Penny HMD19

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TomW1
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Re: Penny HMD19

Post by TomW1 »

Okay, I think I know the problem. You have the XL shaft and that is putting the prop way too deep below where it should be. Your motors ventilation plate should be even with the bottom of the hull. If you are getting ventilation a different prop can fix that.

Lugging an engine is when it cannot run at its proper operating range and the results are carbon build up, ring damage, valve seal damage, etc. I would not worry about it to much as I looked up your motor and it lists the operating range from 5000- 6000, but it would be best if you could get that a little higher.

You know let's get simple here and not worry about anything else I said in the 1st Para, just get a new prop of the same type 1 pitch down, in other words a 6 pitch that will increase your rpm's 2-300 rpm's put you in the middle of the range and not have to worry about anything else. Deal!!!!! You should not notice any performance changes.

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

blueflood
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Re: Penny HMD19

Post by blueflood »

Thanks a million Tom :D

Ok phew it does not sound that bad. The transom cut out was raised about 4" at the build (plans showed deeper) so the engine would not sit TOO low but sounds like it is still too low :help:

Perhaps I should have bought the long shaft vs the xlong but as you say I'm still in the operating range at 5200+ rpm.

I will shop around for Christmas ! I told my wife after explaining the issue that we may need a different prop to avoid engine damage and she said no problem :D

Other HMD19 pilots...any figures and similar issue ?

Edit, i shopped around and what is only available is a 10" X 5" pitch four bladed. Would this be ok ?
Over reving potential maybe ?

Marc
Last edited by blueflood on Tue Sep 13, 2022 11:39 am, edited 1 time in total.

Cowbro
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Re: Penny HMD19

Post by Cowbro »

WOT?????

I have never gone WOT in my HMD. The boat is not designed to cruise over 5knots. I am usually right around 2700-3000rpms. The depth of the motor might cause a little extra drag, but it shouldn't be a hinderance in performance for these boats other than the powerhead being a little close to the water. I don't think it would be proper to select a prop for these boats that allows max RPM.

When i replaced my Tohatsu 9.8 with a Suzuki 9.9 EFI the motor came with a 10x5 prop, but i was spinning over 3500rpms at ~4.5 knots, I changed to a 10x7 and it dropped the rpms to under 3000 at optimum cruise.

Phil

blueflood
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Re: Penny HMD19

Post by blueflood »

Hi Phil,

WOT is prescribed in the break-in procedures. After two hours or so of intial various slow speeds
they say to power up for no more than 5 minutes every so often (cant recall but say every 10 minutes) for the next so many hours (8?) after that.

The break-in should be good then. I usually cruise at 4000-4200, she rides sweet and best, generates less noise and is so-so on fuel burn. The engine really sucks gas at WOT bc of her hull. Other than that I power down when really not in a hurry.

I need to see what the engine and boat can do in chop and wind. Last windy and wavy outing was not a problem and was the worst condition we took her out in. Good to see the extra power she has.

That said the XL long shaft debate goes on 😁
The drawings should show suggested transom cutout dimensions for different shaft lengths 👍🏻

When I designed to interior and outfitting, the outboard is shown with location. I got the outline and dimensions from Mercury. First to keep it low in water, for noise control hiding behind the frame and also limited space to run the cables in motor well. Dwg is also shown with a higher transom cutout. The ventilation plate is way low...

Image
Marc

TomW1
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Re: Penny HMD19

Post by TomW1 »

blueflood wrote: Tue Sep 13, 2022 7:33 am Thanks a million Tom :D

Ok phew it does not sound that bad. The transom cut out was raised about 4" at the build (plans showed deeper) so the engine would not sit TOO low but sounds like it is still too low :help:

Perhaps I should have bought the long shaft vs the xlong but as you say I'm still in the operating range at 5200+ rpm.

I will shop around for Christmas ! I told my wife after explaining the issue that we may need a different prop to avoid engine damage and she said no problem :D

Other HMD19 pilots...any figures and similar issue ?

Edit, i shopped around and what is only available is a 10" X 5" pitch four bladed. Would this be ok ?
Over reving potential maybe ?

Marc
Yes, not at all that will put you at about 5600-5700 rpm's still well under the max 6000 rpm's for your motor. Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

Fuzz
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Re: Penny HMD19

Post by Fuzz »

Nice thing about that XL shaft is it lets you mount the motor as high as possible keeping the power head out of the water better. At 5-7 knots I am not sure being mounted low is really hurting you all that much. If this was a planing hull that would be a different story. My 22 foot SeaSport has a 9.9 Suzuki on it. No tack but around half throttle it pushes the boat 5 knots. Wide open just makes more noise and burns more gas.

TomW1
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Re: Penny HMD19

Post by TomW1 »

Fuzz wrote: Wed Sep 14, 2022 11:54 pm Nice thing about that XL shaft is it lets you mount the motor as high as possible keeping the power head out of the water better. At 5-7 knots I am not sure being mounted low is really hurting you all that much. If this was a planing hull that would be a different story. My 22 foot SeaSport has a 9.9 Suzuki on it. No tack but around half throttle it pushes the boat 5 knots. Wide open just makes more noise and burns more gas.
Fuzz that is interesting on your SeaSport do you use the 9.9 as a trolling motor? I am not trying to do much with his setup or prop, just get it a little higher into the rpm range at top rpm's. He will never use it much there, but it will prolong the motors life. Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

Fuzz
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Re: Penny HMD19

Post by Fuzz »

Yes Tom. I use the 9.9 for trolling. I need to be running 1.8-2.2 knots for salmon. A lot of the time I will run the trolling motor to save the hours on the main motor. My Suzuki 200 will ideal at 2.0 so I use it some times also.

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Re: Penny HMD19

Post by Bogieman »

This is such a nice build thread. I admire your craftsmanship as well. I've had HMD19 plans for a while. I didn't think I'd build another boat after building "Tipsy" my AD16, but looking at your thread is getting me itching again. :D

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Re: Penny HMD19

Post by Jaysen »

Bogieman wrote: Mon Jan 09, 2023 3:04 pm This is such a nice build thread. I admire your craftsmanship as well. I've had HMD19 plans for a while. I didn't think I'd build another boat after building "Tipsy" my AD16, but looking at your thread is getting me itching again. :D
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