View Full Version : Handy Billy 18 Explodes (or not)!

Dan Nielsen
08-11-2006, 12:16 PM
Sorry about the mis-leading headline, but it got your attention.

Last Friday I launched my HB 18 for 'lake trials'. She was 100% complete, but by the time I reached the lake her motor cover went missing, so now she is down to 98% complete. Thinking in terms of water speed, no latch cover is required. Thinking in terms of highway speed .... well, it seems obvious now.





I hope these show up or you can get at them - I don't get along with computers very well.

She has a 20 hp four stroke Honda and puttered around nicely. I observed that at full speed, about 13 mph she rides with here bow sticking in the air pretty high. The helmsman can easily see over her bow, but from the rear thwart all you see is bow, sky and the back of my bald head. I understand that this is characteristic of this type of hull.

However, she still seems bow light. When my 200 lb companion moved aft, she lost 1 mph. When he crawled out onto the bow, she speed up 1 mph. Now, to the exploding part. I am considering moving the battery (with its 30 lbs) from under the aft seat to the forward compartment - where the fuel supply is. The fuel tanks are low and the battery would be high. The forward compartment is passively vented around the perimeter of the bulkhead. Opinions please.

I do not have a tachometer, but I suspect my prop may be taking too big of a bite at 10 inches (9-1/4 x 10, four blade). I am tempted to blindly try an 8 inch pitch. Any thoughts on that.

I realize she is not intended to be a fast boat, but I do want to get all she can offer (within reason). Harry, the designer, said he got 15 mph out of the HB 18 with a 15 hp motor. I know, I know - Harry can certainly build a boat better than I, but I think I stayed true to the design. I think there must be a little more speed in her.

She has the 'home made' controls as designed, but I went with rope (opposed to rigid rod linkage) for the steering. During the trials I guestimate she covered about 30 miles and burned a little over 3 gallons of fuel. This will likely change as we were conducting the motor break in.

08-11-2006, 12:29 PM
Very nice boat! Thats one of my favorite designs. How did you find Harry's plans for this boat? Pretty good? I built his Fiddlehead and thought he did a good job with the plans and booklet. Does he give plank offsets or did you have to spile? How much lofting was invloved?

Sorry for the questions, the Handy Billy is on my short list of next builds.

Again, great job!


P.I. Stazzer-Newt
08-11-2006, 12:35 PM
I like that - unpretentious - nice.

08-11-2006, 01:37 PM
Contact Whiffle English by searching for posts under that name on the Forum. He built an HB 18 and would be happy to discuss how he built and rigged his, I'm sure. I rode around on her for quite awhile and made about 9.5 knots WOL per the GPS with three of us aboard (he and I are not featherweights!)

I think he has a smaller engine than yours, however, and his has a center console w/wheel instead of the forward seat with tiller.

08-11-2006, 02:39 PM
Beautiful job!

Tar Devil
08-11-2006, 03:47 PM
That looks like Jordan Lake...



Oh yeah... Really nice boat!!:) :)

John Bell
08-11-2006, 04:20 PM
A tach would be very helpful to figure out what's going on. If you aren't hitting the suggested revs at WOT, then a lower pitch prop is indicated. I'd make sure the motor is giving you full power before you start adding trim ballast.

Adding weight to what is supposed to be very efficient craft seems counter to the whole purpose of the boat, anyway. Avoid that solution at all costs!

Definitely move the battery, IMO.

Dan Nielsen
08-11-2006, 04:26 PM
Thank You for the kind words

Dave - Harry's plans for the HB are not quite as detailed at they were for the Fiddleheads (I built a pair of those). It is two sheets, lines and construction details by plan and profile. It comes with a booklet, but it is by no means a 'how to' document. Owing to the fact that it is a single chined boat, lofting is about as easy as it gets - but still stimulates the brain. The planks need to be spiled and get a little tricky up by the bow near the chine. The series of artcles on building the HB 21 in WB was very helpful. Building this boat was a 700 hour effort for me.

Phil - You are close, but I launched a little further north on Kerr Lake at Steele Creek Marina.

rgbarr - I'll hunt for Whiffle English - thanks.

08-11-2006, 09:14 PM
Very nice boat. Sorry to hear about the motor cover and I second the tach trials advice.It's definitely the only way to tune the prop/engine.

Cecil Borel
08-12-2006, 07:23 AM
Dan: congratulations. She looks great! I admire your productivity.

08-12-2006, 05:51 PM
Thinking out loud here.

The tach is manditory to get the motor in the proper operating range and get the correct prop on it.

Tiny Tach's work well and you get a hour meter to boot. They can make them with and extended leed so that you can mount it by your control.

Another factor is that I belive you have the motor mounted to low. As proved by your buddy moving foward and have less drag on the foot.

Lew Barrett
08-12-2006, 07:32 PM
Looks great. Wonderful job.

08-12-2006, 10:21 PM
Dan, that's a beautiful boat, congratulations. I believe moderate power, efficient designs like HB are going to become more and more popular. 10 mpg is great!

Re the bow high trim (forgive me for stating what may be obvious): 1) check the motor tilt adjustment, 2) as someone just said, check that the motor's cavitation plate is just a hair below the bottom, 3) before you go to the work of relocating the battery decide if it will be worth the effort as your 200 lb crew on the bow only increased speed 1 mph.

Boats with an underbody shape like HB will ride bow high at speed - its the trade off for more efficient low and medium speed operation. You might post a picture of it at WOT and get other HB owners comments


This is a HB 18 with a 15 hp Honda pic from Brion Reiff's web site.

Farmer Diddley
08-13-2006, 05:08 PM

Beautiful boat... you are one talented individual... so when the wind is blowing you take out your Haven 12 1/2... and when there is no wind, you can now take out your HB... very nice indeed!


Dan Nielsen
08-14-2006, 08:43 AM
So Cecil, how is 'the big one' coming along?

Okay, I've heard you guys. I'll see if I can rig up a tach. I am resisting instrumentation for this boat, to be consistance with its appealing simplicity. Might be able to find a tack that will work off an induction coil around a spark plug wire.

I'll also check to see how far below the waterline the cavitation plate is - I think it is about 4 inches.

I hope to get some full speed photos when I can get some boat to boat shots out away from the marina. Folks seem to frown on high speed passes through the marina.

Steve, you are right. The Haven is for the windy days and the Handy Billy for the other days. It seemed to me to be a splendid combination especially for the waters I sail. Both boats were built in my garage and they are similar in size so I can use the same trailer for both. (The Haven lives in the water most of the time). Throw in a pair of Fiddleheads when you want to take a peak at nature (got good and close to a Great Blue Heron yesterday - what a sight as she glided inches above the water). I am a fortunate man.

08-14-2006, 09:06 AM
I'll also check to see how far below the waterline the cavitation plate is - I think it is about 4 inches.

AFAIK that's been a (slight) difficulty with the HB motor wells and engine installations. They were designed for short leg (15") outboard engines, and then the manufacturers stopped making new smallish four strokes in that size, which is what most owners and builders seem to favor. If you raise the motor mount in the well for the available 20" leg the motor cover rises that much higher above the aft deck, the engine hatch becomes more pronounced and higher, the outer transom opening has to be taller to clear the tilted up engine, etc., etc., etc. It's a compromise. I imagine most HB owners/builders choose aesthetics over 'top speed'.

Garrett Lowell
08-14-2006, 01:36 PM
Showoff! First a Haven 12 1/2 and now the HB! Nicely done, Dan.

08-14-2006, 02:49 PM
Great stuff. I love that foredeck cleat. Such a sweet, wholesome boat.
Get the trim sorted out (she does appear to be dragging her tail a bit) and have a blast!

08-15-2006, 11:11 AM
The cavitation plate definitely cannot be that much lower than the hull bottom. Should be at or a red one below like stated.Not to mention is more susceptible to damage from submerged hazards.

Beautifully detailed boat. Looks great.

Dan Nielsen
08-15-2006, 05:05 PM
I spoke to the boat store where I handed over a king's ransom to procure my outboard. For $25 they can rig a temporary tach. Then it is off to the lake to see what she doing and figure out if I need to change the pitch of the prop. I understand the speed will increase 200 rpm for each inch of reduced pitch.

So, nobody seems concerned about putting the battery up front with the fuel. Have I got that right?

08-15-2006, 05:53 PM
So, nobody seems concerned about putting the battery up front with the fuel. Have I got that right?

Any slight advantage you get could be minimal for the expense (longer, perhaps heavier cable, newly crimped battery lugs, cable wire ties and labor to secure against chafe, etc.) Just for a few pounds of moment gained? Not likely to be a noticeable improvement in the end imo. Try a bag of sand up forward that weighs as much as the battery, or more, to see what difference it makes first.

Dan Nielsen
08-16-2006, 08:31 AM
I took a few measurements last night concerning the motor. The cavitation plate is 6 inches below the painted waterline and is at the same elevation as the bottom of the keel (boat) at the motor transom. Next time I have her in the water I will see where the plate is in relation to the actual waterline. Although, I guess it is what it is and there is not much I can do about it.

As rbgarr stated, the motor is a different shape than the one used in the design. My motor well is 7 inches wider than the designed well. The motor box is also 5 inches taller. In an attempt to disguise the taller motor cover, I made the coamings 1 to 1.5 inches taller and painted the cover sides a dark (hopefully slimming) color. Of course, you can't see this because the cover is in a ditch somewhere along the roads of North Carolina. At first it seemed awkwardly tall, but eventually I grew accustomed to the way it looks.

Moving the battery would certainly be a pain in the butt. I think I'll wait to see how the prop experimentation comes out before I decide whether it would be worth the effort.

08-16-2006, 10:22 AM
Ideally,it should be even with the boat bottom plank itself. When you said 4" below,I thought you meant below the bottom of the boat and I too thought you had installed a 20" shaft motor on a 15" transom.I didnt know you meant waterline.

I dont like the idea of having something that can spark in the same area as the fuel tank. If a terminal was to get slightly corroded it could spark when you go to start up.

I was reading one of the later version od woodenboat magazine where they had a story of that powerboat with the JD tractor seat and the builder had added 200lbs of weight in the boat to improve performance. After the tach/prop issue is addressed, you could always experiment with adding/moving weights around such as a couple 5 gal buckets of sand or whatever to determine if tuning the hull with ballast might make the boat more comfortable for your usage.

08-16-2006, 10:46 AM
My engine came from a pontoon boat with a 12x8P prop. It dogged the hell out of it and motor wouldn't develop even close to operating RPM's. I changed it to a 10" dia. x16Pitch prop and she overrevved albeit fast and much better performance so I need something in between,ideally, or to watch the tach to not go beyond redline. The reduction of pitch/higher rpm scenario only holds true if the same diameter prop is used. That was a confusing dilemma for me as I couldn't get a lesser pitch than 8. So what they don't tell you in the prop selector charts is that pitch is also proportional to diameter. In my case,lessening the diameter 2" and doubling the pitch was the opposite effect and I have too high of rpms with double the pitch. I thought only lessening the diameter by 1/6th and doubling the pitch was going to be worse than what I had with the huge prop going by what was stated about the rpm per pitch ratios.

08-16-2006, 01:49 PM
I don't know what the calculations would show, but having a wider motor well opening on the bottom reduces the hull's 'bearing surface' (?) and volume, which may lead to more of a squat/bow up attitude at speed than you want.

Dan Nielsen
08-16-2006, 05:03 PM
Yeah, I thought about the lost boyancy as well. By my calculations, the surface area lost is 7"x 36" or about 1.75 ft sq or about 9.3 lbs per inch of emersion, not discounting the 'weight' of the missing wood. There is not a whole lot of emersion back there maybe two inches. So the lost is about 20 lbs. This coupled with the heavier motor than the design motor which is about another 20 lbs, you end up with about an rough equivalent of 40 extra lbs at the aft end.

Not a huge amount, but this is a small boat. That is why I've been considering moving the battery forward and getting it on the other side of the center of mass. I would rather avoid adding 'dead' weight up front for balance. But if adding dead weight will improve performance .........

sv Lorelei
08-16-2006, 05:29 PM
Dan, I've been thinking about this and I figure that if it were me, I'd put the batteries up front but put 1/4 inch bulkheads between them and the fuel tank. I'd also vent the battery compartment high and low just to give the off-gassing someplace to travel.

08-16-2006, 07:56 PM
Nice boat you have there.

I was disappointed with the performance of my boat with a Honda 30-hp a few years ago. Eventually I took it to a Honda dealer and explained my problem. They made some adjustments and now it is OK. Evidently the adjustments are due after the engine is broken in. I would estimate the improvement was 10 to 15 percent more power. I got a few more knots

08-17-2006, 11:37 PM
Dan, your boat looks great. Sorry about the hatch. Mine is securely fastened. Still have not quite finished it, but getting very close. Will be away for several weeks, so maybe October. It will be so much cooler by then anyway. It was 104 today.

I kept the battery aft; just cannot take a chance on sparking near the fuel tank. Should never have fuel vapor in the area, as it is filled and vented from outside.