shovel noes tunnel hull! ???

[Jimboat]

Hi Andrew. I got your PM and have emailed you back.

Tunnel Hull technology is pretty well established. If it's a planing hull performance that you are after, then a true tunnel hull design may work well for you. Here is an article I wrote, that outlines basics of tunnel hull design. There are other technical articles that may be of interest to you at: aeromarineresearch.com

Call, email or PM if you wish to discuss.

[firth_andrew007]

please dont hesitate to tell me how much i suck at 3d moulding haha this is my first go at it but it is to scale and it gives the basic structure of the deck maybe all the weight at the bow might counter act the outboards..

[SamSam]

Originally Posted by firth_andrew007

samsam thanks for your advice!
i will deffinently look into this subject thank god its such an easy thing to induce air into the tunnel.. several skin fittings two inlet lines and ball valves.

villageidot cheers for your imput! that is a great idea i could do it in a way where i skip lamination on the tunnel and fair in the new shape after the release : )

You could vent it with an open tube starting high on the transom, going through into the tunnel and then up to the front of the tunnel, no valves or checks.

You could make the tunnel hull, test it out and then fair in the new shape right over the tunnel and test that out. It might save re-rigging a new boat, or building a second boat. If it worked, you could possibly cut open the top of the tunnel and hinge it for some kind of storage, depending on how well or permanent you made the "new shape". If you did it this way, i.e., covering over the existing tunnel, the new shape would not have to be as structurally correct or strong for testing performance. The tunnel would be Plan B, in case the new shape piece fell off or leaked while testing.

A yard where I worked made 12 x 30' power boats and if I remember correctly, they used somewhere around 4-5 barrels of resin in a hand layup of Fabmat, a combination 1 1/2 oz mat and 24 oz woven roven. That was just for the bare hull with no reinforcements like stringers, bulkheads etc. The difference in the amount of resin depended on the experience of whoever was building it. It's not only the initial expense of the extra barrel of resin, it's like hauling around a useless barrel of resin for the life of the boat and they're heavy.

[SamSam]

Originally Posted by firth_andrew007

please dont hesitate to tell me how much i suck at 3d moulding haha this is my first go at it but it is to scale and it gives the basic structure of the deck maybe all the weight at the bow might counter act the outboards..Attachment 25436

I assume you know the hull shape will not look like that?

It also looks like with all that second deck structure the extra flotation of a non-tunnel hull might come in handy. I'm just supposing, I don't really know.

You say the tunnel isn't for shallow draft but extra speed, do you have any idea how much extra speed you get?

[Jimboat]

Andy - here is a picture of a recent hull of tunnel hull design configuration, similar in size/function to your drawing in #17.

[firth_andrew007]

Originally Posted by SamSam

I assume you know the hull shape will not look like that?

It also looks like with all that second deck structure the extra flotation of a non-tunnel hull might come in handy. I'm just supposing, I don't really know.

You say the tunnel isn't for shallow draft but extra speed, do you have any idea how much extra speed you get?

haha yeah i got lazy with the hull its nothing like real thing.. im soo busy atm building small parts/ doing a cert IV in business researching i didnt want to waste to much time on it.

but no im not exactly sure about how much extra speed ill get from the tunnell im really just going off information i have heard of other people so nothing is set in stone with this hull i could be way off mark with is purpose? deff safe to say hull design is not my forte i really do want to study hull design but the courses atm are beyond my cash flow...think around $75,000- $90,000 it what ill be paying to be a naval architeck