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Conference vicki::boats

Title:Powerboats
Notice:Introductions 2 /Classifieds 3 / '97 Ski Season 1267
Moderator:KWLITY::SUTER
Created:Thu May 12 1988
Last Modified:Wed Jun 04 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1275
Total number of notes:18109

1034.0. "Advice on correct engine power" by MEOC02::BOUNDS () Tue Jan 05 1993 22:51

I've just inhereted a 12' Aluminimum dinghy with a 6 HP johnson outboard. I've no 
background in boats and engines but after trialing the boat I know that I need 
a bigger motor as with 2 people and gear it will not plane. From reading 
through this conference and my other enquires, 15 or 20 HP seem to be my choices.
I have no idea of the boats power rating but have used a similar 20HP combination
some years ago and it flew. However if I put down the circumstances under which
the boat will be used some advice from the more experienced may help me decide.

I have no boat trailer but a car rack and the boat will be launched off the 
beach or at a ramp. It will be used in an area where 8 kt rips and ocean 
conditions maybe encountered (at the narrow heads of a large bay). The trip to
this area is about 15 mins by 60 HP boat or 40 mins with the 6HP and I need to do
it at short notice and quickly when the conditions are right.

Price is not a consideration it is the right power, boat balance and engine 
manageability I'm after. For example the 20HP will weight about 115 Lb opposed
to the 15 HP at about 72 lb.

	Thanks Alan.

 
T.RTitleUserPersonal
Name
DateLines
1034.1Don't do it!GOLF::WILSONI'm bailing as fast as I canWed Jan 06 1993 09:4019
I only have a couple minutes here, will add more later unless someone
beats me to it.

For the conditions in which you plan to operate, and equipment you plan
yo use, you're flirting with MAJOR disaster!  First off, most 12' "dinghies"
are rated for no more than 10hp.  For some it's as little as 7.5hp.
Secondly, a 12' dinghy, powered by a 20 hp motor, with 2 men and fishing 
gear on board, has NO PLACE whatsoever in the "8 kt rips and ocean conditions"
you plan to use it in.

If you don't believe me, pick up a copy of Offshore magazine.  Every month
you can read about guys who did the same thing in the Coast Guard Log section
in the back of the magazine.  Usually one will be found clinging to the boat,
and the other is missing.

Do yourself a favor.  Either stick to protected waters, or get yourself a
bigger boat.

Rick
1034.2Take Rick's advice - don't do itTUNER::CHACEMy favorite season is getting nearer!Wed Jan 06 1993 13:0825
    
     I agree, Rick is precisely right and I would have said the same
    things, but he beat me to it.
    
      Regardless of all else, I doubt you should put more than a 10Hp
    motor on a 12' aluminum boat. 
    
      Any type of rough conditions that you may encounter with that boat
    can easily swamp it. It is *possible* (but I sure wouldn't recommend)
    to pick PERFECT weather days and go back in at the FIRST sign of the
    seas getting bad. But actually going out IN bad seas and a heavy
    current in a boat that size is REALLY flirting with disaster. One of
    the main differences you will find in a boat designed for ocean use, is
    a LARGE increase in freeboard. This is to allow an extra margin of
    safety when (yes when, not if) encountering larger waves which can
    happen unexpectedly, even on a good day. With two guys and gear and a
    10 hp motor, the boat will in all likelihood be maxed out with the load
    it can safely carry if not slightly over. You'll have *maybe* one foot
    of freeboard in a boat that is rather tippy under the best conditions.
    Even the passing of a fairly small sport-fisherman can produce waves
    much larger than that.
    
    				Don't do it.
    
    				Kenny
1034.3Car topper in those waters??.... Not me...SUBPAC::CRONINWed Jan 06 1993 13:1910
    	There are a few (VERY few) 12 ft. alu. boats rated for 20hp.  These
    are not the type of boats you'd want to try lifting onto your cars roof.
    They are deep, wide and heavy.  I have used a friends light 12 ft.
    w/15hp a few times and it was too much motor for the boat.  In fact
    he's used it for about 5 years now and the boat is literally falling
    apart.  I think it leaks at EVERY rivit in the stern of the boat.
    	I have a 15ft. Whaler w/70hp and I feel that it's too small for the
    conditions that you describe.  If I'm going to err I want it to be on
    the side of safety, not risk.
    					B.C.
1034.4It's not as bad as it seemsMEOC02::BOUNDSWed Jan 06 1993 17:3912
Actually the conditions when I go in there are not as bad as my note gives the 
impression of. The trip is in sheltered conditions close to a shore line with 
offshore winds (very flat surface conditions) and the anchorage is close to shore
sheltered, with some swell movement and the 8kt tidal current. I also have 
marine radio and as the spot is popular there are always a few boats in there. 
I have never gone in, in rough onshore conditions which as you say is asking for
trouble, particularly in a small boat.

Anyway I appreciate the comments and they make me tend towards a 15HP and as a 
second step a larger boat/motor/trailer combination.  

	Alan. 
1034.5Be conservative and live longerSTAR::KENNEYWed Jan 06 1993 18:1618
    	Look at the boat real close there should be a rating plate on
    back of the boat.  The rating plate will spell out the maximum sized
    motor and number of passengers.  In the U.S. it is the law all boats
    built in the last 20+ years have to have them.  I am not sure about
    other parts of the world but they make good sense.  I would be real
    surprised to find that it is rated for more than 10hp.  


    	I used to work for the ship hydrodynamic laboratory at the
    University of Michigan.  We did a some work for lawyers looking at
    several small boat  accidents.  Most fatal accidents resulted  from
    owners over loading boats and then using them in conditions they were
    not designed for.  Depending upon which side the lawyer was on they
    either loved our work or were real slow paying for it.  Do yourself a
    favor get a boat appropriate for the task.

    Forrest
1034.6Sounds scary to meTUNER::CHACEMy favorite season is getting nearer!Thu Jan 07 1993 09:5016
    Alan - You state in your opening note that you have no background in
    boats. What you think of as not bad conditions may be not bad for a
    larger boat but very bad for a 12' rowboat. (Yes, that's what it really
    is) A 20 minute ride through a sheltered area can turn into an hour if
    the wind whips up a bit and who can say what else can happen to tyhe
    weather in that hour?
    
    	I would like to HIGHLY recommend that you take a boating safety
    course. The information you get there is wonderful. It's time well
    spent. There are course starting up at this time of year in many
    places. A call to the local Power Squadron will get you the info as to
    where.
    
      Question: Exactly where is this place where you plan to be going?
    
    				Kenny
1034.7Take it from one who's lucky to be hereGOLF::WILSONI'm bailing as fast as I canThu Jan 07 1993 10:1237
    re: .6
    Good advice, a safety course for novices is ALWAYS agood idea. I
    waited about 2 seasons before taking the course myself. Afterward,
    I realized some of the crazy things I had done, and how lucky I 
    was on a couple of occasions.  One thing the course will do for 
    you, is give you healthy respect for the ocean if you didn't
    have it already. The segment on hypothermia is very enlightening.
    I think the course may change Alan's mind on the wisdom of taking
    a fully loaded undersized and overpowered boat out in saltwater,
    where the potential for rough conditions *always* exists.
    
    Another interesting point, is an article in this month's issue of
    BOAT/US Reports.  It said that over 60% of boating fatalities 
    occur in boats under 16', and that most victims do not consider
    themselves to be primarily "boaters".  That means that they were
    on the boat for another purpose, such as fishing or hunting.
    Activities that require a fair amount of moving around in the
    boat, the participants don't have much if any boating experience,
    and are paying attention mostly to their hunting or fishing.
    Sound familiar?
    
    Don't take it personally Alan.  Those of us telling you not to
    do it are saying it because we care enough to try and prevent 
    you from hurting yourself.  Your intended use has ALL the classic 
    signs of the typical boating accident waiting to happen.
    
    One other thing - there's no "law" against putting a 15hp motor 
    on a boat rated for 10hp.  But if an accident occurs and your
    partner gets hurt or killed and you survive, and it can be proven
    that you knowingly used a boat that was inappropriate for the 
    conditions, you'll be working to pay off the lawsuit for the rest 
    of your life.  Since you said the money for a bigger outboard is
    not a problem, sell the boat and motor for the $6-800 they're
    probably worth, and combine that with your outboard money to buy 
    a bigger, safer boat.
    
    Rick
1034.8worth every $0.01CAPL::LANDRY_DThu Jan 07 1993 15:1126
	I agree with the recommendation to take a safe boating class before
	going out in your own boat in fresh or Salt H2O.

	Not sure where you are but the Coast Guard will most likely be at
	the Worcester Boat Show starting today 7th and going till Sunday 10th.

	They usually have a booth set up with information on all the
	boat safety, navigation and other courses you can sign up for nearest
	where you live.  The only charge is for books and materials.

	I took the 13wk Boat Safety and Navigation course and between the two
	have needed that training a number of times on both Fresh and Salt H2O
	situations.  Prevented me from getting into dangerous situations and
	also got me out of the unexpected when I was faced with it.

	I am also a novice as this past year was my first full year of even
	owning a boat.  I've been a "passenger" for ouch number of yr's.

	Believe me after you attend one of these you can tell who knows
	what there doing out there and who doesn't so you can avoid getting
	too close to "an accident waiting to happen" or you can be there to
	help because your set up to do so. 

	Wishing you fun with Safety
	-< Tuna Tail >-
1034.9And I didn't even have to ask.AD::GAETZThu Jan 07 1993 15:116
    Even though I didn't ask the question, thanks for the info.
    I was thinking of getting a sm used outboard for my father who also
    has a 12 ft V-hull Aluminum boat. I was thinking a 7hp would
    be alright. He would use it in local small lakes.
    
    Mg
1034.10Lets not forget the ENET spans the worldSTAR::KENNEYThu Jan 07 1993 15:267
    
    	The person who entered this is located in Melbourne Australia. 
    That is why in .5 I indicated that U.S. builders are required to place
    a rating plate on the hull.  What they have to do in other parts of the
    world I have no idea.  I agree a boating education course never hurts.
    
    Forrest
1034.11The Heads, Port Phillip Bay , Victoria AustraliaMEOC02::BOUNDSThu Jan 07 1993 17:3913
The Heads are actually called the rip and are about 1.5K wide opening into Port
Phillip Bay. The channel is even narrower 750 m. An interesting area full of ship
wrecks, good fishing and diving. Our Prime Minister disappeared while going for a
swim just around the corner on the ocena side in the 70's, never seen again.

Our boats down here do have power ratings and I am trying to find out what 
mine is from the agent before I do anything. We also have a marine rescue service 
that runs power boat courses. The course has been recommended to me by a friend
but the discussion here has made me decide to definitely do it. 

	Thanks for the input

		Alan.    
1034.12I really enjoyed itTUNER::CHACEMy favorite season is getting nearer!Fri Jan 08 1993 08:4312
    
    Alan - It's great to hear that you'll be taking a course. Of course I
    can't say for what the courses there are like, but if they're anything
    like here. They're not too much work and if you're interested in
    boating to begin with, they are actually quite fun. I'm very seriously
    considering taking the more advanced courses, even though I likely
    wouldn't use the more specialized information. It's just that, I got so
    much more than I expected out of my first one and things I never would
    have thought of. And that was after spending 20 full years on the ocean
    in all sorts of boats.
    
    					Kenny
1034.13Hi from Way Up Over....CAPL::LANDRY_DFri Jan 08 1993 12:1526
Alan,
	Nice to hear from Way Down Under.
	Don't know where that experssion began or why?

	Anyway...I've done a lot of Military, DEC and personal travel:
		 US 48 states (need to do North Dakota & Alaska)
		 Canada, Mexico, Puerto Rico, Bahama's, Bermuda
		 Europe: most of the countries
		 Far East: Okinawa, Japan, Hong Kong, China (snuck in pre Nixon)
			   S Vietnam, N. Vietnam (does flying over count?)
			   Thailand

	I've alway's wanted to go to Australia and do some "serious" fishing.
	(I chose Hong Kong for R&R while in Nam over Australia & Hawaii)

	If ever things settle down with us here in DEC I'm planning on taking
	my wife around the world...in a plane :^) and would obviously target
	Australia as #1 priority.  (With all this travel I have never crossed
	the Equator)

	When ever this occurs can I ask for some help from you as to where
	the best fishing is?  Naturally we hear The Great Barrier Reef but
	I'd rather here direct from those who may know.

	thanks
	-< Tuna Tail >-
1034.14MEOC02::BOUNDSSun Jan 10 1993 18:5522
The manufacturer of the boat went out of business 10 years ago, so I guess that 
mine could be up to 15 years old. I found the almost unreadable specification
plate and managed to make out a recommended 6 H.P. on it. I'm going to take it in 
to the local marine shop and get them to survey it. On that outcome I'll either 
keep it or get something else perhaps more appropriate for my use. As it was 
explained to me, aluminimum boats of that age with rivets have a tendancy to 
crack around the rivet particularly when flexing under load. The newer boats
of a similar design are all (out here) rated for 15 H.P.

re .13 I prefer holidays to more isolated non tourist spots. In 1990 I spent 
a month in NW Australia between Canarvan and Exmouth. Similar semi desert 
country to Baja Mexcio I imagine. There is a coral reef (the most southerly in
the world) called Ningaloo Reef that runs 100m to 2Km offshore. It is every bit 
as good as the Great Barrier reef but is virtually untouched. You need 4WD (for
boats launched off the beaches especially) drinking water (bore water showers)
and camping gear. I've never seen fishing like it if you have a boat (yellow tail
Kingfish, Red Emperor, Snapper). In fact there was until recently a US navel
communications facility at Exmouth. I reckon that would have to be the best 
overseas posting you could ever have.    


	Alan.
1034.15A different approachJULIET::ERICKSON_BLFri Jan 15 1993 19:339
    Another way may be to use a 14 or 15 foot inflatable such as an Avon or
    Achillis. These boats are designed to be used in rough water and are
    very light. In addition to this you can use a 25 to 35 hp outboard. I
    currently use mine for diving, fishing or just blasting around. I have
    not had any problem with fishhooks puncturing or any problem for that
    matter.
    
    Inflatables can be carried on the rooftop or even taken down. After a
    few tries it takes about 45min to assemble.
1034.16Infatable SupportNZOMIS::DUKESun Jan 17 1993 14:417
    I would support the use of an inflatable as .15 suggests. I use one
    often in company with friends tinnie and the inflatable wins hands
    down.
    
    It more stable, comfortable and handles a bigger load. The one I use is
    a Zodiac SERIE1 134, 3.4m with a 15. It has an inflatable keel (a must) and
    runs really well with either a 8hp or 15.  
1034.17Bigger ain't better!GLDOA::DBOSAKWed Apr 14 1993 12:3513
    I use an Achilles 10 foot as the Scurvy Queen's dingy -- I'm running a
    10 HP motor on it and the thing flies -- I'd be real goosy about using
    a small boat for anything other than for dingy stuff.  
    
    On the Great Lakes, we say that big water is for big boats -- If U
    insist on boating in the little thing, ensure that you have a compass
    and flares.  Anything that can happen will!
    
    It sounds to me that U plan to use this as waterborne recreational
    transportation -- You don't need a rocket to do that -- My guess is
    that a 5-7 HP engine is Max.
    
    Cap'n Ahab