Tunnel

[Yesyoucan4]

I am finishing my XF 20 and liking the whole tunnel design. My question is I have a 1965 Super Skeeter that is similar to a Ghenoe. I wonder is the tunnel on the XF20 is the standard size for most boats. I can make it any size as I have to cut the hull. Thinking about a 25 hp on a jack plate. Is it doable

[cape man]

The Super Skeeter is too narrow, and a tunnel will make it very unstable. The LM 18 was partially designed to allow a tunnel that the narrower FS 18 did not for that reason.

My $0.02.

[TomW1]

Jacques enlarged the LS18 by 10" widthwise in order to allow for the tunnel. This makes for a smaller tunnel than is on the XF20.
Jacques designed the tunnels for each of the boats that have one, do not try to use one of the tunnels from one of the designs on a different design. A wrong tunnel design can really upset the boats performance,

Tom

[timoub007]

I am not sure what the width of the bottom of your 1965 Skeeter is, and that will dictate some of the performance of adding a tunnel.

Look at my build thread from almost 20 years ago for reference. I put a tunnel in the bottom of my GF-16 against Jacques wishes. I knew what I wanted (like most of us that are going through the effort of building our own boats) and knew it would work because we use small tunnel hull aluminum boats for shallow marsh duck hunting and fishing locally. At first I used the design from the XF-20 but was not happy with that. For getting water to the motor and prop it does a great job, but it compromises too much overall performance of the boat, any boat. Much has been said about tunnel design and I will never argue with someone as knowledgeable as J was.

I took a chain saw to the bottom of my boat and put in a different tunnel design that was much more efficient overall.

I am not sure where all of the pictures of my build disappeared to. I think that I used to use photobucket or some other free hosting site that is long gone.

Regards,
Tim

[Dr Pete]

I’ve been fishing my XF20 for 3 years now. Power is a 2 stroke 90 hp Yami. 2 features of the boat are when at speed it slides and takes 3 football fields to turn. Secondly the tunnel looses prime and the engine cavitates on any turn. Jack plate all the way down. None of this has impaired fishing from the boat. That’s why these things are “features”. Haven’t heard these comments made about the hull.

[rick berrey]

Looking at the study plans the max hp should not be over 50 hp , don't know if higher hp and speed affects the tunnel or hull performance but I would think it would .

[Dr Pete]

Rick the bare bones of the xf20 may not even have a sole in it. It would be very light in that configuration. Finished out with sole, fore and aft decks, center console….the craft will very safely manage 115 hp and likely more. I just reviewed your comment regarding power. 25 hp would be a very poor performing boat. My XF with 90 hp tops out with a strong tailwind and going down hill….30 mph. The boat is so broad with an 8 ft beam it travels very rough in any chop at all. My buddies and I primarily wade fish. It is an excellent platform to move 4-5 people into very shallow water. There is no perfect boat. This one suits my needs very well

[rick berrey]

Dr Pete , I used to live in CC , so I know a tailwind is about 25 on a good day when you can keep your hat on . We ran 90,s on our 24' Carolina Skiff work boats , a 120 on a 28' Alu. flat bottom , broke the welds in that one . And riding in a flat bottom boat in light to mod chop broke me from ever wanting one . They are nice on flat water and for payload but my back cant take a rough ride anymore . I remembered the xf20 study plans called for a smaller motor and thought the added speed and weight of the motor on the stern might affect the performance .