Counter-rotating surfacing marine drive

A marine drive having two counter-rotating surface operating propellers comprising:

• a housing having upper and lower spaced horizontal bores and an intersecting vertical bore extending therebetween,
• said vertical bore having an upper threaded portion;
• an upper input shaft in said housing;
• a downwardly extending driveshaft in said vertical bore and driven by said input shaft;
• a pair of lower concentric counter-rotating propeller shafts in said lower horizontal bore and driven by said driveshaft;
• a pair of counter-rotating surface operating propellers each mounted to a respective one of said propeller shafts;
• an upper gear in said housing and operatively connected between said input shaft and said driveshaft;
• and
• an upper adaptor spool having a threaded portion mating with said upper threaded portion of said vertical bore in thread mounted relation and supporting said upper gear for rotation about said driveshaft,
• wherein:
• said adaptor spool has a lower outer section of a first outer diameter and threaded and mating with said upper threaded portion of said vertical bore;
• said adaptor spool has a center outer section above said lower outer section and of a central outer diameter larger than said lower outer diameter;
• said adaptor spool has an upper outer section above said lower outer section and of an upper outer diameter less than said central outer diameter and less than said lower outer diameter;
• said adaptor spool has a lower inner section of a lower inner diameter within said vertical bore;
• said adaptor spool has a lower inner section above said lower inner section and of an upper inner diameter less than said lower inner diameter;
• and comprising:
• an upper outer bearing between said upper gear and said upper outer section of said adaptor spool and supporting said upper gear for rotation about said adaptor spool;
• and
• an upper inner bearing between said driveshaft and said upper inner section of said adaptor spool and supporting said driveshaft for rotation in said adaptor spool.

A marine drive having two counter-rotating surface operating propellers comprising:

• a housing having upper and lower spaced horizontal bores and an intersecting vertical bore extending therebetween;
• an upper input shaft in said upper horizontal bore;
• a downwardly extending driveshaft in said vertical bore and driven by said input shaft;
• a pair of lower concentric counter-rotating propeller shafts in said lower horizontal bore and driven by said driveshaft;
• a pair of counter-rotating surface operating propellers each mounted to a respective one of said propeller shafts;
• said vertical bore having a first section of a first inner diameter;
• said vertical bore having a second section above said first section and of a second inner diameter larger than said first inner diameter;
• said first and second sections meeting at an upwardly facing annular shoulder;
• said vertical bore having a first thread above said second section and of an inner diameter at least as great as said second inner diameter;
• said vertical bore having a third section above said first thread and of a third inner diameter greater than said second inner diameter;
• and
• said vertical bore having a second thread above said third section and of an inner diameter at least as great as said third inner diameter.

A marine drive having two counter-rotating surface operating propellers comprising:

• a housing having upper and lower spaced horizontal bores and an intersecting vertical bore extending therebetween;
• an upper input shaft in said upper horizontal bore;
• a downwardly extending driveshaft in said vertical bore and driven by said input shaft;
• an upper gearing said housing and operatively connected between said input shaft and said driveshaft;
• a pair of lower concentric counter-rotating propeller shafts in said lower horizontal bore and driven by said driveshaft;
• a lower gear in said housing and operatively connected between said driveshaft and said propeller shafts;
• a pair of counter-rotating surface operating propellers each mounted to a respective one of said propeller shafts;
• a lower bearing at the bottom of said vertical bore and supporting said driveshaft for rotation;
• and
• an adaptor spool at the intersection of the top of said vertical bore and the bottom of said upper horizontal bore and supporting said driveshaft for rotation, wherein
• the vertical distance between said adaptor spool and said lower bearing is about equal to propeller radius.

A marine drive having two counter-rotating surface operating propellers comprising:

• a one-piece unitary integrally cast housing having upper and lower spaced horizontal bores and an intersecting vertical bore extending therebetween, said vertical bore having an upper threaded portion below said upper horizontal bore;
• an upper input shaft in said upper horizontal bore;
• a downwardly extending driveshaft in said vertical bore and driven by said input shaft;
• a pair of lower concentric counter-rotating propeller shafts in said lower horizontal bore and driven by said driveshaft;
• a pair of counter-rotating surface operating propellers each mounted to a respective one of said propeller shafts;
• an upper gear in said housing and operatively connected between said input shaft and said driveshaft;
• an adaptor spool at the intersection of the top of said vertical bore and the bottom of said upper horizontal bore, said adaptor spool having a threaded portion extending downwardly into said vertical bore below said upper horizontal bore and mating with said upper threaded portion of said vertical bore in thread mounted relation and supporting said upper gear for rotation about said driveshaft.