design feedback

[ieagreg1]

Hello everyone,
I was hoping to get feedback on the design of this boat its a 21' barrel stern runabout with a 1920's style bow. It's powered by a 3.0l 135hp I/O it handles well and is quite fast for being underpowered. I designed and built this boat myself it is my first attempt. The one thing I have a problem with is everyone that see's it tells me how great it looks and I'm not sure if theyre just being nice trying not to hurt my feelings. My plans are to possibly build 1 a year as I enjoyed this adventure very much. But dont want to build a dog and end up with a back yard full of these no one wants. Harsh and truthful views are more than welcome.
Thank you in advance for your opinions

[cyclops]

Why did you put the sterndrive stiffner plate on the outside of the hull. It really is better looking if mounted on the inside. There you can make it as thick or large as you wish. Other wise, it looks great.

[ieagreg1]

The sterndrive was an after thought. I was going to use a jet drive but changed mid stream. I wanted to get this in the water before the end of the season and this was the fastest alternative. This winter I'll deside on what to do about the power and the transom.

[KCook]

For big waves I would be concerned about the bow getting buried. Should be fine as is for cutting modest chop.

Does the "barrel back" code really require a circular stern section? I would be tempted to tone that down with slightly flatter sides and top.

Neat theme for a small custom boat though,
Kelly Cook

[cyclops]

I regularly ride this type of hull. The "cleaver bow" as it is known, has a fantastic ability to cut a soft gentle hole right thru a 4' to 5' wave so smoothly that it makes all modern bows into white knuckled monsters. That is why they had such massively strong metal windscreens. My 19' bow rider is airborne on all waves over 2' at more than 40 mph. At 50 mph I grab the top of the windshield with both hands, lower my head and close my eyes till I land. I never feel the need to do that in a cleaver bow because it never flies in the air.

[cyclops]

I agree with KCOOK on the round stern. Too severely round. Look at more barrel backs. Or stay as is. It is your design.

[Gilbert]

Hi,
I bet just about everyone wishes their first design turned out so nice. I think the outdrive detracts from it's classy appearance. It would better fit the average persons expectations if it had a conventional inboard. You might try tampering a little with the round section of the barrelback as others have noted. But my only real criticism is that you need to put a new net on your basketball hoop.
Good job.
Gilbert

[LP]

In regards to the barrel back, I like the amount of tumblehome on the sides. I would tone down the curvature of the aft deck. Having a smooth transition from highly curved sides to standard deck curvature would look ideal. Or you could just do away with the whole afterdeck like this little gem.

http://www.svensons.com/boat/?p=HydroPlanes/Flyer

Personally, I view wooden boat construction as an artform and as such, as long as you combine good looks with structural durability and safety, anything goes. Wood and varnish (and epoxy) are the medium. Throw in a little technology and you've got a living, breathing sculpture.

Curious though, did you do a constant dead-rise hull and spray chines or did you go with a traditional planing afterbody? What kind of wood did you use for the deck? Epoxy construction?

Since you are looking for criticism, while I like the light wood on the deck, there is almost too much contrast between it and the kingplank and covering boards. A darker deck or lighter kingplank and covering boards would make the contrast a little less stark. This is only my opinion and I am by no means an expert. I'm contemplating a similar deck on the runabout that I'm building.

It looks like you did a great job. I'll be anxious to see it when trimed out. I little more chrome, maybe?

[ieagreg1]

learpilot,
The hull is based off of a riviera although knowing what I know now I would have gone with more of a deep v. The hull is mahogany framed with 1/2 ply and the sides are 1/4 ply then 3 alternating layers of mat and weave fiberglass then the sides are planked with 3/16' hoduras mahogany the bottom is bare fiberglass as well as the covering boards. The mahogany on the deck is 1 x 2 clear mahogany you can buy from menards. It work out nice no ripping just trim the ends to fit. I agree with everyones sugestions of toning down the aft deck this is a battle I must fight with my girl friend as she likes it the way it is and so far hasnt given in. And yes there is going to be alot of chrome rubrail, step plates, windshield brackets, ect.

[Raggi_Thor]

Maybe the chine could be a little higher in the front?

[cyclops]

A happy woman behind the wheel is a "good thing". Can you afford to do another boat with the changes? Lay off all the fiberglass. Glue, wood, stain and varnish do the same and are better for a all wood boat.

[LP]

I agree with cyclops. I happy woman behind the wheel is a good thing. :p

[KCook]

Maybe the chine could be a little higher in the front?
My thinking as well. I still worry about burying that chisel bow. How are the sea trials going?

Kelly

[cyclops]

Burying a bow on a vertical bow is no life or boat threatening deal. The wave is split apart, not pounded apart like a modern runabout. You have to drive one to understand that.

[ieagreg1]

The sea trials went well but short due to a bearing failure in the cobra sterndrive but when it was running it was fine steady and smooth, it leaned into the turns nicely but the bow was a bit to high will probably need trim tabs to bring it down. It will also be very ruff in chop with the relativly flat bottom. This boat will spend most of its time on lake michigan where pounding thru the waves is not advised unless your running something like a 40' plus cigerette. The waves here can easily reach 3 foot (great for jet skiing). The sterndrive is fixed and will run it again this weekend with any luck.

[cyclops]

This boat is teaching you a great deal in the flesh. It is worth it's weight in gold. After you find the short comings, I am sure the girls wiil love it to death. Knowledge and happiness in 1 boat. Put a VHF radio in for safety and the girls will MAYBE, see you for meals.------------ I am assy. a 2 seat gentleman's racer. 19' X 4.5' constant 28 degree deep V with a vertical bow. Compare notes next spring - summer. It has the hull form of a small Thorney Craft PTB, (British).

[Tim B]

I thought I'd posted a reply on this thread, but obviously I didn't... The outdrive should have some trim mechanism, if it doesn't or it's at max travel, try moving some weight right up to the front and see if that makes much of a difference. Run-abouts usually were in-borad mid-enginged boats, so many tend to have a lot move volume at the bow than modern powerboats (aft-engined). If you can't move enough ballast, then fit the trim-tabs, but tabs are not usually added to a stern-drive boat to get it planing.

BTW, cyclops, are you sure you mean 28 degrees??? 0 to 8 for a run-about, 18 to 22 deep V, but no more than that.

by the way, there is a good discussion on design features at

http://forums.boatdesign.net/showthread.php?t=8468

and

http://forums.boatdesign.net/showthread.php?t=8468&page=5

for a picture of a nice deep V varying deadrise hull.

Tim B.

[cyclops]

It is a 28 constant V. Extreme, yes. I decided I wanted something that did not buck back on a choppy day. 350 Chev, a trans, shaft and a prop followed by a DEEP spade rudder to stop the bow from hooking. I will line up a Jersey Skiff driver for the first couple of flights. They are the drivers with the best steering and handling reflexes alive.

[lewisboats]

Something was mentioned about the tumblehome being a tad much. Here are a couple that meet or exceed (first and last pics).

http://duckworksmagazine.com/05/columns/max/11/index.cfm

Steve

[YankeeBoater]

That's your first cut? Very impressive! :) How did you model the shape and get such smooth, accurate cross sections?

An aesthetic comment - the transom I agree with making it less semicircular, and I think would also look nicer with the vertical being less vertical - sloping either forward or back. There should also be some taper in width of the transom down towards the waterline. From the transom forward the boat is so sleek - you need to match that to some extent at the transom as well for the styling lines on the whole boat to flow together well - right now it looks too abrupt, like a different boat right at the transom.

All that wood looks beautiful - cannot beat wood as a material for elegant appearance. :)

[ieagreg1]

Just a quick update, the stern drive is gone! Never again will I deviate from my original idea (to save money). I'm converting to an inboard. And yes I'm going tone down the tumblehome. I will post picks when its complete. And thank you all for your replies.

[Raggi_Thor]

Shelman makes a very good Okoume plywood, BS1088, Lloyds serticate, 15 or 25 years warranty, fungicide in the glue.

Se this discussion, Shelmarine vs Bruynzeel:
http://www.woodenboat-ubb.com/cgi-bin/UBB/ultimatebb.cgi?ubb=get_topic&f=1&t=010227&p=

[Raggi_Thor]

uuups answered to the wrong thread :-)

[ieagreg1]

Here's a couple of photo's taken earlier this summer. Your suggestions made all of the difference. She is now sleek and smooth.
Than you all!
Anymore suggetions?
She should be complete spring of 07'

[LP]

Looks great! I like the the windshield. Do you have a better picture. Where did you find it and the chrome rub strip. I'm in the midst of a similar project.

[ieagreg1]

LP,
The windshield frame is a riviera reproduction I bought off of ebay. I'll take some close up pictures. The stainless is from a 36' Chris Craft that is being salvaged. West marine offers a hollow back stainless at a resonable price but if you can find an old chris that is being broken up that's your best bet. The solid backed stainless I'm using cost me about 50 bucks. Do you have any pictures of your project?

[Wayne Grabow]

You have a beautiful boat. I think that you have received some excellent comments, but, in the end, it is your boat, your bit of artistry. I notice that you commented twice that you wished it were more of a deep "V" design. If you plan on repeating the build of this boat multiple times, you might want to change that. Of course, a deep "V" will take more power. What is the angle of deadrise at the transom? I like the tumblehome and deck camber but find an overall elliptical shape more pleasing than your almost circular transom. Changing the deadrise (which will also affect the bow shape) and relative dimensions of the transom may be more than you want to undertake. It is a nice design already. Your posting has encouraged me to get back to work on a runabout design I have been considering. Thanks.

[LP]

Ieagreg1,

Sorry to take so long in getting back to you. Here are some pics. Hope to get it wet this summer, but I'm afraid the finances will make me wait another season.