MacGregorSailors.com

His concern is for safety of the people if the equipment is handled wrong or excessive weight. I pointed out that variations of a few hundred pounds are well within the normal range of variation. Just inviting someone to go boating can bring in 250 pounds.

A discussion centering on differences in motor weight might be a right answer, but it's the wrong question. As you point out, the difference in weight is not that significant. What is significant but not mentioned is that the loads on the entire boat generated by a 90HP motor at WOT compared to a 50HP motor at WOT are 90/50, or 1.8X. 140/50=2.8X. And so on.

In fact, a frequent contributor to this board hit an underwater obstacle at high speed with the lower unit on his upsized motor. I believe it was the first time he had it out. Instead of the motor kicking up without damage like a 50HP probably would have, the 120 (might have been 140, I don't remember which) nearly ripped his reinforced transom right out of the boat. The boat suffered extensive damage; insurance and or the installing dealer paid for it, but as I recall his brand new boat was out of commission for an entire season for repairs, which as I also recall ran to the high thousands $$. No mention of what happened to his insurance rates. I dont recall the name offhand; if you search the archive you'll find the whole story.

I'm not trying to discourage you from installing a larger motor. Many have done so with success, and if I'd had the $$ I would have done so myself a few years ago. Just be aware of all the implications.

Catigale, you're overdramatizing this relevant question. The parameters are safety and responsible operation.

The question is what is the purpose-specific practical horsepower for this boat as seen by people who actually have achieved the advertised performance in practical usage?

So, if you put necessary stuff in your boat and get 22mph, what horsepower motor is doing that for you?

As long as your on this subject can you tell me how to have the rudders, DB and ballast set when trying to use the power of a 50HP or more motor.
Even in smooth seas my "M" seems to get very squirrely and is hard to steer in a straight line over 10 knots. I don't feel comfortable unless I power back to about 3800 rpm (9 knots).
I'm trying 1 rudder down and the DB lowered about 12" and the ballest full but it still loose.

Thanks

Billfish:

The DB (CB on X) and rudders should be raised completely when motoring above 7mph. Ballast is irrelevant.

That you didn't know this indicates you have not read the owners' manual. Please do so before you leave the dock again.

ChrisP:

Catigale is not overdramitizing, his point is on the money. The advertized speed is 22mph, boat and ballast empty, with a 50HP motor. It's not 22mph under any HP or loading condition as you seem to be insisting, because any other loading condition imposes substantial additional loads on the boat and its systems. Anything past this is stretching the envelope. Can the boat take it? Others' experience would say probably so, but it's not to be undertaken casually, and (as Bill no doubt told you) done at your own and your boat's risk.

I'm a Mechanical Engineer by trade and one of the things I do for a living is find out how hard it is to break stuff.

Billfish: It seems most all of us acknowledge that the rules are. . .
#1.Sails up, all boards down full ballast.
#2.Motor running at more than docking speeds all boards up!
#3.while motoring you have two choices with ballast all in / full to the brim or all out!
#4. At No time are you to ever be running with a partial ballast.
Well except while filling or emptying ...

we should all agree that there that there is no wreckless disregard for safety in this scenario.

Agreed.

You can kill yourself/someone else just as easily with a 50HP as with a larger motor if you are reckless.

I do believe most everyone who has upped the HP has also reinforced the transom - if this done poorly your transom will crack though - search Mark Prouty's posts in the Main Board (this one) for the story there from a few years back.

If you want the 22 mph with a couple people up I think you will have to go the 90 HP of your choice.

Ah yes. Thanks, Cat. Mark Prouty was the name I couldn't think of.

I searched and it appears Mark's last post was in Sep '06. As I recall he sold his Mac and abandoned the board.

Chip Hindes wrote:Ah yes. Thanks, Cat. Mark Prouty was the name I couldn't think of.

I searched and it appears Mark's last post was in Sep '06. As I recall he sold his Mac and abandoned the board.

Yes Mark stated that he and his lads would be moving on to yet other adventures!

Guys, I'm not re-inventing things. I don't want to disregard safey, change realities, push the envelope or blaze new trails. There are people on this board who have actual experience with larger motors, meaning 90hp and up. And I want to learn from them.

So, to anyone who has a 90hp or above, what kind of powered performance are you getting? Are you able to safely cruise 2 with 3-4 days of supplies and safety equipment and reliably get 22mph or better in ideal conditions?

I'm happy at six to eight knots and all the reserve power I need if I get in a tight spot. Honda 50 w/stock prop. Got 18 knots first day out with light loading in ideal conditions. I'm more impressed with the fact that I have a more than modest cruiser that doesn't cost me a hundred bucks in gas everytime I pull away from the pier!

Hey Chris,

While I may be one of those "glass is half empty" pestimisses
My answer to similar inquiries are found here

My motor has been checked by almost every Evinrude on the NE seaboard. They say it's fine. I need to lighten her up next season and see what I get.

Mind you I have in the bow: Two anchors with a total of 18 ft of 5/8 chain, approx 30 gal of water from a plastimo under the vee berth, one series 27 Batt, had 2; and I've always run with a full cooler and stocked galley. And lots of junk in the rear berth. You'd think I was sailing to England

There's gonna be some serious changes next season where I'm dumping all the SHtuff I don't use - and it's alot. This wastes allot of gas & Kts.

There are people on this board who have actual experience with larger motors, meaning 90hp and up. And I want to learn from them.

Sorry "ChrisP and Pam".... I don't have a 90.... but the info found in this link might be of use to you....

http://macgregorsailors.com/phpBB/viewt ... ly+mounted

I find heavily loaded I like 20mph at 3700 rpm for optimal fuel, noise, distance, handling, etc.

G

Interesting - Gaz' thread reports max of 17 kts with a 90 HP but he is not reaching his WOT rpm reading - ergo something is wrong.

Geoff reaches 20 mph (about 17 kts) with his 75 HP

You might want to consider you will only be doing 20 mph in this boat in 'near glass like' water conditions making the decision between the 75 and 90 (or more)

Hi Cat.... that was 20mph at 3700 rpm..... not WOT..... which is more like 28mph on glass like water at 1000 ASL.

As seen here....



G

Thanks Beene....without a doubt you are getting up on plane at that speed....I suspect part of Gaz' problem is he isnt doing that for some reason.