Best runabout design for 20hp motor?

[wfcook]

I'd like to build a small runabout for a lake that will have 20hp limit (currently 10hp, but that is expected to change). I would like to be able to take myself and an adult passenger (wife) out to watch the sailboat races, which means we need enough speed to get between the leeward mark and the weather mark (staying out of the race area) before the fleet does. Say 20mph? 15mph minimum, probably. Total passenger weight probably 300 lbs.

Also, I'd like to be able to go out myself and have a little fun, and in the future maybe take a child or two. It might eventually become the kids' boat when they get old enough.

It would seem that the lengthened Glen-L Squirt and the Glen-L Flying saucer are good candidates, although ideally something in between would be nice. I am not aware of any plans in this size range that are not plywood, but I'll accept any suggestions at all. The Squirt seems like it would be a bit tight for 2 people, and the FS seems like it might want a little more than 20hp, and certainly more than 10hp.

I'm a Naval Architect, and I have some resources available to me, so in truth I could design something myself if I had to. But small powerboats aren't really my area of expertise and it would seem that it would be better to at least *start* with a proven design.

What are the best options for power-plant in this range? Are there any waterjet populsion plants down to 20hp?

Any advice at all is greatly appreciated,

BC _/)_

P.S. The lake has a 10hp limit, but legislation is working it's way through the system to raise it to 20hp and I expect it to pass by the time I complete the boat. Also, I have been told by MANY people, including the park ranger (!!!) that most people are running 20hp motors anyway because it shares the same block as the 9.9, and they've put a 9.9 cap on the 20hp outboard unit. It seems that as long as you aren't water-skiing or riding a jet-ski or disturbing the sailors and fishermen, nobody is really concerned either way. My preference would be to be legal, of course.

[Thorne]

Welcome to the Forum!

What sort of conditions might you go out in, and what is the size and location of the lake?

Are you looking for a drop-dead beautiful runabout slathered with varnish, or something more comfy, workboat-like and functional?

[Spokaloo]

Look to Robb White's sportboat:

http://www.robbwhite.com/i/boatfinished1.jpg

It actually will plane your particular payload with as little as 4 hp, and will rip right along with a 9.9 horse. You could save yourself the cost of the extra 10hp! Its no monster, but she has all the qualities you would want in a small workboat with small horsepower and big boat seakeeping for its size.

http://www.robbwhite.com/i/sportboat.talquin.250.jpg

http://www.robbwhite.com/sportboat.html

I think im going to build one someday, if I can just get the project list down to something I can complete in less than a decade....

E

[kc8pql]

This one looks like it would be fun to me. 9 to 25 hp.
http://www.svensons.com/boat/?f=HydroPlanes/DoodleBug/outside_port.jpg
http://www.svensons.com/boat/?p=HydroPlanes/DoodleBug

[Steve Paskey]

John Welsford's RIFLEMAN. A classic look with lapstrake sides, and about the power range you have in mind. Speed to up to 25 kts with 20 hp. A bit longer than the two Glen-L designs (14'9"), but you'd have no trouble taking an adult and a kid or two, and the weight is still modest -- about 200 lbs.

http://www.duckworksbbs.com/plans/jw/rifleman/index.htm

[Thorne]

I suspect he's looking for more of the classic varnished runabout design, but the Rifleman sure is a sexy boat!

[johnw]

I'm thinking Ed Monk's Sunbeam. It's in "How to Build Wooden Boats," by Monk, first published in 1934 but currently in print from Dover for $10.95. Classic 1930s runabout, 14'8" by 4' 9", or there is a 16'6" version that's 5' wide. The book includes plans, offsets, even the lumber order. 16 mph recorded with a 14 hp outboard.

[Spindle]

Check out Glen L .com or Clarkcraft. There are quite a few small outboard runabouts. I am building the Glen L Squirt, 10' x 4' and 120 lbs. they have rated it at 10 hp and have had great results. I have a 1958, 18 hp Johnson Seahorse that I plan to use.

[Keith Wilson]

Here ya go: John Atkin's Russell R. Plenty of space, plenty of speed, easy to build, good-looking, and the outboard is in a covered well so it's nice and quiet. http://www.atkinboatplans.com/

http://www.boat-links.com/Atkinco/Oar/images/RussellR-1.gif

http://www.boat-links.com/Atkinco/Oar/images/RussellR-2.gif

http://www.boat-links.com/Atkinco/Oar/images/RussellR-3.gif

[pipefitter]

I think that something along the lines of one of the Garveys would be great for 20hp. Runabout seems to cover a lot of styles these days but for something that is stable and will still fly on demand, one of the smaller planing hulls would be great for such. Here is a 14ft version of the Simmons Sea Skiff shown with a 10hp if I recall correctly. I think this fellow also posted some pictures of the boat getting along faster than this picture shows.

http://www.simmonsseaskiff.com/Gallery/baccellieri05.jpg

Another good boat might be Payson's Diablo.

[MiddleAgesMan]

Phil Bolger's Diablo--15' 6" by 5' wide, hp up to 25 or so but they plane easily with 10-15.

http://www.kolbsadventures.com/assembled_upright.jpg

Edit to add--that is not my skiff but is one of many construction photos I found here: http://www.kolbsadventures.com/assembled_upright

I had intended to just post a link but decided to try adding the img thingies to see if it worked. It did but I just realized it gave the impression that was my boat.

[mcdenny]

If you like the Diablo here's my son-in-laws website with lots of pics and video of the boat he & I built a couple of years ago.
http://www.dropsheet.com/diablo/html/index.php

[JBreeze]

Another for consideration:

http://www.bateau.com/studyplans/FS14_study.htm?prod=FS14

http://www.bateau.com/prodimages/FS14_350.jpg
\
Might be too fast with a 20hp, though....especially for the kids when they go solo.

[Steve Paskey]

For another wrinkle from the vast catalog of Wm. and John Atkin, here's QUICKSTEP ... a 14-foot lightweight, high-speed runabout that does NOT use plywood construction:

www.boat-links.com/Atkinco/Oar/Quickstep.html

She was designed for the "CU" racing class, which used outboards of 30 cubic inches. Atkin estimates that she might approach a top speed of 45 mph. (For what it's worth, something around 33-34 mph was good enough to win the CU class races held in conjunction with the President's Cup on the Potomac River in 1953.)

Does anyone know what would be a comparable outboard today?

[Steve Paskey]

I suspect he's looking for more of the classic varnished runabout design, but the Rifleman sure is a sexy boat!

You're probably right, but until he tells chimes in with that anything is fair game.

Any minute now someone will toss out Bolger's FASTBRICK as a suggestion ... And I'm still waiting for someone to post the photo of the upside-down dining table with an outboard attached. :D

[kc8pql]

She was designed for the "CU" racing class, which used outboards of 30 cubic inches.
Does anyone know what would be a comparable outboard today?
Nissan has a 30 cu. in. (492cc) 3 cylinder 4 stroke rated at 30 hp. Don't know how that would compare to an old 2 stroke though.

[johnw]

Here's a link to the pages of Monk's book that show the plans for two outboard runabouts. He's not well known outside the Northwest, but he sure drew some nice boats.

http://books.google.com/books?id=BfSmqiXF06gC&pg=PA45&lpg=PA45&dq=edwin+monk+runabout&source=web&ots=KnOWQigYfm&sig=u_30W88zmLPjYrX-X9fBugnx4XE&hl=en#PPA45,M1

[bloggs68]

What about Ken Workingers Dad's ol Outboard skiff as featured in Small Boats magazine?

Here's a pic on the builders website.

http://www.greatwoodboats.com/usedboats/usedboats.html

regards,

AD

[AngWood]

Gotta love Tom Hill's Long Point: http://www.thomasjhillboatdesigns.com/the_long_point.html

[wfcook]

Wow, this response is amazing! Thanks to everyone for the very warm welcome to the forum and for the advice.

Thorne is right, I am aiming for something fairly traditional looking. Something that is a sort of caricature of a larger Chris Craft or Hacker would be ideal, which is why I gravitated to the Glen-L Squirt and Flying Saucer. HOWEVER:

Should I decide to design something on my own, it is good to know about ALL of these designs. I'm capable of doing all the design work at a fair level of sophistication, but not naive enough to think that I wouldn't benefit from seeing the parameters of proven designs. In an ideal world, somebody has already designed something very, very close to what I want.

I notice that many of these designs have very little deadrise, particularly aft. Is porpoising or hard slamming typical for these things?

Thanks again, this is great stuff. I am going through it all now.

[Spokaloo]

I think you will find that the majority of the designs with warped plane or double wedge hulls don't pound because they dont move at speeds over 20kts. Keeping their forefoot in the water and traveling at S/L of 2ish at least reduces the likelihood of pounding. Granted, in the right sea state you will in anything without a true V, but then all your efficiency goes out the exhaust pipe losing all that lift.

E

[wfcook]

Very well put, Spokaloo. I will keep that very much in mind. It's a lake, so I'm not too worried...more curious.

[jerry bark]

I notice that many of these designs have very little deadrise, particularly aft. Is porpoising or hard slamming typical for these things?



I have a small tiller boat with a 30 hp (not wood) that runs 24 mph at wide open.

it has a small deadrise ~7 degrees or so. it does not porpoise or pound until the waves get above 1.3-1.5 feet. even then its not bad as long as the load is balanced. If i am by myself its much worse than if i have a friend along. my guess is its because the extra weight up front keeps the deeper deadrise of the bow down in the water to cut through the waves rather than have the bow go right over so the wave hits 1/3 or more back on the bottom.

So, my experience would be that you would not mind in moderate conditions if you have the load balanced and a deeper (finer?) entry.

cheers
jerry

[Spokaloo]

Jerry, just as a little comparison, I have a 1500 pound, 22 foot long warped plane/double wedge hull with only 20 more horsepower (50) that runs at 30mph with just me at WOT. If I keep the fuel tank full and put my fishing tackle, anchor, and cooler in the bow, she never pounds as the deep forefoot slices away the bumpy stuff.

Please bear in mind, Im just bringing that up to show how efficient a hull can be if her intended purpose is met, not denigrating your skiff in the least.

E

[johnw]

I have a small tiller boat with a 30 hp (not wood) that runs 24 mph at wide open.

it has a small deadrise ~7 degrees or so. it does not porpoise or pound until the waves get above 1.3-1.5 feet. even then its not bad as long as the load is balanced. If i am by myself its much worse than if i have a friend along. my guess is its because the extra weight up front keeps the deeper deadrise of the bow down in the water to cut through the waves rather than have the bow go right over so the wave hits 1/3 or more back on the bottom.

So, my experience would be that you would not mind in moderate conditions if you have the load balanced and a deeper (finer?) entry.

cheers
jerry

I think this is why in the classic runabouts like those Monk designed, the steering station is forward.

By the way, the one I'm recommending is on page 47 of "How to Build Wooden Boats," which is not part of the preview I linked to, but the text referring to it is there and it looks a lot like the 16 footer on page 48.

[jerry bark]

Jerry,
... If I keep the fuel tank full and put my fishing tackle, anchor, and cooler in the bow, she never pounds as the deep forefoot slices away the bumpy stuff.

Please bear in mind, Im just bringing that up to show how efficient a hull can be if her intended purpose is met, not denigrating your skiff in the least.


sounds like we are talking the same thing: proper trim and conditions and such a moderate deadrise will ride fine.

your speed/weight/hp is pretty good! my guess is that my boat/motor/gear weighs ~650-750, using a quick estimate and steering from the rear seat it gets bumpy if the waves are very big and i am alone. with a partner it does well in anything that is safe for the size boat (15').

though i do find that a cooler loaded with walleye helps the balance a bit too :)

cheers
jerry

[Tom Robb]

WoodenBoat's store sells a plan for a sort of TonkaToy "mahogany runabout" 14' Rascal but it calls for a 40 - 60 hp motor - smaller wouldn't be the end of the world. Cute little boat. Someone here built one, I think.
Go back to the home page and click on Store for a look if you like.

[openboater]

bolger clam skiff

Michalak AF4 or AF4Breve

both simple and useful.

[Steve Paskey]

Thorne is right, I am aiming for something fairly traditional looking.

If it's varnished mahogany you want, you can't get more traditional than this:

http://i.treehugger.com/files/th_images/outboard-table.jpg

[mcdenny]

Steve - it only took 14 more posts.

[Bruce46]

Many years ago I had one of the 14' Chris Craft kit boats. With a 12 hp Elgin outboard it would tow a water skier, with a 40 Johnson it flew. I raan that boat on Long Island sound and various bays and it preformed well even in very rough water. James Craft has resurrected the Chris Craft kits. Using one of these kits would save a lot of time and headaches. http://www.jamescraftboats.com/

[P.I. Stazzer-Newt]

Nobody proposing a foiler moth hull and a 20 horse motor?

[wfcook]

Thanks again to everyone for the great advice! I'm still digesting all of this info.

[wfcook]

Many years ago I had one of the 14' Chris Craft kit boats. With a 12 hp Elgin outboard it would tow a water skier, with a 40 Johnson it flew. I raan that boat on Long Island sound and various bays and it preformed well even in very rough water. James Craft has resurrected the Chris Craft kits. Using one of these kits would save a lot of time and headaches. http://www.jamescraftboats.com/

Does anybody just sell the plans to all those little Chris Craft runabouts?

[wfcook]

If it's varnished mahogany you want, you can't get more traditional than this:




Goodness. What is it? In the right context, I bet it's kinda cool.

[stumpbumper]

One more to digest - The Fast Skiff 17 would probably meet your needs as described. Doesn't look too difficult to build and should do what you require with a 20hp.

http://www.bateau.com/proddetail.php?prod=FS17

[Captain Blight]

Using my first post here to chime in with a vote for Wston Farmer's Sundance (http://www.duckworksbbs.com/plans/wf/sundance/index.htm). More of a cruiser than a runabout, but drop-dead sexxai and a good deep boat to keep the chirruns inside. Certainly enough boat to keep them interested.

http://www.duckworksbbs.com/plans/wf/sundance/scantlings-400.gif

Maybe not as easy to build as some of the tack-and-tape models available, mostly due to bottom shape IMHO.

[Steve Paskey]

On a serious note, there's a fellow who calls himself D.N. Goodchild who sells reprints of boat plans from old magazine articles. I have a few of the sailboat plans, and they're very nicely done. Some are buildable from the reprints, others are not, but there's a long list of stuff under the heading "outboard runabouts" ...

http://dngoodchild.com/divide_for_power_boats.htm

[wfcook]

On a serious note, there's a fellow who calls himself D.N. Goodchild who sells reprints of boat plans from old magazine articles. I have a few of the sailboat plans, and they're very nicely done. Some are buildable from the reprints, others are not, but there's a long list of stuff under the heading "outboard runabouts" ...

http://dngoodchild.com/divide_for_power_boats.htm

That's a good resource, I went and ordered a few designs. I received a CD full of similar reproductions today from advplans on eBay - some of them are the same ones available from Goodchild, so I am aware of the quality of the articles. I've decided to order the 'Flying Saucer' plans from Glen-L as well. While I don't think I'll build exactly that, it's pretty close and I am sure that I can amalgamate something right for me using that as a starting point and the other designs for ideas. I am a Naval Architect, so I might as well start using all those years of schooling for something.

Thanks again,
Bill _/)_

[Steve Paskey]

That's a good resource, I went and ordered a few designs. I received a CD full of similar reproductions today from advplans on eBay - some of them are the same ones available from Goodchild, so I am aware of the quality of the articles.

I think you'll be pleasantly surprised by the quality of the DN Goodchild stuff ... they're probably better than what you got on the CD. The DN Goodchild reprints are "repackaged" into small booklets, nicely printed in two colors, and the reproduction of photos and drawings is very high quality.

Good luck, and keep us posted!

[wfcook]

I will definitely keep you all posted, and thanks again for the help. I am looking forward to receiving the stuff from Goodchild.

I mentioned to my boss (also a Naval Architect) that I couldn't help myself but to want to modify the design in some way, and he jokingly said he thought that pride more or less *required* me to do so. Since I don't do much work on very small wooden runabouts, it will be nice to have a wide variety of designs to look at and keep me anchored in reality.

Bill _/)_