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Author Topic:   13-footer with E-TEC 40: Top Speed 30-MPH
coores14 posted 11-01-2006 08:43 AM ET (US)   Profile for coores14   Send Email to coores14  
Should I be surprised that my 13 with the E-TEC 40 only topped out at about 30-MPH [while running against the tide, with 20-knot winds and rough seas]? After owning it for a year, I finally took a GPS out with me. It was just me, a half tank of gas, fully trimmed out. I thought I'd be getting a little more speed. It feels fast, that's for sure. The one catch may have been that it was blowing about 20 knots, the water was pretty rough, and I was running against an outgoing tide. Any thoughts?
jimh posted 11-01-2006 09:13 AM ET (US)     Profile for jimh  Send Email to jimh     
I was looking for a table of predicted speeds versus horsepower for this model [when running against the current, with rough seas, and with 20-knot winds], but I didn't find one.

Measurements of speed upwind and against the current will be significantly affected by those influences.

The Judge posted 11-01-2006 11:17 AM ET (US)     Profile for The Judge  Send Email to The Judge     
"The one catch may have been that it was blowing about 20knots, the water was pretty rough, and I was running against an outgoing tide. Any thoughts?"

Is this for real or a joke? That is actually 3 catches, not one. Why did'nt you GPS it the other direction? Try it again on a nicer day. Mine will do mid 30's.

coores14 posted 11-01-2006 11:50 AM ET (US)     Profile for coores14  Send Email to coores14     
Bad mood today, Judge? Instead of getting bogged down in being negative about technicalities, why not just state "mine will do mid 30's"?
I did run it the other direction. Not much changed. Against current with a tail wind or down current with a headwind, didn't matter. I wish life could be as simple as yours, but I'm trying to sell the boat and a potential buyer wanted to know the speed. I don't own a handheld gps, so acquiring one at a whim isn't very easy or else maybe I would be testing on any other day than yesterday. Thanks for your input, though.
BOB KEMMLER JR posted 11-01-2006 12:13 PM ET (US)     Profile for BOB KEMMLER JR    
30 mph with a new advanced technology 40 Etec?Throw that dog a bone for sure
LHG posted 11-01-2006 12:26 PM ET (US)     Profile for LHG    
As I have said, everyone with an E-tec wants to know how to get their Whaler to go faster!

I used to have a 13' Whaler, way back when. The little 188# Merc 50 I had on it gave me an easy 45 MPH.

Wild Turkey posted 11-01-2006 02:13 PM ET (US)     Profile for Wild Turkey  Send Email to Wild Turkey     

45 mph in 13' whaler!

I bet that was quite a ride. In anything other than a ripple, I bet it was bone-jarring.

You said it was an easy 45mph, were there any conditions in which you could exceed that?

Wild Turkey posted 11-01-2006 02:20 PM ET (US)     Profile for Wild Turkey  Send Email to Wild Turkey     
Also LHG:

I'll bet you have had some of the fastest Whalers ever...

13' with a 50HP
17' (didn't you have a 115HP on it?)
18' with twin 115HPs
25' with twin 200HPs

Also, all Mercurys .

BOB KEMMLER JR posted 11-01-2006 02:25 PM ET (US)     Profile for BOB KEMMLER JR    
"Also all Mercurys"

*hint* Thats the secret for sure ;o)

The Judge posted 11-01-2006 02:42 PM ET (US)     Profile for The Judge  Send Email to The Judge     
Not in a bad mood at all.

You ask a good question then throw a rock at like "oh by the way that was during a hurricane!" Makes me question whether that was a joke or not. You should have mentioned you did it both ways with no change, I would not have questioned it then. I have actually hit 37+ on a still river with a 1994 40 Rude swinging a 17" SS prop on a jackplate.

RJG posted 11-01-2006 02:43 PM ET (US)     Profile for RJG  Send Email to RJG     
How was that speed measured? I didn't think a 13 would go that fast regardless of engine size, make or model.
GAN posted 11-01-2006 05:04 PM ET (US)     Profile for GAN  Send Email to GAN     
I have a 15sport 1976 with a 40 etec. With 2 adults a small cooler, 6gals of gas and bimini up. It only tops at 29, with a hand held gps. but the 29 feels pretty fast.
PeteB88 posted 11-01-2006 05:55 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
30 is fast enough, don't you agree? My 40 is great Yamaha, and handles loads and lard asses very well - only once did it protest with three big people on board. and me.
Teak Oil posted 11-01-2006 08:18 PM ET (US)     Profile for Teak Oil  Send Email to Teak Oil     
How many rpm is the engine running at WOT and what prop does it have
coores14 posted 11-01-2006 08:42 PM ET (US)     Profile for coores14  Send Email to coores14     
not exactly sure of the prop, honestly. I've never really looked. I do know that it's turning 5500 at WOT, trimmed out all the way.
ryland posted 11-01-2006 09:41 PM ET (US)     Profile for ryland  Send Email to ryland     
2005 150 sport, 60hp merc big foot, 36mph, calm day
brisboats posted 11-01-2006 11:49 PM ET (US)     Profile for brisboats  Send Email to brisboats     
Just seems wrong my 71 13' with a 25hp yamaha, a dinged prop and a dirty bottom hit 22mph with my 235 pounds and assorted crabbing gear last trip out. My old 66 with a 18hp Tohatsu could do about the same speed with a perfect prop and bottom. The 1966 Evinrude Ski twin 33hp my 66 13'came with could push it 30mph with old technology and old crankshaft rated horsepower. Don't throw that dog a bone better just hand it to him I'm afraid he couldn't run fast enough to fetch it.


jimh posted 11-01-2006 11:54 PM ET (US)     Profile for jimh  Send Email to jimh     
I guess I am still not sure how fast the boat is supposed to go in this situation. Exactly what speed is expected from a 13-foot Boston Whaler with a 40-HP motor going upwind, up-current, and into rough head seas?

If a 50-HP motor produces 45-MPH performance, then according to our performance prediction formula a 40-HP motor ought to produce about 40-MPH. All we need now is to get rid of the current, get rid of the head seas, get rid of the head winds, and see how fast the boat will go in those conditions.

Take the boat out for more testing and report back.

2manyboats posted 11-02-2006 06:48 AM ET (US)     Profile for 2manyboats  Send Email to 2manyboats     
Our 13 with 1990 40 evinrude runs about 35 mph.

Our 13 with 2000 25 yamaha 4 stroke about 25 mph

jgkmmoore posted 11-02-2006 04:57 PM ET (US)     Profile for jgkmmoore  Send Email to jgkmmoore     
We had a 13' with a 55 Johnson. Went like stink.....wild ride,and felt like blowover was imminent most of the time.We know it went over 40....but you couldn't see the speedo for the tears in your eyes.Very spooky with just driver in boat.First priority was holding on.We downsized to a 40 hp, and saw 33mph indicated on the speedo(no GPS in those days)with two in the boat.
JohnL posted 11-02-2006 07:26 PM ET (US)     Profile for JohnL  Send Email to JohnL     

What I have experienced with our (shared with a my best friend) 13 footer.

1985 13' sport powered with 1985 Johnson 35 - 28 - 29mph best we could do.

same 1985 13' sport repowered with 2001 Yamaha 40 hp 2 stroke with TNT best ever with GPS 42 MPH. 180lbs man and 6 gallons of fuel slight ripple on water perfect for going fast in a whaler. Very fast for a 13 in my opinion, what made the 13 good for us growing up was 28 mph is a manageable speed. 40 is too fast and not what we want our kids to start with. Our 13' in progress will be powered with a 25 hp motor, as a learning platform.

John L.

andygere posted 11-02-2006 07:33 PM ET (US)     Profile for andygere  Send Email to andygere     
How was speed measured "way back when"? ;>)
fno posted 11-02-2006 07:50 PM ET (US)     Profile for fno  Send Email to fno     
Andy, I think they called them "tabs" or "hits" I don't remember clearly as it was too way back when. I think the speed of a 13' might have something to do with how much you load it down. If it's the Judge and his goofy humping dog, mid thirties. If it's two scrawny kids and a couple of fishing poles it'll do better than that.
Barney posted 11-02-2006 07:55 PM ET (US)     Profile for Barney  Send Email to Barney     
Quote: 2manyboats, Our 13 with 2000 25 yamaha 4 stroke about 25 mph.

You had 6 people in that boat going to Horn Island from the Trawler as I recall. I remember the photo. Barn
jgkmmoore posted 11-02-2006 08:43 PM ET (US)     Profile for jgkmmoore  Send Email to jgkmmoore     
Andy- Speed was measured on a spinny thing at the end of a long rope, depth with a leadline off the bow,and called back to the 'helm'.Windspeed and direction by spittin' on yer finger.This gol-darned GPS thang is a stinkin' MIRACLE!
Bjornas posted 11-03-2006 01:35 AM ET (US)     Profile for Bjornas  Send Email to Bjornas     

Are you sure your GPS was reading MPH? I think most of them default to knots. At least check if it was. 30 knots would put you up around 35 mph ish which sounds very plausible. 30 MPH sounds short for sure.

2manyboats posted 11-03-2006 08:01 AM ET (US)     Profile for 2manyboats  Send Email to 2manyboats     
Barney if you look cloe I think there are 7 onboard jpg&.src=ph
and while I am not sure if it will plan with 7 it will plan with 5
2manyboats posted 11-03-2006 08:03 AM ET (US)     Profile for 2manyboats  Send Email to 2manyboats     
close and plane
sapple posted 10-03-2007 11:26 AM ET (US)     Profile for sapple  Send Email to sapple     
For reference, my 2007 sport 130, merc 40, does 33-35 mph at WOT.
PeteB88 posted 10-03-2007 11:42 AM ET (US)     Profile for PeteB88  Send Email to PeteB88     
I don't know about all these +35 reports. My Yamaha 40 and Classic 13 does a blip over 30 WOT GPS. Old pitot speedo agrees when you can see it. What about that speed limiter lip or curl at the transom? Who'd want to go faster than 30 unless wild child?

Tohsgib posted 10-03-2007 11:58 AM ET (US)     Profile for Tohsgib  Send Email to Tohsgib     
Mid 30's absolutely...40+ I want to see a GPS pic because I think it is impossible. A 15' takes 60hp to do 40+ yet with a 40hp it goes as fast as a 13' with a 40hp. Anotherwords, even if you put a 60 on a 13, the heavier 15 would go faster due to better/faster hull design.
macfam posted 10-03-2007 06:09 PM ET (US)     Profile for macfam  Send Email to macfam     
1987 13' Super Sport w/ 2000 Johnson 40hp 2-stroke w/ bottom paint:
Just me and 6 gal gas and normal gear 34 mph (Garmin GPS)

I thought a new 40 E-TEC would be faster. But, they do have a substantial lower unit, and are heavy at about 240+ lbs.

fourdfish posted 10-03-2007 08:01 PM ET (US)     Profile for fourdfish  Send Email to fourdfish     
What is going on here! An old thread! 40 HP is just that! If it is rated at 40hp why would anyone think you would get more out of it! Get over it!
WellFairFisherman posted 10-06-2007 02:08 AM ET (US)     Profile for WellFairFisherman  Send Email to WellFairFisherman     
Hey Fourdfish....Since you have it all figured out can you explain why the 13 foot whaler hull is limited to a max speed of +or- 30 mph regardless of hp???
Tom W Clark posted 10-06-2007 11:22 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Boston Whaler catalogs used to list expected speeds with different power on each model.

The 1980 catalog lists the 13 footer as capable of 34 MPH with 35/40 HP. I presume that meant the 35 HP Johnson/Evinrude or the 40 HP Mercury outboards, the typical motors avaiable and used on the 13s back then.

The speed listed were achieved under ideal conditions.

Yiddil posted 10-09-2007 11:08 AM ET (US)     Profile for Yiddil  Send Email to Yiddil     
I have a 64 13 sport 12,xxx and a 81 Johnson 35 HP seahorse on her back and wen I open her up shes moving pretty lickity split...being so close to the water and not having a gps on her right now I'd sware she was flying in the 30 range wot but not sure...40MPH in that thing will get me killed in anything but dead calm I would imagine, if you make a steering mistake......I prefer to go 15-25 in her for comfort with three adults in her, thats pretty good...

I guess Im not into speed the way some least not with the 13....I did 60 in my other boat this summer Yamaha Waveraider!!!!! and that was a hoot:) Nearly pulled my arms off:)))) Get the right boat if speeds your game...don't think whalers were designed for much of that!

norsman posted 10-09-2007 07:45 PM ET (US)     Profile for norsman  Send Email to norsman     
40.3 mph with a Garmin GPS on my 87 Alert (Sport) with an Evinrude 40hp (1987).

Glassy smooth, and just me (200lbs+) and gas tanks.

In usual conditions, I get a top end (with the boat loaded with fishing stuff, people, etc) of about 32-35mph.


brisboats posted 10-14-2007 08:20 AM ET (US)     Profile for brisboats  Send Email to brisboats     
So much resistance in fact that it will plane with a mere 9.9 hp and a 200 pound passenger. Try that in a "toon". The hull is an efficient design but was not designed as a go fast boat.


MBAC posted 01-15-2008 01:32 AM ET (US)     Profile for MBAC  Send Email to MBAC     
Can I ask any of you with 13' and 40 e-tec answer please? What props are used? Just got that combo and don't want to play prop swap.

Thank you,
11', 13', 21' Revenge

macfam posted 01-15-2008 07:14 AM ET (US)     Profile for macfam  Send Email to macfam     
Regarding a 40 E-TEC on a 13'.

A couple of questions:
1. Did the speed improve over 30 mph?
2. What is the static trim when the boat is sitting? Because that motor weighs nearly 250 pounds.
3. At rest, and the engine lifted out of the water, how much of the lower unit remains in the water?

The 40 E-TEC would be my first choice for my 13', but I'm concerned about the weight. The answers would really help.


ncy7d posted 01-15-2008 10:14 AM ET (US)     Profile for ncy7d  Send Email to ncy7d     
I have a 68' 13 whaler with a 4 hp 2 stroke tohatsu. I am taking it out friday and I will bring my gps and get a reading. I guessed that I was topping out around 40 mph but maybe it just feels that fast. I will know for sure on friday and post my results
fourdfish posted 01-15-2008 10:16 AM ET (US)     Profile for fourdfish  Send Email to fourdfish     
"4 hp 2 stroke"???
MBAC posted 01-15-2008 03:58 PM ET (US)     Profile for MBAC  Send Email to MBAC     

I just put a non T/T 40- e-tec on my 74 13 and to answers some of your questions.

1. Did the speed improve over 30 mph?

I have yet to put a GPS on it, but with an oversized prop the hull was pretty much maxed out. the nose was pushing into the water and the boat was starting to chine.

2. What is the static trim when the boat is sitting? Because that motor weighs nearly 250 pounds.

I will post a picture here. Look at the 13' album:

I intend to mount a 12 gallon tank under the forward seat for this very reason.

3. At rest, and the engine lifted out of the water, how much of the lower unit remains in the water?

A lot of it, unfortunately. I will take a pic for you.

Binkie posted 01-15-2008 04:18 PM ET (US)     Profile for Binkie  Send Email to Binkie     
What year is your Whaler. Are you running a long shaft motor on a short shaft boat. My 50 year old Evinrude 35 hp will run my 13 footer 28mph GPS with two people all day long.


reely mine posted 01-15-2008 07:53 PM ET (US)     Profile for reely mine  Send Email to reely mine     
i have a 1990 13 sport with a 2006 merc 40 4-stroke tnt and a 18 gallon gas tank with my self 130lb (i'm 15)and a frend 175lb 12 gallons of gas 2 med coolers and fishing gear i max out at just myself with about 6 gallons of gass and thats it i can almost hit 40
macfam posted 01-15-2008 08:08 PM ET (US)     Profile for macfam  Send Email to macfam     
I'll be interested to see the pics.
A local boat has a 13 Sport and a 40 E-TEC and the prop remains in the water when moored.(engine up)
In my area (salt water) that is not acceptable.

Just love the concept of the E-TEC. If it works out, it's my nest re-power.

I'm also interested in the data form a 40 (2-stroke TLDI) Tohatsu. I've heard great things about theat engine.
It's the same idea as an OptiMax in a 40 hp.
Great on fuel and performace.

MBAC posted 01-15-2008 10:02 PM ET (US)     Profile for MBAC  Send Email to MBAC     

Finnaly have a prop that is close... 14"x17" it ran today at 27.7kts GPS at 5,400 rpm. With me (275lbs and 12 gallons) I am going to get either a slightly smaller diameter or less pitch prop. I feel the hull is approaching its top speed, so why fight it? So, I am looking for 28 kts at 5,800. I still have to do some math to get there.

I will end up puting a 12 gallon tank in the front. I put 12 gallons in the front in portable cans for the test. I took a shot of the engine out of the water and the prop does clear the water (with fuel onboard).

I also shot some photos of the waterline, before and after I moved the fuel. BIG diffrence in the way the boat sat in the water.

Great motor at speed, nice and quiet. Rough at idle though, but I read this is normal.

see the 13' album at

11', 13', 21' Revenge

Tom W Clark posted 01-15-2008 10:56 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

Raise your E-TEC on the transom of your 13 by AT LEAST one bolt hole and install a Stiletto Triad II in the 11-3/4" x 17" size (part #22317) and you should easy hit 30 knots.

Tohsgib posted 01-16-2008 11:17 AM ET (US)     Profile for Tohsgib  Send Email to Tohsgib     
Without PTnT my 40 would only do about 32mph. With PTnT I can get 37+.
jimh posted 01-16-2008 01:24 PM ET (US)     Profile for jimh  Send Email to jimh     
The standard seems to be "45-MPH with ease" if you use a 25-year-old Mercury 50-HP motor. Can any of these modern motor retain those old days of glory, when speed was measured by...oh, wait, what was speed measured by back then? Certainly not GPS. Probably not by RADAR. I wonder how people knew when they reached 45-MPH back in the good old days? Running on a timed course?
Tohsgib posted 01-16-2008 01:32 PM ET (US)     Profile for Tohsgib  Send Email to Tohsgib     
Heck no Jim...they used a line with knots on it just like Columbus did in 1492. Some actually raced a Greyhound that was on the beach. They know a Greyhound tops out at 43mph so since they beat it by a slight margin...45 was conservative. Some used the reliable pitot speedo from Teleflex for $19.99 that had a 15mph+/- margin but who needs to consider was expensve. Lastly is the ole reliable itself...The Levis "Seat-O-The-Pants"...remarkably some have attained over 50 mph with this medium of ABSOLUTE accuracy.
Binkie posted 01-16-2008 02:38 PM ET (US)     Profile for Binkie  Send Email to Binkie     
I have a pi tot speedo on my 13 footer, and it runs the exact same speeds as my GPS, over about 24 mph. Both say 28mph wide open The speedo is slower at slower speeds.
MBAC posted 01-16-2008 02:41 PM ET (US)     Profile for MBAC  Send Email to MBAC     
Well I got MAD about the lackluster performance of this boat as many here are going MUCH faster than I am. I will not be #2! So, I decided to get more performance out of this 13’. After four hours on the phone I think I can get this thing up to 60kts.

I dug in and called Boston Whaler and after being switched to 6 different people in their engineering department I finally got a hold of an old fella named George who helped with the work on the 13 way back when (he was just a kid then on the production line). He was hard to understand, but he gave me a part number for an OEM refit kit. This apparently is a small mold you can use in the field to form the hull to take out the speed limiting “lip” on the 13’. I then had to speak with the order desk and then the inventory manager. They spent about 20 minutes looking for the part. It was not in the computer, but the old fart insisted… So they went looking in the old index card inventory. ALAS! They had one in the warehouse. After about 2 hours on the phone I was able to order it. After, of course, I signed a waiver. So, I plan on removing everything from the boat, flipping it over in my shop and cutting off the lip, re-glassing with the new mold and gel coating, etc.

Boston Whaler P/N: 13LPREM

Then I called Evinrude and they had many things for me after a similar experience with their engineering department. They came up with the following items for me:

Hi-performance lower unit (all carbon fiber)
Hi-performance prop (again all carbon fiber),
P/N: 8x30 Carbon IV DRAG
To make sure, I got the optional nitrous oxide kit from Evinrude (made by Mercury, of course)
I had to get a new computer for the engine to handle the increase of RPM to 10,000.
P/N: HP Comp 40 E-TEC .
Then of course a new tachometer, P/N: 10k SYS CH

Total Cost = Priceless

Maybe I should just put a speedometer on the boat from e-bay and glue the needle at 60, I would get the same result. Oh and I almost forgot, a nitous button on the wheel.

11’,13’, 21’ Revenge

shipskip posted 01-16-2008 03:13 PM ET (US)     Profile for shipskip  Send Email to shipskip     
quoting jimh, "I wonder how people knew when they reached 45-MPH back in the good old days? Running on a timed course?"

Exactly. In Seattle on Lake Washington, there is a measured nautical mile course on the north side of the Hwy 520 Evergreen Point floating bridge and also one on the south side of the I-90 Mercer Island floating bridge.

Before GPS days, I ran the Hwy 520 course in my 1985 classic 15' SS with 70HP PTT Johnny and 13 3/4 x 15 SS prop using a hand held stop watch. Protected flat water alongside the bridge. No wind. No current. Trimmed out. One 210# driver, 12v battery, VRO tank and 6 gallons of fuel. No other gear. Do not know WOT RPM.

The time is embedded in my brain. 100 seconds. 36 knots. 41 MPH.

2manyboats posted 01-16-2008 06:06 PM ET (US)     Profile for 2manyboats  Send Email to 2manyboats     
MBAC After a few months of running my little 2 cylinder 60 E-TEC on the Montauk, I too am tired of mid 30's for speed and 8 mpg. There is an aftermarket programmer on ebay for about $25 that claims to let you go up to 100hp per cylinder.
It my be easier than the new mold on your 13.

Just search " make it run like an old mercury" and you should find the programmer.

jimh posted 01-16-2008 08:38 PM ET (US)     Profile for jimh  Send Email to jimh     
I used to have an old 1976 50-HP Mercury. It was a great little motor--and still is; it is still running. But even after trying four different propellers, I never got more than about 33-MPH out of it on my SPORT 15. I cannot imagine that it would have cranked 45-MPH on a SPORT 13. The difference in weight is not that great, maybe 200-lbs, and many people think the SPORT 15 is actually a faster hull.

According to Crouch, if my boat did 33-MPH with a 50-HP Mercury, then a boat that weighs 200-lbs less would do about 35.7-MPH.

In order for a boat that weighs 200-lbs less than my SPORT 15 to reach 45-MPH with the same engine (50-HP), the hull factor would have to jump to 227 from the usual 180.

I don't really think the 13-foot hull is that different from the 15-foot hull, and, according to some, the 15-foot hull is actually faster. So it is hard to figure how you could get 45-MPH out of that 50-HP Mercury. According to Crouch, you'd need more like 80-HP to reach that speed.

And according to Crouch, with 40-HP you get 32-MPH.

fourdfish posted 01-16-2008 08:47 PM ET (US)     Profile for fourdfish  Send Email to fourdfish     
I agree, My dads Sport 15 with a 48hp Johnson did a little over 30mph.
MBAC posted 01-17-2008 03:55 AM ET (US)     Profile for MBAC  Send Email to MBAC     
I love this place... Good laughs and good information. In all seriousness I did order the Stiletto Triad II in the 11-3/4" x 17" and I will report the performance. Thanks Tom... BTW, I did post the 14"x19" I had on the motor for one run.

11',13',21' Revenge

BQUICK posted 01-17-2008 01:11 PM ET (US)     Profile for BQUICK  Send Email to BQUICK     
Slightly off topic--I don't know who Crouch is but maybe he is sitting on a couch....not out on the water. I have been running over 40 mph on a 13 ft for 36 years with a 50 Merc. The way to do it is running the tilt high or using power trim. Confirmed it with GPS this last year. (44 mph) with a tired 1974 motor. Speedo was showing 46 mph. It can and has been done.
jimh posted 01-17-2008 08:19 PM ET (US)     Profile for jimh  Send Email to jimh     
Crouch is a naval architect who provided a formula for predicting speed as a function of horsepower. Read more at

If you have developed a better description of the relationship between boat speed and horsepower, please feel free to enlighten us. We are always looking to expand the collective knowledge of recreational boaters.

Tohsgib posted 01-18-2008 10:50 AM ET (US)     Profile for Tohsgib  Send Email to Tohsgib     
It can be done in a 5mph current.
makoman310 posted 01-18-2008 06:05 PM ET (US)     Profile for makoman310  Send Email to makoman310     
[I] have a [1972 Boston Whaler SOURPUSS 13] with a 1965 40 10 12 propeller and she tops out at 38-MPH. [The 1972 Boston Whaler SOURPUSS 13 is] still fast after all these years.
ncy7d posted 01-20-2008 09:09 AM ET (US)     Profile for ncy7d  Send Email to ncy7d     
I hit 34-MPH in my 13 footer with a 40-HP Tohatsu with two adults on board and 6 gallons of gas.
Sal DiMercurio posted 01-20-2008 10:27 AM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
I don't understand where some of you guys think there is a maximum speed for any planing hull.
Do you guys really think a 13' boston whaler will only do 45 mph no matter how much hp is hanging on the transom? I guaranty you, that I or anyone else, can get more speed out of that boat, so called maximum speed with an engine with more hp and the right pitched prop. You are only going to go so fast with a 40 hp engine, but put an engine with 70 or 90 hp on it and watch that boat fly. Had some guy try and tell me a Montauk will only do 45 mph no matter how much hp it had on it's transom. I bet him $1,000 I could get more top end speed with a higher hp engine hanging on its transom, with a higher pitched prop. He wouldn't go for it. Sal
Tohsgib posted 01-20-2008 11:39 AM ET (US)     Profile for Tohsgib  Send Email to Tohsgib     
No Sal, we are not saying that. What we are saying is this, and this is a FACT:

A 13 with 40hp is SLOWER than a 15 with a 40hp even though it weighs a couple hundred pounds less. Reason is hull design. A 15 with a 50hp will MAYBE do 40 if set up right, so why do some think their powerhead rated 50hp on a 13' will do 45+. It takes a 70hp on a 15 to do 45+ so why would a 50hp go faster on a 13'? The same goes for an 11 vs a 13'. Put a 25 on an 11 and the 13 w/25 will be faster. So don't think a 50 on an 11 would get you like 50mph.

Yes there is limitations to a Whaler Cathedral hull and it is again due to hull design and efficiency. A 13 will plane with a 10hp because it is efficient. This efficiency has an adverse effect after certain MPH. What we mean to say is a 25hp will fetch you 30mph. A 50hp will fetch you about 40mph so a 100% increase in Hp gave you 10mph or 33% more speed. So a 100hp would theoretically give you like could but then again the boat would probably flip. A 100hp on a 15 is obtainable and will handle it pretty well.

Guy down here had a montauk with a 200hp Yamaha, he said it barely did 60. Which is about 10mph more than I would feel comfortable in a montauk. It is also only 10mph faster than what it would do with 1/2 the hp.

Then you race guys will pitch in and you have valid points that if you strapped a 2.5EFI on it you could get 70+ and you probably could but that is breaking the rules because now the boat is not even touching the water. You can get anything to go crazy fast but that most likely would lead to a disaster and hence why nobody would slap a $20k engine on it to try...or would they?

Sal DiMercurio posted 01-20-2008 12:13 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
Thanks Nick.
In a couple posts, "it seemed" like guys were saying, no matter what hp engine, or pitch prop on a 13, it will only get X miles per hour. I agree that anything over 40 - 45 mph on a 13' is gonna get a little wild.
PeteB88 posted 01-20-2008 12:17 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
I have not been faster than just over 30 with my 13-foot Boston Whaler boat and Yamaha 40-HP. Only checked it once with hand held GPSr and plan to do more when I put new electronics on her this spring. 30 is fast enough for that boat I think and I am not afraid. However, I did Jimh's calculator at like 800 pound assuming load, driver some gear and it came out like 44 mph and much faster just factoring published hull and motor weight.
jimh posted 01-20-2008 06:31 PM ET (US)     Profile for jimh  Send Email to jimh     
Is there anyone who can confirm that they get an "easy 45-MPH" out of their 13-foot Boston Whaler with any motor of any horsepower?
BQUICK posted 01-22-2008 11:47 AM ET (US)     Profile for BQUICK  Send Email to BQUICK     
Jim, I don't know what you mean by "easy" but like I said it has been done and not just by a few.....
You can't go out there with the tilt down and plow along. The tilt has to be out to get the hull that was not designed for speed OUT of the water. Before power trim we used to put a trailer roller on the tilt pin to get more trim.
My current motor does not have power trim but when I had it on there you could open it up with normal trim and start pushing the up button and gain 8-10 mph.

With a modern jack plate setup I'm sure more could be attained. Prop selection is also important and with a speed prop of 17 or 19 in pitch it will be a dog with 2 or more people on board.
If you are in Rhode Island in the summer I'd gladly demonstrate.

Tohsgib posted 01-22-2008 02:20 PM ET (US)     Profile for Tohsgib  Send Email to Tohsgib     
1981 13 sport with wraparound rail, custom box under front twart the width of the boat(est 50lbs with gear inside). I full 6 gal tank and one group 24 battery, 4lb anchor and rhode. I have a 8" setback jackplate and am up about 4". I am running a 40hp Evinrude 1994 with over 140psi in both pots. I am running a 11.75x17 Polished SS Rapture prop. I do have bottom paint but it is smooth and not thick so I doubt it does much in hindering my performance. I can get about 5600rm full tilt boogie with just my 220lb arse in it. Does anyone want to see what the calculator does with that info? I do not know the gear ration but I could find out if nobody else knows. I raced Reely-Mine on a freshwater river(slower than salt) on glass conditions. His smartcraft said we hit like 37.3 and we were neck and neck. I also had a loaded cooler durng that run so add another 40lbs.
Tohsgib posted 01-22-2008 02:20 PM ET (US)     Profile for Tohsgib  Send Email to Tohsgib     
PS...yes it is PTnT.
jimh posted 01-23-2008 01:17 AM ET (US)     Profile for jimh  Send Email to jimh     
Nick--Thanks for the data. I put it into Crouch's Calculator to deduce the hull weight assuming a HULL FACTOR of 180. Then I bump up the horsepower to 50-HP and predict the speed using the same weight and hull factor: I only get 41.7-MPH. I don't know where the extra 3.3-MPH are. Maybe more horsepower. Next I recompute assuming 45-MPH and solve for horsepower needed: 58-HP. I guess if you have a 60-HP engine on a nicely set up 13-foot you should hit 45-MPH "with ease."
Tohsgib posted 01-23-2008 10:25 AM ET (US)     Profile for Tohsgib  Send Email to Tohsgib     
What about 25hp?
Spooky posted 01-26-2008 03:35 PM ET (US)     Profile for Spooky  Send Email to Spooky     

Regarding your mention of the speed limiting "lip", assuming that the "fix" is for real... - does the 13' fix make the hull essentially flush flat at the transom rather than, what I have my current project 13', the curve downward which would seem to be taking away speed.

As I am in a complete transom rebuild and am adding a small hull extension to give some more buoyancy for the heavy four stroke (and storage), I had been thinking of taking out the "lip".

Would really appreciate a picture of the new hull shape without the lip.


jimh posted 01-26-2008 06:09 PM ET (US)     Profile for jimh  Send Email to jimh     
Steve--Instead of "lip" we usually refer to a hull having a bit of hook or rocker at the transom. Search on those terms to find prior discussion.
Binkie posted 01-26-2008 10:23 PM ET (US)     Profile for Binkie  Send Email to Binkie     
Lay a straightedge about 5 foot long on the bottom of an overturned 13 footer, and you will see an actual hook, along with the lip at the stern. I would say the boat was designed for the motors in use in the mid-late `50`s, mostly 25-40shaft hp, weighing about 135lbs. or less, and will plane with 20hp. My `61 13 footer will do 28mph gps, with its 50 year old 35hp Evinrude, of course no pt-t. The boat will jump up on plane run flat and does not porpoise. It will also run over the top of a 1 ft. chop pretty smoothly, wide open. It is a completely different and more comfortable ride that my daughters `76 13 footer with an `03 40hp Merc. 2 stroke, which is fairly wild in a small chop at wide open speeds. There is no limitations on the speed of any planing hull, and the more hp you put on, the more speed it will obtain, but on the 13 ` Whaler the speed is given up grudgingly and with lots of complaints due to the bottom design. If you want to go faster get a 15 footer.

Also I think my boat rides better due to the interior being moved forward 6". Has anyone noticed the 50th anniversary 13 foot Whaler seems to have the console moved forward a bit.


Spooky posted 01-27-2008 12:30 AM ET (US)     Profile for Spooky  Send Email to Spooky     
Binkie - what is the difference between your 60's and 70's versions of the 13"? Does the 60's version not have the hook?

I am in the middle of a complete rebuild so flattening out the hull is no big deal in relation to everything else with the that light, is the "fix" to simply plane off the hook?


BQUICK posted 01-28-2008 10:07 AM ET (US)     Profile for BQUICK  Send Email to BQUICK     
My 71 Sourpus has more hook than my 68 hull. Was slower (w/50 Merc) than the 68 until I put power trim on.

Best setup would probably be no hook and power trim.
Without power trim the tilt would have to be in in order to control porpoising. Or for just top speed only one could drive through the porpoising toward top speed ala race boat style.

Tohsgib posted 01-28-2008 11:37 AM ET (US)     Profile for Tohsgib  Send Email to Tohsgib     
The newer 78+ hulls are different as well. The older ones had those little strake thingies on the bottom as well which the newer ones do not. My 76 hull was more like my 64. My 79 & 81 are totally different than both.

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