Looking for hull design opinions

[dsignr]

I would like to submit this hull design to the forum. I'm looking for comments or any suggestions. This design is for a model boat (1 meter, IOM). It is a maxsurf file. I have being working on it for a while. I have built a couple of boat from plans and now I decided to design my own. I have done some research and I have followed the IOM class rules.

[bhnautika]

Dsgnr I had a look at your design. Iam afraid I don’t know much about this class but I would like to make some suggestions. The models waterlines don’t seem to fair, You could stiffen up the lines to make them smoother by changing the longitudinal stiffness up, to match the number of columns you are using. Be aware that this will change the sectional shape a little. Also I think your centre of buoyancy is a little to far forward at 50%.

[dsignr]

I realized that my center of buyancy was to far forward after I made many this post. I moved it about 53%. I'll work on the lines and make them stiffer. I really appreciate the responce. I'll make a few changes and post the new drawings.

[messabout]

Dsignr;
If you are interested in something that differs from Venom or similar , take a look at the US1M new design called Broadsword. It is more than 14" wide just ten inches forward of the transom, and maximum keel depth is at about 10" aft of the stem. It is said to be a "killer" meter boat that can plane in light air. Not sure the design will fit the IOM class but it's worth a look.

[dsignr]

messabout,

I'll definetly will take a look at that US One meter. The US one meter guidelines are wide open. There is hardly any limitations in comparason to the IOM.

I'm attaching new files if anyone is interested.

---I tried looking up Broadsword design on the web but had no luck. it would be great if you knew of any link to take a look at that design.

[bhnautika]

Dsignr New hull is much smoother. Why have you got the forward sections so deeply immersed, this tends to push a lot of volume forward. Have a look at the curve of areas

[dsignr]

I have no specific reason. I have being playing with the numbers that I have as guide lines. Here are some of the guidelines:

max. displacement: 4kg (the keel+bulb can not excide 2.5 kg.)
lenght: 1m
max. Draft: 60mm

my guide lines:

I what to keep my prismatic co. around .44 or .45.



With that said. I have being trying to find information about the target area for the center of buyancy.

[dsignr]

I made a fee changes in the over all shape. It seems smoother much smoother. I'll appreciate any comments

[longliner45]

Iam not a designer .but just ran a thread on what types of boats designers have ,most were classical design,,,,,low to the water ,deep and heavy keels nice lines ,maybe something to that......longliner

[dsignr]

I actually own and Bristol 29.9 1979. It is in fact a deep, heavy, classical boat. Great for cruising and you can't beat the space it has for a 30 footer.

[bhnautika]

Dsignr Your LCG and coefficients look good,keel line to. I would render the hull with Gaussian Curvature, with the brightness level at 3. Just to see where the curves and flat spots are and where they join.

[dsignr]

bhnautika,

I realley appreciate all the help and time you have given me and I would like to thank you. I'll keep posting my process. I definetly take a look at the Gaussian Curvature. It will be a while but I eventully will build the boat. The next steps will be to add the fin, rudder, bulb, and design the deck.

[messabout]

Dsignr;

Broadsword was described in the most recent issue of Model Yachting (the AMYA publication) There may be information in the US1M section of the AMYA site. Try AMYA.org. If you dig around that site you may be able to find the contact info for Jim Linville. He is the guru of that class.

You want a Cp of .44 to .45 ????? That is going to make the boat have very fine ends, wherupon it will pitch like hell. Pitching will be further augmented by the pendulum like fin and bulb. The EC12 guys and other sailing modelers are really into this phenomena, even to the extent of doing serious Zamboli tests. Model hulls that pitch, roll, yaw are not fast because it raises all kinds of trouble with sail performance. It will also make the skipper question his ability if not sanity. Try for a more conventional Cp, like in the low or mid 50s.

For what it's worth there are some extremely fast flat bottomed skiffs that sometimes embarass models of more sophisticated form. Typical Cp of .53, .54

If you are a very competant RC skipper, then try to design a better boat. If you are an entry level or intermediate level sailor, just keep the boat simple and practice your technique and tactics a lot. Then you'll know more about what you really want, what works, and what does not.

[dsignr]

messabout,

I made a typing error. My target PC is .545. Right now it is about .548. When I first read your message I was confused be case I thought that my target cp was a mid range. They I went back to my old most and realized my mistake. Had you had a change to look at the lines? Thank you for the comment. It keeps me on my toes.

[dsignr]

Here is my latest file. I added the deck. I had a hard time doing that. I built it in three pieces. I tried to bond the edges but I had no luck. I could bould the whole place on to but then I could not get the hard corners (edges) in the middle of the deck. I would appreciate if anyone has a better way to put the deck together and would like to share it.