Anonymous
01-22-2003, 10:06 PM
chris
normal member in standard member. 1. 20' diesel pilothouse
I recently bought a 1984 20' pilothouse. It has a 130 hp John Deere diesel in it. I havent gotten to use it too much so far, and i was looking for feedback from anyone else who has a diesel in this hull. So far, this is what I can say about the boat: wot(2400) is about 18kts, cruise(2100) is about 14 kts. This is with a beat up 13x13 three blade wheel. Also the boat came with a nice 14x16 three blade wheel that I intend to use on the boat. I am hoping to cruise at around 18 kts @2100. I dont know if i should try to get a wheel with more pitch or a cup to increase speed, but i have not tried the 14x16 yet so that may be premature. I know that with a diesel, you can spin a bigger wheel than with the same horsepower in gas, but with this hull there is no room to go bigger than 14". So far i like the boat a lot, and hope to put hours on it this year. Any feedback about this boat would be appreciated. Thanks, Chris.
Date: 07:19 p.m. on 03-28-2001
Leprechaun
premium member in standard member. 2. Re:20' diesel pilothouse
Chris - that prop sounds like its WAY oversquare for a 130 hp engine. I'm not sure the level of expertise your application requires is present on this board. (No offense implied or intended towards anyone). Why not surf over to www.boatdiesel.com and repost your situation and questions in their "General" area? Also - try to get ahold of Black Dog Props in Georgia (I think) and get their opinion. They have a website which URL escapes me at the moment. Rgds, Leprechaun
Date: 10:14 p.m. on 03-28-2001
green-o
normal member in standard member. 3. Re:20' diesel pilothouse
Go to www.miwheel.com. I think this is correct for michigan wheel. Put in all required info. like make of boat,size,model,weight,HP,etc. In 3 to 5 days they will give you the correct size prop.
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Keep it's head up. Tom G.
Date: 07:51 a.m. on 03-29-2001
Bill Thomas
normal member in standard member. 4. Re:20' diesel pilothouse
You need to know what WOT for that engine should be. I would guess you are close to where you should be now an another inch of diameter or pitch is all you can do without more HP. I think a 14x16 would need a more than 110-120 HP to move that boat at 20 knots. I have a 14" x 11" on my 22WAC with a 260HP engine and I think it is proped right. Your boat is lighter so I think you chould go 13x14 or 14x14.
Let us know how it goes - I may repower with diesel in a year or two.
Date: 10:56 a.m. on 03-29-2001
green-o
normal member in standard member. 5. Re:20' diesel pilothouse
Diesel engin's do not use the same gear as a gas engin. I have a 22wa with a 310 hp. It has a 1-1 gear in it. A diesel will probably have a 1-1.5 gear and a higher pitch prop. These are all the things you have to tell michigan wheel, and yes you have to know WOT rpm.
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Keep it's head up. Tom G.
Date: 07:39 p.m. on 03-29-2001
Leprechaun
premium member in standard member. 6. Re:20' diesel pilothouse
green-o - I don't think that a 20 has the bilge depth to have a 1.52:1 reduction box installed. Most likely that boat is a straight 1:1 drive w/o a reduction tail-housing. This of course will severely limit the size/pitch of the wheel Chris can swing. I looked at my old Shamrock literature and all the boats in each size, like the 20 pilot/predator/walk thru/and open had the same transmissions and unbelieveably, the same props. I mean tht diesels and the gas engined boats all swung identical props, as rigged from the factory. Wierd, ha? Rgds, Leprechaun
Date: 08:43 p.m. on 03-29-2001
Capt_Dog
premium member in standard member. 7. Re:20' diesel pilothouse
Chris,
First of all, as usual, the comments above are all heading you in the right direction. Be careful about rpm numbers versus speed with a diesel. Diesels can carry big props and run fairly good speed at low rpms. the only problem is that laboring a diesel engine with high load at low rpms is worse than running a gas engine at WOT all day long. The low rpms give you a false sense of security. Diesels will self destruct under extreme loads. Overheating will be your only clue. What Lep says about Shamrocks prop selection for deliveries of disimilar engines is scary.
Use the websites that offer prop sizing services. Do not be afraid to get several quotes, then decide. be sure to estimate your loaded weight, not the dry weight in the literature. A diesel 20' should provide the performance you mention with the correct props. The desing of these boats makes them not well suited for speeds much over 30 mph anyway. The new 200 Open with a diesel option literature states a 27 mph cruise with a range of 470 miles at that speed. that is with the 125hp Yanmar diesel and 90 gallons of fuel. That is over 6.5 mpg. That is incredible for a true inboard. Your pilot house and reduce hp will lower those targets for you, but you still have one hell of a package.
--------------------------------------------------------------------------------
Thanks, Lee
Date: 10:39 p.m. on 03-29-2001
normal member in standard member. 1. 20' diesel pilothouse
I recently bought a 1984 20' pilothouse. It has a 130 hp John Deere diesel in it. I havent gotten to use it too much so far, and i was looking for feedback from anyone else who has a diesel in this hull. So far, this is what I can say about the boat: wot(2400) is about 18kts, cruise(2100) is about 14 kts. This is with a beat up 13x13 three blade wheel. Also the boat came with a nice 14x16 three blade wheel that I intend to use on the boat. I am hoping to cruise at around 18 kts @2100. I dont know if i should try to get a wheel with more pitch or a cup to increase speed, but i have not tried the 14x16 yet so that may be premature. I know that with a diesel, you can spin a bigger wheel than with the same horsepower in gas, but with this hull there is no room to go bigger than 14". So far i like the boat a lot, and hope to put hours on it this year. Any feedback about this boat would be appreciated. Thanks, Chris.
Date: 07:19 p.m. on 03-28-2001
Leprechaun
premium member in standard member. 2. Re:20' diesel pilothouse
Chris - that prop sounds like its WAY oversquare for a 130 hp engine. I'm not sure the level of expertise your application requires is present on this board. (No offense implied or intended towards anyone). Why not surf over to www.boatdiesel.com and repost your situation and questions in their "General" area? Also - try to get ahold of Black Dog Props in Georgia (I think) and get their opinion. They have a website which URL escapes me at the moment. Rgds, Leprechaun
Date: 10:14 p.m. on 03-28-2001
green-o
normal member in standard member. 3. Re:20' diesel pilothouse
Go to www.miwheel.com. I think this is correct for michigan wheel. Put in all required info. like make of boat,size,model,weight,HP,etc. In 3 to 5 days they will give you the correct size prop.
--------------------------------------------------------------------------------
Keep it's head up. Tom G.
Date: 07:51 a.m. on 03-29-2001
Bill Thomas
normal member in standard member. 4. Re:20' diesel pilothouse
You need to know what WOT for that engine should be. I would guess you are close to where you should be now an another inch of diameter or pitch is all you can do without more HP. I think a 14x16 would need a more than 110-120 HP to move that boat at 20 knots. I have a 14" x 11" on my 22WAC with a 260HP engine and I think it is proped right. Your boat is lighter so I think you chould go 13x14 or 14x14.
Let us know how it goes - I may repower with diesel in a year or two.
Date: 10:56 a.m. on 03-29-2001
green-o
normal member in standard member. 5. Re:20' diesel pilothouse
Diesel engin's do not use the same gear as a gas engin. I have a 22wa with a 310 hp. It has a 1-1 gear in it. A diesel will probably have a 1-1.5 gear and a higher pitch prop. These are all the things you have to tell michigan wheel, and yes you have to know WOT rpm.
--------------------------------------------------------------------------------
Keep it's head up. Tom G.
Date: 07:39 p.m. on 03-29-2001
Leprechaun
premium member in standard member. 6. Re:20' diesel pilothouse
green-o - I don't think that a 20 has the bilge depth to have a 1.52:1 reduction box installed. Most likely that boat is a straight 1:1 drive w/o a reduction tail-housing. This of course will severely limit the size/pitch of the wheel Chris can swing. I looked at my old Shamrock literature and all the boats in each size, like the 20 pilot/predator/walk thru/and open had the same transmissions and unbelieveably, the same props. I mean tht diesels and the gas engined boats all swung identical props, as rigged from the factory. Wierd, ha? Rgds, Leprechaun
Date: 08:43 p.m. on 03-29-2001
Capt_Dog
premium member in standard member. 7. Re:20' diesel pilothouse
Chris,
First of all, as usual, the comments above are all heading you in the right direction. Be careful about rpm numbers versus speed with a diesel. Diesels can carry big props and run fairly good speed at low rpms. the only problem is that laboring a diesel engine with high load at low rpms is worse than running a gas engine at WOT all day long. The low rpms give you a false sense of security. Diesels will self destruct under extreme loads. Overheating will be your only clue. What Lep says about Shamrocks prop selection for deliveries of disimilar engines is scary.
Use the websites that offer prop sizing services. Do not be afraid to get several quotes, then decide. be sure to estimate your loaded weight, not the dry weight in the literature. A diesel 20' should provide the performance you mention with the correct props. The desing of these boats makes them not well suited for speeds much over 30 mph anyway. The new 200 Open with a diesel option literature states a 27 mph cruise with a range of 470 miles at that speed. that is with the 125hp Yanmar diesel and 90 gallons of fuel. That is over 6.5 mpg. That is incredible for a true inboard. Your pilot house and reduce hp will lower those targets for you, but you still have one hell of a package.
--------------------------------------------------------------------------------
Thanks, Lee
Date: 10:39 p.m. on 03-29-2001