in a following sea? There are definitely boats of this general class and approximate shape in these waters, but not many use a 50hp for the reasons I've mentioned.

Hope this helps your planning process? I've lived in Kenai since Statehood, so I've had some experience in the waters you're describing.

Cheers,
Kevin Morin
Kenai, AK
Kevin Morin

Joeyak49
Posts: 5
Joined: Mon Nov 23, 2015 12:15 pm
Location: Anchorage Ak

Re: Snake Shooter boat in Aluminum to big for my motor

Postby Joeyak49 » Thu Nov 26, 2015 1:31 pm

Kevin thank you for all your help boat plans would you recommend be build for what I want to do and if I added two 50 hp
Would that enough power.

Kevin Morin
Posts: 672
Joined: Thu Jan 24, 2008 11:36 am
Location: Kenai, Alaska

Re: Snake Shooter boat in Aluminum to big for my motor

Postby Kevin Morin » Thu Nov 26, 2015 1:52 pm

Joeyak49,
the Snake Shooter with 2 50's will do just fine, I'd still want to look at the rails or 'short keels' to see what they are called for in design. But the twin skegs of two outboards would give lots of 'keel area' to keep from broaching if you were moving slowly in a following sea.

The Chinook design has been built in this area twice that I personally know about, that bottom's design is a little more V'd than the river jet Snake Shooter, and that is no problem in the lower Kenai, obviously. As to the saltwater use the Chinook has a more traditional V bow (not as much rise to the chines as a river jet boat type hull) and has performed well in both the Inlet and in Kachemak Bay. Snake Shooter would pound a bit more than a Chinook in waves of any size.

Also, depending on your layout, cutting and fitting skills; the new S. Pollard pre-cut metal packages has a boat in this class the Orca 20, that would likely have more V and be more suited to saltwater, like the Chinook is, compared to the Snake Shooter being designed more for fresh (shallow) water.

Both the Chinook and the Orca 20' seem to favor the 100hp range engine size- compared to 50hp range engine- but I'm not sure if they're designed with twins in mind? That is not a huge change in the build of a metal boat, going from one engine to two, but it should be noted that if the original designs don't take that into account, you'll need to plan for the other engine on the mounts.

Either of the Chinook or Orca could be configured open boat and console, small cabin or weather helm and if some design work was added (?) they could be stretched a bit and larger cabins added as well. So, while not the same boats, they're in a size class and hull type for the area and waters you're discussing.

Hope this helps? & Happy Thanksgiving.

Cheers,
Kevin Morin
Kenai, AK
Kevin Morin


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