Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: 2014 90hp 4-stroke Yamaha too heavy for 1988 montauk 17

Posted by JRP on 05/19/17 - 7:57 AM
#18

Kdellaero wrote:
I think I've read enough to give me peace of mind with the transom issue, so I appreciate all the feedback. I'm just curious if it's normal to have to fight to keep the back edge of the boat from drifting under the edge of the dock at boat ramp. I was the only person in the boat and I weigh 155#. It felt like it had more to do with tilting that sitting low but it struck me as strange.


There are a lot of variables here, so it's hard to say whether this is normal or not. Is it a floating dock? Is it a fixed dock? What was the tide? Current? Wind?

Also factor that the classic Whaler designs have low freeboard and flat sheer, so will be less likely to match up well with a fixed dock if it is a tall one and/or the tide is out.


Finnegan wrote:
JRP - Someone at Whaler gave you the wrong information on the classic Outrage 18. Even in the eighties, almost all 150's weighed more than 400#, and Whaler often showed the boat with twin 70's, or a 150 single and a kicker. These combinations could weigh as much as 550#.

I have twin Merc 90's on mine (305# each), installed on 10" setback jackplates and a battery in each stern corner, and no problems, no stress cracks at all. Here is a photo with my son (150#) adding weight to the stern, plus a loaded Igloo cooler also:

http://smg.photobucket.com/user/lgolt...=6&o=8

Since your Outrage II weighs 600# more than the original, maybe on yours a 150HP 4-stroke at around #450# would be the max? Just don't know on that one.


Larry,

I absolutely love your Outrage 18 with the twin 90s, plus the optional anchor pulpit. What a beauty.

I did notice, though, that in one of the profile photos the boat is definitely trimmed down noticeably at the stern and up at the bow.

In general, a boat that is trimmed down at the stern will need to climb its way out of a deeper hole to jump up on plane. That will then require more power to achieve the same hole shot as a lighter less powerful engine. It's like a negative feedback loop: More weight causes more squat requiring more power which leads to more weight and so on...

There are some very interesting designs out there that demonstrate this effect, but going in the other direction. A good example is Willian Atkins' Rescue Minor skiff, which is about the same size as a Montauk 17. By keeping the static trim nearly flat and completely avoiding stern squat, Rescue Minor can hop up on plane with a full load with as little as 20 hp, and makes very little wake, too. (It does not attain comparable top speeds, though.)

These classic Whalers, with their relatively narrow beams, seem especially susceptible to stern squat with excess weight on the transom. I would love to have a <400 lbs engine option in the 135+ HP range. The closest to that right now is the Suzuki DF140A, at a little over 400 lbs.